Archive for the ‘Messier objects’ Category

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A birthday observing run at the Webb Schools Hefner Observatory

June 16, 2014
Spiral galaxy M81

Spiral galaxy M81

My birthday was June 3. That evening, fellow PVAA member Steve Sittig invited me up to the Hefner Observatory at the Webb Schools in north Claremont. Steve teaches science at the Webb Schools, and he has a particular interest in physics and astronomy. The dome at the Hefner Observatory houses an orange-tube C14 Schmidt-Cassegrain. Observing with us were two other Webb faculty members, Andy Farke (paleontologist, blogger) and science teacher Andrew Hamilton. Andrew Hamilton had brought along his DLSR, a Sony Alpha33—this would turn out to be important.

Starburst galaxy M82

Starburst galaxy M82

We got started a little after 9:00 PM with a look at Jupiter, which was low in the west. We noticed right away that the seeing was pretty darned good. We went on to the waxing crescent moon and then Mars and Saturn. After that we turned to the deep sky. M81 and M82 looked great, so we hooked up Andrew’s DSLR and attempted some photography. We didn’t have a remote shutter or computer control, so we were using only the camera’s native controls, and assessing the results on the LCD screen.

Planetary nebula M57, the Ring Nebula

Planetary nebula M57, the Ring Nebula

After the galaxies, we went on to the Ring Nebula, M57, and then the Great Globular Cluster in Hercules, M13. Even with the 30-second exposures that the camera was natively limited to, we were getting very respectable images. I am including a few here.

M13, the Great Globular Cluster in Hercules

M13, the Great Globular Cluster in Hercules

Our results were pretty primitive compared to what people can do with dedicated astro cameras and post-processing, but we still had a grand time, and the process was sufficiently rewarding that we stayed out until almost two in the morning. All in all, a pretty darned good birthday present. Hopefully we’ll be able to reconvene and shoot some more this summer. I’ll keep you posted.

Many thanks to Andrew Hamilton for permission to post these photos.

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A hydrogen bomb detonated against your eyeball

November 28, 2013

…would deliver less energy to your retina than a supernova observed from a distance of one astronomical unit (AU; the distance from the Earth to the sun). How much less? From this XKCD What If:

Which of the following would be brighter, in terms of the amount of energy delivered to your retina:

A supernova, seen from as far away as the Sun is from the Earth, or

The detonation of a hydrogen bomb pressed against your eyeball?

Applying the physicist rule of thumb suggests that the supernova is brighter. And indeed, it is … by nine orders of magnitude.

That rocked me back on my heels. And it got me thinking: how far away would one have to be for a supernova to be only as bright as an h-bomb pressed against one’s eyeball?

H-Bomb

Radiated energy is subject to the inverse-square law, by which intensity of radiation is inversely proportional to the square of the distance. So the answer  to my question is the square root of billion in AU, which is 31,623 AU, which is almost precisely half a light year. (BTW, Google will translate AU to light years for you!)

So if you’re close enough to a supernova that the light takes six months to reach you, it will still be like being nuked at point-blank range.

How far away from a supernova do you need to be to be safe? According to this article, even at a distance of 3000 light years, a supernova could still wreck the ozone layer of an Earth-like world.

Even more suprisingly (to me, anyway), the 1006 and 1054 supernovae apparently left detectable chemical traces on Earth, despite being 7200 and 6500 light years away, respectively. From farther down in the same article:

Gamma rays from a supernova would induce a chemical reaction in the upper atmosphere converting molecular nitrogen into nitrogen oxides…. In 2009, elevated levels of nitrate ions were found in Antarctic ice, which coincided with the 1006 and 1054 supernovae.

Amazing. The 1054 supernova is near and dear to my heart. Its visible remnant, the Crab Nebula, is also catalogued as Messier 1. I have observed it dozens of times, most notably during my nearly-annual Messier Marathons. I had no idea that it had literally left its mark on Earth.

So, here’s something to be thankful for this Thanksgiving: there are no particularly good supernova candidates close enough to Earth to pose a serious threat. All of the contenders are not massive enough yet (if they’re white dwarfs) or too far away, or won’t blow for millennia, or some combination of the above. So you can tuck in with abandon. We could still be annihilated at any moment by death from space–just ask the folks in Chelyabinsk–but it probably won’t come in form of a supernova.

Hat tip to Mike.

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Observing Report: Night of the Refractors redux

November 20, 2013
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From left to right: my TravelScope 70, my C102, David’s C102. When I took this picture, we hadn’t put the finders on the big scopes yet, or gotten my stand-alone GalileoScope set up yet.

This one is a little late: David DeLano and I spent the night of Sunday, November 3, observing at the Salton Sea. This is the belated observing report.

We met up at the visitor center at the headquarters campground. We rendezvoused there a little after 3:00 in the afternoon because we had some things to do before sunset, which because of the time change was coming at 4:50. The visitor center gift shop has a little astronomy section and both of us picked up a copy of the Sky Atlas for Small Telescopes and Binoculars, by Billie and David Chandler–more on that atlas another time. David also picked up a nice plasticized version of the Chandler planisphere.

Chandler Sky Atlas

After that we drove down to my favorite spot at the Sea, which is the south end of the Mecca Beach campground. A couple at another site were loading up as we were pulling in, and the left a few minutes later. After that, we were the only humans at the campsite all night long, except for someone in the late evening who pulled in, turned around, and left, all without stopping.

Our first activity was dinner at a picnic table in the shade. We split the gear and groceries like so: David supplied firewood and snacks, and I brought dinner (Subway sandwiches) and cooked breakfast (pancakes).

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Even as we were eating, the second activity commenced: the exchange of hostages. As far as I can tell, David is a hot rod mechanic who happens to work on small refractors instead of cars; if that strikes you as hyperbole, just read on. Anyway, he’s way more adept at getting refractors to sing than I am, so I had brought him an unfinished Carton 60mm f/15 refractor and a couple of small objectives that I had rescued from otherwise unsalvageable garage sale scopes. To transfer into my care, David had brought a nice Celestron 2-inch star diagonal for my C102, and–most importantly–a GalileoScope that he had built and modded for me.

Galileo is Rocking Out in His Grave

The GalileoScope was created for the International Year of Astronomy in 2009, when it originally sold for $15. That was mostly down to economy of scale; now that sales have cooled, the price is up to about $50. It’s still a lot of telescope for that price. David’s GalileoScope mods have been featured here before.

The stock GalileoScope is a straight-through instrument with an f/10 objective and a push-pull focuser, which you aim by looking along some gunsight-style ridges on top of the OTA. My GS has had its tube chopped to accommodate a Stellarvue 90-degree diagonal with a helical focuser (the #D1026AF unit here, if you want one for yourself), and has a Daisy red-dot finder perched on the forward gunsight.

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Above, my nicely tricked-out GalileoScope. Bottom, David’s insanely modded version–possibly the most attention anyone has ever lavished on a cheap build-it-yourself 50mm refractor.

Lest you get too jealous of my pimped-out GalileoScope, let me describe David’s own GS. He got the aftermarket f/11 objective kit, which lengthens the light path enough to allow the use of a diagonal without chopping the tube. At the back end of the scope, there’s a 2″ Crayford focuser (yes, you read that right) with a 1.25″ adapter. His diagonal also has a helical focuser for fine-tuning; in fact, in use I forgot about the Crayford and used the helical focuser exclusively. At the front end, there’s some kind of fancy RDF, sold by Cabella’s for use by hunters, with the largest eye-lens I’ve ever seen apart from the “boxy” astro-only unit-power finders, the Telrad and the Rigel Quikfinder. A set of nice rings with Delrin-tipped screws completes the instrument, and allows David to mount it coaxially with his larger scopes as possibly the most awesome luxo-finder-slash-second-instrument that I’ve ever encountered (on a small scope; the 9.5-inch refractor mounted on the 12-inch Zeiss in the Griffith Observatory probably takes the cake for larger instruments).

David’s GS really must be seen to be believed. Once on the Dinosaur Mailing List, Mickey Mortimer wrote, “Looks like it’s time to over-technicalize this previously tame post.” I can’t think of David’s GS without those words going through my mind. I wouldn’t be surprised if it is the most extensive hack anyone has done on a GS. It is definitely the most badass.

I should mention that getting both of the GalileoScopes to work as well as they do involved a lot more than just throwing some nice parts on. It required a lot of work and thought and experimentation. Happily, David documented the process and will have a guest post about his adventures in GS-hacking in the not-too-distant future. So stay tuned for that.

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David’s GS mounted on his C102 as the luxury finder to end all luxury finders.

After dinner and the exchange of hostages, it was time to set up scopes. I was rolling with the C102/SV50 combo again. I also set up the TravelScope 70 just to have something different to plink around with. David set up his second tripod for my GS, and put his mod-tastic GS on his own C102, using a third tube ring to support the GS stalk and rings. This makes for an imposing setup. I studied it as intently as an American astronaut getting his first look under the hood of a Soyuz capsule. We used some antennas on a distant mountaintop to get everything aligned, and then almost immediately we were off and running.

Skyward!

Our first target, at 5:30, was Venus. There wasn’t much to see–basically a very bright half-circle–but checking in just feels like the right thing to do.

Next we turned to the Double Cluster and Stock 2 and spent a few enjoyable minutes tracing out the loops and chains of stars in our various instruments. Like last time, I could see the red stars in NGC 884, and if anything they were easier this time since I knew what to look for.

After that we turned south and did a big tour of the Sagittarius/Scutum area, eventually going north into Aquila and then west through Serpens to Ophiuchus. But I’m getting ahead of myself.

We started with the teapot asterism in Sagittarius, and let that guide us to M8, the Lagoon Nebula. Then we hopped up just a bit to M20 (the Trifid Nebula) and the open cluster M21. After that we took a break to hit M13 in Hercules before it sank down into the light dome over Palm Springs. We returned to Sagittarius with globs on the brain and took in M22, which I thought was a serious contender in the field of majestic globs. Then it was up to the M24 star cloud, where we got lost for a few minutes at the sight of literally thousands of stars in our eyes. Somewhere in Seeing in the Dark–and irritatingly I cannot find the passage right now–Timothy Ferris describes a swath of the sky, possibly M24, as a “wonderland of far-flung suns”. Whether he intended it for M24 or not, it’s an apt description.

At the risk of letting my current bout of refractoritis get the best of me, I must say, the view of M24 through the C102 was just breathtaking. Now, I have visited M24 before, many times. It is one of my favorite places in the sky. But I had not taken a good look at it through a decent-sized refractor under dark skies. The contrast was superb: against a jet-black background, the stars were so finely graded by brightness that I noticed rivers and shoals among them that I had never been aware of before, including a current of brighter stars running north-south and paralleling the Milky Way. Truly, this is the backbone of night.

But even in a palace, one can want for variety (or so I’ve heard), so we ventured onward. Past the open cluster M18 we came to the Swan Nebula, M17, very bright and clear and looking just like its namesake. Then farther up we found M16, the Eagle Nebula, its tendrils of glowing gas wrapped around a dense cluster of newborn stars. Then back to M24 to pick up the open clusters M25 and M23, which attend the majestic star cloud like obsequious courtiers. M25 is one of my favorites; it sits at the center of a curving arc of stars that David describes as a spiral, but that to me has always looked like a fishhook, with M25 as the bait.

After working through all of those objects with the scopes, we stopped for a binocular tour. I had along my Nikon Action 10x50s and David was rolling with his Nikon action 10x40s. I found that if I held David’s green laser pointer between two fingers of my right hand and the binoculars, I could aim the laser beam at the center of my field of view. We shared many sights over the course of the evening using this trick. For starters, we revisited all of the Sagittarius clusters and nebulae mentioned above, and picked up the little glob M28 as well.

DeLano 1 chart - wide

The asterism “DeLano 1” next to Mu Aquilae. It is much more obvious than this Stellarium view shows, and looks more like a bright open cluster.

Then we turned north to Scutum and Aquila. Our first stop was M11, the Wild Duck cluster. Then I took a break for bathroom and snacks, and David went crazy finding new things. When I got back to the scope, I had some catching up to do: the open clusters IC 4756 in Serpens, and NGC 6633 and IC  4665 in Ophiuchus. David had also discovered something pretty that was not listed on any of our charts: a small group of bright stars just north of Mu Aquilae. So far I have not found this listed anywhere as a named object; for the heck of it we called it DeLano 1.

DeLano 1 chart 2 - narrow

A closer view of DeLano 1.

Zoom Zoom Zoom

I see that I have not mentioned what I was using for eyepieces. Thanks to the 2″ diagonal I could use my 32mm Astro-Tech Titan, which gives a wider true field than any other eyepiece I own. In the C102 it gives a magnification of 31x and a 2.2-degree true field of view, which was great for framing almost everything we looked at (the Pleiades fit with a little room to spare, even). My only other 2″ or dual-barrel EPs are the 21mm and 13mm Orion Stratus EPs, which I used infrequently Sunday night. When I wanted more power, I put in the 1.25″ adapter and my new toy, the Celestron 8-24mm zoom eyepiece.

My only previous experience with a zoom EP was a Scopetronix 7-21mm, which was pretty stinky. Zoom EPs always have wider apparent fields of view at high magnification and narrower AFOV at low magnification. That is pretty much the opposite of ideal, but physics is physics, and the comparatively narrow apparent field is tolerable as long as it doesn’t get too narrow–below about 40 degrees you feel like you’re looking through a soda straw. Unfortunately, with the Scopetronix zoom, the AFOV started at 40 degrees (at high mag) and ended up somewhere below 30, at which point the image is so small you might as well be looking through the other end of the telescope.

Happily the Celestron 8-24mm zoom has a more generous AFOV. The stated range is 40-60 degrees, and that seems about right to me. What’s not so great? It’s not parfocal across its magnification range (I don’t know how many zoom eyepieces are), so you have to refocus as you change magnification. Also, it’s a little soft at high power. Not egregiously so, but my 8.8mm ES82 is not going to be losing any sleep. On the plus side, it’s decent, convenient, and at a current street price under $55, dirt cheap.

Incidentally, this is the danger of getting a couple of high-end eyepieces: they are so sharp and so clear that when you go back to merely average EPs, the differences are immediately noticeable. It makes you spoiled.

Lyra, Cygnus, Vulpecula, and Sagitta

After I got caught up in Ophiuchus, we turned north, first to Polaris and the “Engagement Ring” asterism, and then to the Lyra/Cygnus/Sagitta area.

Naturally our first stop was Epsilon Lyrae,  the “double double” star, which was cleanly split at 125x with 8-24mm zoom. So if you’re curious about that eyepiece, there’s a point in its favor.

After that we followed my usual J-shaped path through this  region: from the Ring Nebula, M57, on past the fair-to-middlin’ glob M56 to the brilliant, contrastingly-colored double star Albireo. Like a lot of double star observers, I like doubles when they’re not too widely split, and at 31x the 32mm Titan and C102 gave perhaps the best view of Albireo I’ve ever had in a scope. After Albireo, go straight south to find Collinder 399, better known as Brocchi’s Coathanger. Southwest of the Coathanger one comes to the pair of closely-spaced, equally-bright stars that mark the feather end of the constellation Sagitta, the arrow. Halfway along the arrow a zig-zag pattern of stars leads to the faint glob M71. Then proceed along the arrow to the third bright star up from the feathers and hang a right to find M27, the Dumbbell Nebula.

The Dumbbell does a neat trick as either one’s scope or one’s sky conditions improve. From a small scope, or a big one under city lights, it looks like a bow tie. As things get better, the ends of the bow tie sprout extensions to either side, so the nebula starts to look more like an apple core. Finally the area to either side of the apple core starts to fill with nebulosity, so the nebula ends up looking like a football with a bright band–the former bow tie/apple core wrapped around its “waist”.

10-04-2008_DumbellThe football form of the nebula is obvious in most astrophotos of M27. Here’s a nice example by Rogelio Bernal Andreo (DeepSkyColors.com) that shows the different aspects in different colors: white bow tie center, red apple core extensions, blue football wings. I have seen the football before in the XT10, but I had never seen it in a small scope before Sunday night. And, to be clear, the C102 did not show the entire football. But it did definitely show the wisps of nebulosity extending out on either side of the apple core. It’s probably  best to say that M27 was halfway between  the apple core and football forms. It was missing the crisp cut-off at the edge of the football, which the XT10 will show under sufficiently dark skies. But it was still way more than I expected. I am still learning what a 4-inch scope with high contrast can do under dark skies; the answer is, “an awful lot”.

The striking appearance of M27 can in part be chalked up to excellent transparency in the early evening. Another example is that both of us could clearly make out the North American Nebula, NGC 7000, in the binoculars. My best-ever views of the nebula have been with 15×70 bins out at Owl Canyon. I have caught glimpses of it in the 50mm glasses before, but never as good as it was Sunday night. David was getting it clearly in his 40mm bins, which is pretty amazing.

We did another binocular tour in this area, hitting all of the objects listed above as well as M29, M39, the heart-shaped asterism around the bright star Sadr in the heart of Cygnus, and the wide blue/orange binocular double Omicron Cygni. This was about 8:30 PM, four hours into our 9-hour run.

This is pretty much how we proceeded for the rest of the night: pick an area, figure out some of the best and brightest objects therein, and hop our way through them. David was working off the Evening Sky Map and suggesting objects from its lists, and I was working from the PSA and rediscovering some goodies I hadn’t seen in a while. Rather than give an exhaustive list of everything else we saw, I’ll just list some highlights:

NGC 253 and NGC 288 – NGC 253 is the Silver Coin Galaxy. It’s up there with Andromeda (M31), the Whirlpool (M51), the Sombrero (M104), and Bode’s Nebulae (M81 & M82) as one of the best galaxies for northern hemisphere observers. My first view of it was in binoculars from Big Bear Lake, and under those dark mountain skies it looked as good in the 15×70 bins as a lot of galaxies look through a telescope. Mottled details is visible in even small scopes under sufficiently dark skies. While you’re in the area, might as well drop down about one eyepiece field and pick up the globular cluster NGC 288.

NGC 7789 – Here’s one I’d seen before but forgotten about. This is a nice open cluster off the tip of Cassiopeia, sandwiched between two small groups of bright stars. There are a lot of open clusters in Cassiopeia–we did a third binocular tour that encompassed NGC 457, NGC 436, M103, NGC 663, NGC 659, NGC 654, and Cr 463–but NGC 7789 might just be the best, not only for its inherent charm but for the rich surroundings in which it is set.

M37, M36, M38 – This is the famous trio of open clusters in Auriga, which are among the most popular and  most visited objects in the winter sky. The one that impressed us the most Sunday night was M37, the lowest (east-most) one. It is a dense swarm of tiny stars, which David described as “crystals”, and which to me looked like the proverbial scattering of diamonds on black velvet.

M46, M47, M93 – These open clusters in Puppis are also popular winter objects, especially the close pair of M46 and M47. I suspected the planetary nebula NGC 2438 in M46, which I first spotted at the All-Arizona Star Party back in 2010. Since then, I always look for it, and when I do spot it, I wonder how I was able to go  for so long without seeing it.

M76 – This is the Little Dumbbell Nebula in Perseus, and one of just a handful of planetary nebulae in the Messier catalogue (the others are M27, M57, and M97). As its name implies,  the Little Dumbbell is the smallest and probably least impressive of the Messier planetaries, but I’ve always had a fondness for it. Although small, it has a high surface brightness so it’s not hard to spot if you know where to look, and it is not without its charms.

Planetary nebulae illustrate why the Messier catalogue is a two-edged sword. On one hand, the Messier catalogue does include some best-of-class objects in almost every category of DSO; on the other hand, there are numerous objects in other catalogues that outshine (sometimes literally) the less impressive Messiers. For galaxies, you have things like the Silver Coin and NGC 4565 in Coma Berenices; for open clusters, look no farther than the Double Cluster in Perseus and NGC 663 and NGC 7789 in Cassiopeia; for diffuse nebulae, see the Flame Nebula (NGC 2024), the Rosette (NGC 2237), and the Christmas Tree or Cone Nebula (NGC 2264).

But planetary nebulae get especially short shrift; a quick-and-dirty list of impressive non-Messier planetaries in northern skies includes the Cat’s Eye (NGC 6543), the Eskimo (NGC 2392), the Saturn (NGC 7009), the Ghost of Jupiter (NGC 3242), and the Blinking Planetary (NGC  6826). This is not because Messier had anything against planetaries but because his catalogue was discovered rather than assembled post-hoc, and discovery is always a haphazard process. Still, we are not discovering these things for the first time, and with their often high surface brightness and charming array of forms, planetary nebulae are great targets for beginning and city-bound observers.

By 2:00 AM we were winding down, and so were the skies. A cloud mass that had been hovering over Palm Springs started to send forth offspring, and the haze near the horizon was getting worse. A bright star in Leo that I just couldn’t place turned out to be Mars. We had one last look at the Double Cluster and called it a night.

It was one of the most fruitful observing runs I’ve ever had. By my count, we looked at:

  • 49 Messiers
  • 20 NGC, IC, Collinder, etc., objects
  • 4 double stars (counting Epsilon Lyrae only once)
  • 4 asterisms (DeLano 1, the Engagement Ring around Polaris, the Heart around Sadr, and Kemble’s Cascade)
  • 3 planets (Venus, Jupiter, Mars)

So about 80 things in the sky, not counting the numerous shooting stars, which we noted every few minutes all night long. That is by far the most things I’ve seen in one evening when I wasn’t doing a Messier Marathon. But we weren’t rushing or trying to get through a ton of objects, we were just basically out for a spin, and if you cruise around the sky for 9 hours, you are going to end up seeing a lot.

Lessons

I came away from the evening with a couple of firm directions for future observing.

First, I don’t think I logged anything that I hadn’t seen before (DeLano 1 excepted!), but I saw a lot of stuff that I had forgotten about, like NGC 7789. Most of these were things that I had visited in the course of doing one or another Astronomical League observing program. That’s great because those programs have helped me to learn the sky, and they’ve introduced me to a lot of wonderful objects that I hadn’t seen before. But now that I know the sky, I need to go back and re-observe those things and spend a little more time with them. This is especially true of the many beautiful clusters on the Deep Sky Binocular observing list–I am ashamed to say that there are many of those that I still have not visited with a telescope. So even my terra cognita holds some wonderful things waiting to be rediscovered.

Second, I need to go south (in the sky)! Here’s some relevant math: the Salton Sea campgrounds are at about 33 degrees north latitude. That means that Polaris is 33 degrees above the northern horizon, the celestial equator is 57 degrees above the southern horizon, and with no intervening landforms or atmosphere I should be able to see down to -57 degrees declination when I look south. Now, in practice the near-horizon haze makes the last few degrees pretty worthless. But I have seen the globular cluster Omega Centauri with my naked eyes from the Salton Sea. At -47 degrees declination, it never gets more than 10 degrees from the horizon. If it’s naked-eye visible that low under good conditions, then binoculars and telescopes will reveal much more at the same declination, and maybe even a little lower.

In practice, I have explored almost none of that southern expanse. I am used to thinking of the Silver Coin galaxy as a far southern object, but at -25 degrees it culminates a full 32 degrees above the horizon–more than a third of the way to the zenith! Except for sighting Omega Centauri a couple of times, I have not deliberately gone south of about -30 degrees declination (and I’ve only gotten there in the area around the “tail end” of Canis Major), which leaves a LOT of unexplored sky out there. I was fortunate to get to see most of the best of the southern hemisphere sky when I was in Uruguay in 2010 and it was amazing. Much of what I saw there is visible from here, I just haven’t looked. I need to fix that.

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Suburban Messier project–gear? rules? company?

July 20, 2012

Part 1: Inspiration

I am contemplating a new observing project. It started back in May, when Doug wrote a long comment that ended with:

You know what we need? Really, really need. One of these guys: O’Meara, Sue, Tony Flanders, etc. to write a book complete with sketches, using a Real People telescope in a typical residential suburban setting. A Celestron or Meade or Orion sub-$500 scope from a backyard or driveway in Torrance or Sacramento or Cleveland and do all the Messiers . . . or whatever. Then you’d have something you really could use with goals you had a realistic chance of achieving.

Come to my house, or one like it and do all your observing here. For a year. Sketch what you see through the eyepiece of a real world scope in a real world setting. Then I can say “Ah, so THAT is the pattern I am looking for.” And will recognize when I see it….

Hey, Matt, YOU have real world scopes. And a backyard. So, maybe you?

And I wrote:

Your question inspires me. I had already been thinking about doing a Messier survey with a small scope, just to see what could be achieved. I may fire up that observing program one of these days. If I do, I’ll try my hand at sketching, too. It probably won’t be soon. Our skies here suck in the summer, with lots of haze and smog and not much wind to blow it out. And it’s too hot to go to the desert. But I might do some runs up Mount Baldy, which is acceptably dark but not stupid-dark like the Mojave.

So, at first I was just thinking of doing a small-scope Messier tour, from wherever, including Mount Baldy and the Salton Sea. But I think that would be of limited usefulness. The orange/yellow zone skies on Mount Baldy are something that a lot of folks would have to drive to get to. The blue/grey zone skies at the Salton Sea are way too dark to be useful for what Doug was describing. Not at all like what you’d get in “Torrance or Sacramento or Cleveland”. If it’s going to be a suburban Messier survey, it needs to be from in town–specifically, from my front yard and driveway (my back yard has a verdant canopy of greenery which is beautiful but not good for stargazing).

The other part of this is that I have never sketched deep sky objects. I have often sketched planets, very approximately, to show how many cloud belts and moons I could see, and I have been sketching my way through the AL Double Star Club observations, but c’mon, that requires drawing 2-4 tiny circles. I haven’t sketched DSOs, and I think it’s a skill I should cultivate.

My desire to learn to sketch DSOs has been intensified by observing with Terry Nakazono, who sketches, and by seeing the really nice sketches done by fellow PVAA member Justin Balderrama (who blogs here). Justin is in his teens, but you’d never know it to flip through his observing logbook. And these guys don’t make a big deal out of their sketching–it’s just part of their observing technique. I dig that. I’d like to do that.

Part 2: The Rules

Okay, so I’m going to observe and sketch all the Messier objects from my yard. Using what?

For a while I toyed with the idea of getting one of Orion’s $100 tabletop scopes, the SkyScanner 100 or GoScope 80, just for this project. But lately I’ve been cutting back on scopes–I just sold Shorty Long and Stubby Fats–and I’m loathe to turn around and start piling them up again. The scope is going to have to be one I already own.

My current lineup includes:

  • XT10 (10″ or 254mm)
  • Apex 127 (5″ or 127mm)
  • Skywatcher Mak (3.5″ or 90mm)
  • Travel Scope 70 (2.75″ or 70mm)
  • SV50 (2″ or 50mm)

Since this is a small-scope project, the XT10 is out. I’m throwing out the Apex 127, too. Using Doug’s original “sub-$500″ criterion you could buy the OTA, but you couldn’t mount it securely, not unless someone was having a ridiculous sale on mounts. And, fer cryin’ out loud, Uncle Rod uses a 5” Mak as his back-up deep-sky scope (which is one of the reasons I got one for myself), so I think it’s big enough to also be disqualified for a small-scope challenge.

On the other hand, the SV-50 is too small. Reeling in all the Messiers with it would be an interesting challenge from a dark site, but from town it would be straight-up murder. Plus, I doubt too many amateurs these days are starting out with a 50mm scope. Anyone who can afford a 50mm scope can probably afford 10×50 binoculars (currently $25 at Amazon for a decent pair), and those will frankly be a lot easier to use.

That leaves the 90mm Mak and the 70mm refractor. And here I’m just going to make a command decision and go for the 90mm Mak, for a lot of reasons. The biggest is comfort. If I’m really logging, sketching, and taking notes, I reckon I’ll need about a half hour per object. Multiplied by 110 objects means 55 hours of observing time, minimum, spread out over the next year or two. If I’m going to spend that much time with any one scope, it has to be comfortable for both eye and body. The optics on the Travel Scope 70–on my example, anyway–are swell up to about 20x, acceptable up to about 40x, and frankly pretty gross after that. In contrast, I’ve had the little Mak up over 200x regularly with no image breakdown, and it’s got a nice flat field that is essentially free of aberrations.

The “body” side of the comfort equation is why I’m not using my son’s Astroscan. For him it’s fine sitting on a folding chair or even on the ground. For me it needs a table, which is never as stable as a tripod, and more of a pain to move around late at night in the dark. And like the TS70 it is wonderful for bright, wide, low-power scanning, but runs out of magnification pretty fast.

My one reservation about using the 90mm Mak is the long focal ratio–1250mm, or two inches longer than the XT10 even–which means high minimum powers and a narrow field of view. The max true field in this scope is only a little over 1 degree (compared to a max true field of about 4 degrees for the TS70), which is not enough to fit in the largest Messier objects. I’m not worried about the Pleiades–I’ll just scan around to see them all–or M31, where I’m unlikely to see more than just the core from town. It’s M33, the Triangulum galaxy, a large not-quite-face-on spiral galaxy, that makes me sweat. It’s going to be hard enough to see from town in the first place, let alone in a scope that won’t fit the whole thing into the field of view at once. But no scope is perfect for every job, and I want this to have some element of challenge, so I’ll stick with the little Mak.

I’ve also decided to eschew fancy eyepieces for this project, and just use ordinary Plossls, probably my 32mm (39x) and the three that came with the scope: 25mm (50x), 12.5mm (100x), and 6mm (200x). I strongly suspect that the 25mm is all I’ll need for most objects. A lot of DSO hunters recommend a 1-degree true field for finding objects and a 2mm exit pupil for observing them. In the 90mm Mak, the 25mm Plossl gives almost exactly those values:

True field of view (TFOV) = Apparent field of view (AFOV)/magnification; in this case 52 degrees/50x = 1.04 degrees.

Exit pupil = aperture/magnification; in this case 90mm/50x = 1.8mm exit pupil.

As with the fancy eyepieces, using the nice Astro-Tech dielectric diagonal feels like cheating.  I sold the 90-degree prism diagonal that came with the scope–I couldn’t get it out of the house fast enough. That leaves either a 45-degree erect-image prism diagonal that I just discovered I had the other day (which is the only reason I haven’t sold it yet), or an $8 mirror diagonal I bought off Cloudy Nights. Either is probably a good match for what would come with a beginner scope, but I’m going to use the cheap mirror diag. More Maks are sold with prism diagonals, but whatever, I can’t put myself through that many hours of looking through a low-end prism, and I don’t think substituting a piece of gear that costs less than ten bucks will corrupt the replicated beginner experience.

Now, the big question: what finder should I use? At first I was thinking I would just roll with the 9×50 RACI. It’s my favorite and most-used finder, and observing with it would be a cinch. But I am reluctant to do that, for two reasons. First, I know how to find stuff with a 9×50 RACI. It’s not going to push me or teach me anything. Also, I think it sort of violates the spirit of observing with the stuff that Joe Newbie would have available. A 9×50 RACI is a big upgrade, close to half of what I paid for the 90mm Mak in the first place. That leaves other three finders that I have lying around that I could potentially use:

  • The 20mm erect-image finder that came with the scope. Gag me with a stick. I know that a lot of 90mm Maks ship with these things, but they shouldn’t. This finder is good for two things: gathering way too little light, and making people hit their face on the scope when they try to get their eye behind it (you can see a close call here). For the love of Pete, if your scope came with one of these and you can’t afford anything better, get over to Telescope Warehouse and get a 6×30 finder with a bracket for $18-20 or a dot finder for $14 (also, if you just flat need a scope, they have 70mm achromatic refractors for $22 and 90mm achromats for under $40, although you’ll have to rig a mount).
  • The 6×26 straight-through erect-image finder that came with the Apex 127. I forgot this existed until I found it in an unlabelled box when I was cleaning up the front room.
  • The red dot finder that came with one of my other scopes at some point, which I never got around to selling.

There are actually valid arguments for both the 6×26 and the RDF. Most entry-level scopes these days ship with RDFs, including all of the Orion tabletop scopes, so for replicating the beginner experience it is probably the most legit. With a max true field of 1 degree in the scope, though, it will make for some punishing star-hops. The argument for the 6×26 comes from Jay Reynolds Freeman’s essay “Finding deep sky objects rapidly”:

I use magnifying finders instead of unit-magnification ones because I need to see more than just naked-eye stars to point the telescope accurately, and the extra light gathered by magnifying finders provides them. I use straight-through ones because I can keep both eyes open and use the finder cross-hair as a reflex sight, fused by the brain with the view through the other eye.

I don’t know that trick, but I’d like to.

Both the RDF and the 6×26 will be irritating in that they’ll force me to get my head behind the scope, but I reckon it’s time I learned more than one way of finding so I’m willing to make the sacrifice. Anyway, I’m still undecided on which one to use, but maybe you can help me out with that.

Part 3: Audience Participation

Now, gentle reader, I have three questions for you. Before we get to them, let’s review the plan:

I will (1) observe–or attempt to observe–and (2) sketch (3) all of the Messier objects (4) from my front yard/driveway (5) using my 90mm Mak and (6) inexpensive eyepieces. I don’t have a fixed schedule in mind, but doing the whole list in a year does not seem prohibitively difficult or time-intensive; that’s only 2 objects per week, on average.

The one hang-up there is that the dimmest objects will probably have to be observed when they culminate (get as high in the sky as they’re going to from  your latitude), possibly after midnight when a lot of folks shut off their lights and the LP slacks off a bit, which dictates a particular season. For the big mess of galaxies in Virgo-Coma, that means springtime, when the weather is iffy. I have gotten several of the Virgo-Coma galaxies from my driveway with 15×70 binoculars, but I wasn’t sketching or taking extensive notes, which will eat up observing time. In some cases it might not be a matter of going on dawn patrol to catch ones I missed, because in a small scope under LP they might only be visible near the zenith, late at night, during a narrow seasonal window. I’m going to try to get it done in a year, but if it slops over into a second year I won’t be devastated.

Now, if you’ve managed to hang with me this far, I have questions for you:

  1. Following the discussion in the previous section, which diagonal and–especially–which finder do you think I should use? Do you care? Is your interest more in seeing the beginner experience replicated from top to bottom, or just in the descriptions of the objects through a modest scope under light-polluted skies, in which case the mode of finding doesn’t really matter?
  2. Can you think of any other rules or conditions that would make the survey more informative/relevant/legit/challenging?
  3. Would you like to join me?

I’m dead serious on that last point. If you’ve never seen all the Messiers before, feel free to use whatever scope you like, from whatever observing site you like. Or use your big scope from home, or your small one from a dark site, or whatever–set whatever conditions you like for your Messier project. Sketch or don’t sketch, although it would be cool if you did, because then we could compare notes.

I’m planning to set up a sidebar page for this anyway, and scan and post my sketches and observing notes. I’d be happy to host yours, too, if you send them to me. I get 3 gigs of space on this blog, and so far in all of my time here I’ve only used 1/12 of it, so I’m not worried about running out of space by hosting too many images or PDFs or whatever.

I’d like to set an arbitrary start date of August 1 for my own survey, but if you happen to stumble across this post a few months from now and want to join in then, feel free.

Any takers? If so, let me know in the comments.

Clear skies!

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Observing report: All-nighter on Mount Baldy

July 15, 2012

Whew! Last night rocked. Terry Nakazono was out from LA, and we had been planning for about two weeks to spend the night observing up on Mount Baldy. We had made a shorter, half-night run up the mountain back in June, Terry to chase faint galaxies with his SkyScanner and me to log a few Herschel 400 objects with the XT10. Last night was basically the same plan, but on steroids–the moon was rising later, and neither of us had anywhere to be today. My wife and son were both out of town, she on work and he on a sleepover, so I was released on my own recognizance.

We got up there about 8:45 and met fellow PVAA member Craig Matthews setting up his 8″ Dob. Former PVAA president Ron Hoekwater joined us a little later on.

Terry was rolling with his SkyScanner again, and aiming for galaxies in Ursa Major and Bootes. I decided to leave the XT10 at home and take the Apex 127 Mak instead. I’ve had that scope for about a year, but before last night I had not really tried it out under dark skies. It did go to the Salton Sea in February, but we were mostly clouded out that night. Five inches is a lot of aperture under dark skies, and I was anxious to see what the Mak could do. Mount Baldy is not stupid-dark like Afton Canyon or western Arizona, but it’s not bad at all. The Milky Way was prominent and showed a fair amount of detail, especially after midnight when a strong marine layer at lower altitudes effectively halved the light pollution to the south (Inland Empire) and southwest (Los Angeles). On light pollution maps Baldy shows as being in the Orange zone, Bortle Class 5, but between the altitude and the marine layer it is sometimes effectively Green (Bortle 4). Last night was such a night.

I also took along the Celestron Travel Scope 70, which I had otherwise only used for quick peeks from my driveway. I’ve been meaning to blog about that scope. Right now you can get the scope, finder, two eyepieces, a tripod, and a backpack carrying case from Amazon for about $70 shipped. The finder is a travesty–an all-plastic “5×20” unit that is in fact stopped down to 10mm right behind the objective. I stripped the so-called optics out of mine and use it as a naked-eye sight tube, in which role it performs admirably, and a heck of a lot better than it ever did as a magnifying finder. The tripod is a joke, the sort of thing that gives other flimsy tripods a bad name. It struggles to hold a point-and-shoot digital camera steady, let alone a telescope, so I donated it to a museum. But the eyepieces are serviceable, the carry bag is fine, and the telescope itself is okay–more on this in the next post–so for $70 it is a screaming deal. As with the Apex 127, I was anxious to see what it could do under dark skies.

It was not yet fully dark when we arrived so I spent some time jawing with Craig. It was cloudless and clear where we were, but we could tell it was raining in the Mojave Desert, because the northeastern sky flickered with distant lightning. And we knew it was far off because we never heard even a hint of thunder. The lightning was not reflecting off clouds but off of the sky itself. It was as if the sky was on the fritz, like a bad florescent bulb. It was a profoundly weird and unearthly effect.

I started my observing run by putting the Apex 127 on Saturn. In addition to observing with “new” scopes, I was also rolling with genuinely new eyepieces. Explore Scientific has been having a CUH-RAY-ZEE sale on their well-reviewed 68, 82, and 100-degree eyepieces, so I sold some unused gear and bought a few: the 24mm ES68, which delivers the widest possible true field in a 1.25″ eyepiece, and the 14mm and 8.8mm ES82s. The Apex 127 is my longest focal length scope at 1540mm, so those eyepieces yielded 64x (24mm), 110x (14mm), and 175x (8.8mm). I also have a 6mm Orion Expanse that gives 257x–that is my default high-mag eyepiece in any scope. The ES eyepieces had just arrived in the mail last week so last night was my first time to try  them out.

Anyway, the seeing was limiting, with the view shaky at 175x and downright ugly at 257x, but Saturn was crisp and jewel-like at 110x and I could see four moons even at 64x. I haven’t checked the charts to see for sure which ones they were, but Titan certainly, and Dione, Rhea, and Tethys probably. I have seen up to five moons of Saturn at once before, but that requires steadier skies than we had last night.

After Saturn I hit a few favorite Messiers, including the globs M13, M5, and M4, all of which were impressively resolved for a 5″ scope. My favorite view of the evening through the Apex 127 was of the galaxies M81/M82 in the same field at 64x, with tantalizing hints of detail visible in both.

Then I got to work, finding and logging Herschel 400 objects. I was chasing mostly open clusters in Cygnus and Cassiopeia. I logged NGCs 6866, 7062, 7086, 7128, 7008 (a planetary nebula) and 7790. I also tried for open clusters NGC 7044 in Cygnus and 136 in Cassiopeia, but could not locate anything I felt comfortable calling a definitive open cluster at the charted locations amid the rich Milky Way starfields. This was also an issue with several of the Cygnus clusters I did log—at high magnification they tended to disappear into the surrounding star chains and asterisms.

Getting skunked is no fun, and by that time I’d been working on H400s for about two hours. For a change of pace, I switched over to the Travel Scope 70 and started plinking at Messiers. With a 32mm Plossl eyepiece I got 12.5x magnification and a stunning 4-degree true field–more like a finder on steroids than a telescope. I started with the Double Cluster as soon as I saw it was over the horizon, then hit M31, but didn’t immediately see its satellite galaxies. Then it was on to the “steam” rising from the teapot of Sagittarius: M8, M20, M22, M24, M25, M23, M18, M17, M16—these last three all nicely framed in the same field—M26, and M11 up in Scutum. Then back to the “bottom” of Scorpio and Sagittarius to catch M6 (M7 had already set behind a hill to the south—bummer), M69, M70, and M54, then all across the sky for M51, M101, M102, M13, M92, M15, back to Andromeda for a nice view of M31, M32, and M110 all prominent in the same field, M52, M103, M33, M76, and M34. I’d seen all these things before, but for most of them this was the lowest magnification I had seen them at, given that my binocular observations of them had mostly been with 15x70s. One of my favorite views of the night was M103 in Cassiopeia with NGCs 654, 663, and 659 in an arc below in the same field.

A little after 3:00 AM it was time for another goal: tracking down the outer giants. I had looked up the finder charts for Uranus and Neptune on Sky & Telescope’s website and logged their positions in my atlas. I found Neptune first, in Aquarius, using the Apex 127. Neptune was a very blue spark, and required 257x to appear non-stellar. Uranus, farther east in Pisces, was obviously non-stellar even at 64x. I also ran up to 257x on it, but the most pleasing view was at 175x. I had seen both planets before, but never as well, nor spent as much time on them as I did last night. Very strange to see giant Neptune as a tiny point of light in the mind-boggling darkness and immensity of space.

After observing planets I went back to the TS70 to continue the Messier survey. Logged M57, M56, M27, M45—absolutely stunning in the center of the field at low power—M72, M73, M2, M30, M75, M71—and old adversary from my early days with the XT6, but dead easy at low mag under dark skies—and M77. I tried for the faint face-on spiral galaxy M74 and suspected something there but couldn’t be sure. For a few these objects, including M72 and M77, I had to go up in magnification to pull them out of the skyglow or make sure they were not stars, using the 25mm (16x) and 17mm (23.5x) Plossls. I tried the 24mm ES68 but it was too heavy for the long cantilever from the mid-tube dovetail to the extended focuser tube of the TS70.

The last big show of the night was an upside-down kite shape rising in the east, with Jupiter at the top, Venus at the bottom, the thin crescent moon on the left, and Aldebaran on the right. I looked at the planets with the Apex 127 at 64x—the near-horizon seeing was bad but Venus’s crescent shape was well-defined, and Jupiter showed a couple of cloud bands and of course the four Galilean moons. Update: Pictures of this conjunction are posted here.

And that was it. The sky was rapidly getting brighter in the east, so we didn’t need artificial light to pack up. We pulled out at 5:25, went to Norm’s diner for breakfast, and I dropped Terry off at his hotel and went home for some badly-needed rack.

My final tally for the night was 8 new H400s, including NGCs 654 and 659; 44 Messiers, 42 of which I saw in the TS70; and 5 planets, including all four gas giants and Venus. Favorite observations were the flashing sky from over-the-horizon lightning, M81 and M82 in the same field in the Apex 127, M31 and both satellite galaxies in TS70, my best-yet views of Neptune and Uranus, and the dawn conjunction of planets, moon, and stars. Between dusk and dawn I observed five of the seven planets visible in a 5-inch scope, missing only Mars and Mercury (both were achievable, it turns out, I just didn’t try for them). It was a heck of a good night.

How did all the equipment perform? Stay tuned for the next post!

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Observing report: Binoculars on Mount Baldy

August 14, 2010

Thursday night my buddy Brian and I drove up Mount Baldy to do some casual observing. Brian probably wouldn’t describe himself as an amateur astronomer (yet), but I’m working on him. We’ve been talking for months about going out with binoculars and a planisphere and just spending some time learning the sky. When I got back from Uruguay I realized that Brian had been in town for a year and we hadn’t been out observing yet, so I started bugging him regularly. Thursday night, we went.

It was just by chance that Thursday night was the peak of the Perseid meteor shower; we were going out anyway and the meteor shower didn’t affect our decision one way or another. But it was a nice perk, and we both saw some excellent meteors up on the mountain. Not as many as we might have if we had gone for that purpose, because the best meteor watching is done with both eyes wide open, laying on the ground or on the hood or trunk of the car. Even binoculars cut out so much sky that you’re more likely to miss meteors than to see them if you’re scanning the sky with binos. That said, Brian did catch at least one through binoculars. Brian had along his 10x50s and I had my 10x50s, 15x70s, and SV50. We looked at just about every good target with all three instruments. Usually we’d find things with the 10x50s, kick things up a notch with the 15x70s, and go to the SV50 for a steady fixed view and sometimes for more power. It was a useful, easy-to-use set of instruments that I thought complemented one another well; my only regret was not bringing the eyepiece rack for the telescope mount, because I spent more time than I wanted fiddling with end caps when I was switching eyepieces on the telescope.

We started out facing south, down the mountain, toward Scorpio and Sagittarius. Those are two of the most recognizable constellations, Scorpio because it actually looks like a scorpion and Sagittarius because of the striking ‘teapot’ asterism. They’re also prime territory for deep-sky observing, with binoculars or telescopes of any size. Our first target was M7, just above the “stinger” of Scorpio. M7 is a BIG, bright cluster, and it looked pretty darned good even though Scorpio was down in the light dome over LA. M6 is right next to M7 and looks like its smaller sibling. From there we went up into Sagittarius, to M8, M22, and M24. M8 is the Lagoon Nebula, and M22 is the brightest globular cluster in Sagittarius. M24 is “not a ‘true’ deep sky object, but a huge star cloud in the Milky Way, a pseudo-cluster of stars spread thousands of light years along the line of sight, perceived through a chance tunnel in the interstellar dust”, according to its SEDS page.

At that point I was doing something else–switching eyepieces on the telescope, as likely as not–and Brian was just cruising with the 10x50s when he ran across another bright cluster. We identified it, and several other “discoveries” of the evening, by the following process: one person would find something in binoculars, and then hold the binos with one hand while getting a green laser pointer on target with the other hand. Then the other person would follow the line of the green laser to the target using his binoculars. That first time, the target was M11, the Wild Duck Cluster, one of the true gems of the summer sky. Other “discoveries” sent me scrambling for the star atlas.

By that point we had been facing south for more than half an hour and we needed a stretch and a change of pace. We hit M13, Epsilon Lyrae (the Double Double star), and M15 in the mid sky before settling down to face north. Our  first northern target was M31, the Andromeda galaxy. It was grand. We also spotted its two satellite galaxies, M32 and M110, without much trouble. By that time the Double Cluster had cleared the treeline to the north so we spent a few pleasant minutes contemplating that celestial showpiece. Then we just panned around Cassiopeia taking in all the good stuff. Even with binoculars, you can spot clusters in Cassiopeia faster than you can identify them, unless you already have them committed to memory, and we saw a lot more than we logged. Specific objects that we noted or looked up included the open clusters Stock 2, M34, and NGC 457. Our last two objects were M33, the Triangulum galaxy, and the Engagement Ring of stars around Polaris.

We wrapped up about 12:30 AM after a solid hour and a half of unhurried observing, during which time we had seen several asterisms, one nebula (M8), one identified double star (Epsilon Lyrae) and at least one unidentified by us, seven identified open clusters (M7, M6, M11, the Double Cluster, Stock 2, M34, and NGC 457) plus several more unidentified, three globular clusters (M22, M13, and M15), five galaxies (M31, M32, M110, M33, and our own Milky Way arcing high overhead), and a galactic star cloud (M24). So we had seen at least one of just about every class of deep sky object except for planetary nebulae and dark nebulae. If I’d been more target-oriented I would have remember M27, the Dumbbell Nebula, and then we’d have gotten a planetary as well.

But I wasn’t target-oriented. I was just there to have fun surfing the sky with a friend. I had a heck of a good time, and I think Brian did too. I’m already looking forward to the next time out.

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Mission 18: Diamonds from the Ring of Fire

February 27, 2010

Mission Objectives: Bright stars, Open clusters, Messier objects, Star hopping

Equipment: Sky map, Binoculars, Telescope

Required Time: 5-10 minutes per window

Related Missions: Ring of Fire

Introduction: Here on Earth, diamonds are found in the magma pipes that fed long-extinct volcanoes. Sometime in the distant future, the volcanic provinces of the Pacific “Ring of Fire” will be prime diamond-hunting territory. So it’s fitting that winter’s Ring of Fire is also full of diamonds, in the form of open clusters that decorate the winter Milky Way.

All of the clusters described here are within reach of 50mm binoculars, although most won’t show much detail at 7-10x. Even the smaller ones will start to differentiate in 15×70 binoculars, and all of them are stunning in telescopes of any size.

Instructions for M41, M93, M46 and M47: Go outside after dark, face south, and find Sirius. Use it to trace the “doggy” shape of Canis Major. M41 is the biggest and brightest of the clusters in this area, and it’s an easy catch right in the heart of the dog. I usually find it by centering Sirius in the field of view and then just sweeping down (south) through the constellation. It never fails to swim into view. If you’re having a hard time, M41 makes one corner of an elongated triangle with Sirius and a trio of brightish stars along the dog’s back.

After M41, the rest of the Messier clusters around Canis Major may seem a bit anticlimactic, but each has its own charm and they are all well worth tracking down. And there are even better clusters to come.

Although it is nowhere near as brilliant as M41, M93 is one of my favorites. It is small but fairly dense, and at low magnification its irregular shape makes me think of a silvery flame burning in the night sky. To get there, trace your way down the dog’s back to the bright stars Wezen, Adhara, and Aludra, which mark the dog’s hindquarters and tail. If you’re in doubt about which is which, note that these three stars form a right triangle with Aludra at the south end. From Aludra, a loose chain of bright stars trails east into the constellation Puppis. Sweep over and up, over and up, and you’ll see M93. If you get to a star as bright as Aludra, you’ve hit Rho Puppis (looks like ‘p Pup’ in the map above) and gone too far.

The last two in this window, M46 and M47, make a nice contrasting pair. From Sirius, scan east to find the stars that make the back of the dog’s head. I imagine these stars forming one end of a shallow arc that includes several bright background stars and ends on the paired clusters. If that doesn’t work for you, use Stellarium or the atlas of your choice to pick out intermediate stars to use as waypoints. A word of caution: this is a rich region of the sky, with loads of tiny faint clusters that aren’t marked on any but the most detailed maps. More than once I have been looking for M46 and M47 and gotten hung up in the wrong place. If you have any doubt about whether the clusters you’re looking at are the right ones, they’re probably not. One way to recognize them for sure is to note the differences between them; M47 is very sparse with a handful of bright stars in an irregular pattern, whereas M46 has many more stars that are more even in brightness, although none of them are nearly as bright as the most prominent members of M47.

Instructions for M35-M38: Now go to the north end of the Ring of Fire, to the bright star Capella. Use it to trace the 5- or 6-sided (depending on how many stars you include) ring of the constellation Auriga. The side of the polygon opposite Capella is formed by the long line from Alnath (technically in the neighboring constellation Taurus) to the next star clockwise. The clusters M37 and M36 are on either side of that line at the halfway point. Extend the line from M37 to M36 on to the west with a slight bend to the north to find M38. As with M46 and M47, this trio of clusters make an interesting study in contrasts. Here are my notes from Messier Marathon night:

  • M37: compact, dense with faint stars, very rich but dim
  • M36: smallest but brightest of trio, dominated by a few brighter stars
  • M38: intermediate between the other two in both richness and brightness

The first time I observed these clusters, I found M37 and M36 easily and then spent almost an hour trying to locate M38. It just wasn’t there! Then I checked the descriptions of the clusters and realized that I had actually been looking at M36 and M38. I’d been extending the line in the wrong direction. I backtracked and picked up M37 easily–an illustration of why it is useful to know what things ought to look like, and not just where they are.

The Auriga trio are nice clusters, but the fourth and final M-cluster in this window blows them all away. To find M35, trace down the body of the western twin in Gemini, from bright Castor to the swooping arc of stars that marks the outside ‘foot’. Just above the toe of the boot, in a right triangle with the last two stars in the arc, you’ll find M35, a big, bright cluster that rivals M41 in either binoculars or telescopes. If you’ve got a telescope, you can get a twofer–the small, compact cluster NGC 2158 is right next to M35 in the same field. It’s a tough catch in binoculars unless you’re under dark skies, but almost any telescope ought to show it easily. There’s a nice photo of the pair here.

Instructions for M44: I saved the best for last. M44, also known as the Beehive Cluster or Praesepe (“the manger”), is probably the second best cluster in the sky after the Pleiades. But it’s not as easy to find. The Pleiades have enough bright stars to shine out even in suburban skies, but the Beehive is an aptly named swarm of smaller lights. To complicate matters, M44 is located in Cancer, which has no bright stars.

I usually get to the Beehive from Gemini. Here are some methods that might work for you. My usual path is to draw a line from the extended arm of the western twin, through Pollux, and on in the same direction for about the same distance. Right now that line also intersects Mars, so you could cut your travel time by just drawing a line from Pollux, through Mars, to Praesepe. But that method is only going to work for a few days, maybe a couple of weeks at most, because Mars is on the move (compare its position in the map above with this shot from just a few weeks ago). Finally, if your skies are really nasty, you might try drawing a triangle from Procyon, to Pollux, to Praesepe. It won’t be a perfect equilateral, but it’s close; M44 is just above the point of what would be a perfect equilateral.

Or you could do what I often resort to when I’m in  a rush: find the region between the Gemini twins and Regulus, in Leo (just off-screen to the lower left in the image above), and just sweep around with binoculars or your finder. It’s pretty low-fi, but it’s never failed me yet.

M44 is a true showpiece of the sky, with dozens of stars of even brightness seemingly arranged in a net or grid. It can be seen with the naked eye under dark skies, but it really shines in binoculars. As with the Pleiades, it usually looks better in binos than in telescopes, although a short focal length, rich-field scope might have a wide enough field to show the cluster with some surrounding sky for context.

Coda: The nine open clusters in this  mission are just the tip of the iceberg. This section of the winter sky is littered with hundreds more. There are plenty of bright NGC clusters that rival or exceed many Messiers. The region around the ‘feet’ of the Gemini twins is an especially rich area to sweep with binoculars or a telescope at low power, whether you’re hunting for specific targets or just soaking up the view.

Spring is coming. Although the constellations of winter are high overhead at sunset, they are already starting their long slide toward the western horizon. So get ’em while you can.

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Observing Report: Messier Marathon!

February 14, 2010

Inspiration

My parents got me Harvard Pennington’s The Year-Round Messier Marathon Field Guide this past Christmas, and I have been obsessed with Messier Marathons ever since. I’d never run one; before last night I’d seen fewer than half of the Messier objects (54/110).

(A Messier Marathon is an attempt to see as many of the 110 Messier objects as possible in one night. Although Messier’s list has been around since the late 1700s, no one had realized that it was possible to see all of the objects in one night until the 1970s, and no one succeeded in getting all 110 in one night until 1985. Loads more info here.)

Pennington subverts a lot of conventional wisdom in the book. Before reading the book, I figured I might attempt a marathon some day after I’d seen all the Messiers and knew my way around the sky a little better. Pennington argues forcefully that running a marathon is the best way to learn the sky, build observing skills, and build confidence. In other words, it’s not something you have to work up to, it’s the way you work up to a good working knowledge of the sky.

Also, before reading the book I’d only heard of people attempting marathons in March and April when it’s possible to get all 110 objects. In Pennington’s words (page 3):

Some people go Marathoning only in March…. That is silly. The very next dark of the moon is the best time for you to run your first Messier Marathon.

Planning

One of my local clubs, the Pomona Valley Amateur Astronomers, was heading to Death Valley for a big star party this weekend. For various reasons, I was looking for something a little closer to home. Last month the PVAA star party was down at the Salton Sea, but we got clouded out after just a couple of hours. I knew that fellow PVAA member Ken Crowder was also looking for a closer spot and thinking of returning to the Salton Sea, and we planned to meet there yesterday evening. Ken was going primarily for astrophotography, and I was going to attempt a Messier Marathon.

Pennington’s Field Guide was my inspiration and how-to guide. I also wanted an all-sky map showing all of the Messiers that I could use as a roadmap. I found this one on WikiMedia Commons and printed out a color copy on 11×17 paper.* Finally, I used Stellarium to figure out where the horizon would be at sunset and sunrise, to determine which Messiers would be easy, which ones tricky at dusk and dawn, and which ones impossible. I used a black marker to draw the horizon lines on my all-sky printout, and used the marked-up map to figure out a search sequence.

In this I departed a bit from the Field Guide, which has built-in search sequences for every month of the year. These are good and helpful, but in places counterintuitive. Search sequences are critical for catching those objects that are only visible in short windows at dawn and dusk. For the rest of the night, it makes sense to work from west to east in strips and from south to north within a strip (because more southerly objects set sooner than northerly objects at the same right ascension, or sky “longitude”), but the exact order is less important. My decision to depart from the Field Guide sequence was not without consequence.

Strategies for Starting and Finishing

For the twilight rush, I wanted to start with M39, an open cluster near the bright star Deneb in Cygnus. It was the lowest Messier object in the sky at sunset, and thus the hardest to pick out of the twilight glow before it set. I wasn’t too worried about getting M39, because it’s fairly far north and would rise again a couple of hours before dawn. Still, it would be nice to get off to a strong start by picking it up the first time.

After M39, the twilight rush was full of galaxies: M74, M77, the Andromeda galaxy (M31) and its bright satellite galaxies M32 and M110, and fellow Local Group member M33. I was worried about these because galaxies are notoriously difficult in bright skies, and I’d never seen half of them, including the crucial M74 and M77.

At the other end of the night, I was anxious to see how many of the clusters and nebulae I’d be able to fish out of the sky around Sagittarius. This was a special concern because the area around Sagittarius and Ophiuchus holds the densest concentration of Messier objects in the sky–almost a third of the Messiers, in a patch of sky about as big as two outstretched hands. On top of that, they’d be rising just before sunrise. At best, I’d go into the Sagittarius region with 70-odd objects logged; the outcome of the marathon would largely depend on how well I fared that area, at the end of an all-night observing session, racing against the sunrise.

I knew from Stellarium that at least four objects were flatly impossible, because they would never be above the horizon without the sun: M72, M73, M30, and M2. Three more were pretty iffy; M55, M75, and M15 would be flirting with the horizon but deep in the morning twilight. A final three I felt pretty good about; M54, M69, and M70 are at the bottom of the Sagittarius “teapot” and I thought they’d be tough but doable. All told I figured the maximum possible outcome would be 100 objects definitely, 103 probably, and 106 at the very outside.

Setting Up and Getting Going

I got down to the Salton Sea just before sunset and found Ken set up in a parking lot near the campground. I set out my 6-inch Dob and 15×70 binoculars. I’m working on the Astronomical League’s Messier and Binocular Messier observing programs, and I wanted to bag as many Messiers as possible with both instruments (please be aware that the AL does not accept marathon observations for the Messier Club; nevertheless, running a marathon is still good practice and makes finishing the AL observations easier). I also brought a folding chair for seated observing at the scope, a tray table for maps and charts, a camp chair for visitors (which ended up holding the binoculars between looks), and a tripod for the binoculars. Normally I prefer to use the binoculars freehand, and in fact that is how I used them for most of the night, but when searching for tough stuff in the twilight it’s nice to be able to point them in one place and have them stay. I also brought along the basic creature comforts: warm clothing, snacks, and plenty to drink, both water to stay hydrated and energy drinks to stay awake.

The evening rush turned out to be surprisingly easy. M39 was an easy catch in both binos and scope. I couldn’t get M74 in the binos but it was fairly easy in the scope with averted vision. On the flip side, M33–a big, dim, face-on spiral galaxy–was easy prey for the binos and I didn’t try for it with the scope. In retrospect, I think I should have at least tried, but at the time I didn’t want to take any time out of the evening rush for such a notoriously tough catch.

Soon I settled into a rhythm. I used the all-sky map to figure out what to hit next and the Pocket Sky Atlas to figure out how to get there.** I tended to seek isolated targets with the binoculars first and then the scope. For objects in clusters or chains, I needed to be able to leave an instrument on a landmark I could get back to, so I worked out the star-hops with the scope and then chased them up in the binos.

The Realm of the Galaxies

Heading into the marathon, I was sweating the Virgo-Coma Cluster more than Sagittarius, for two reasons. I’d been through most of Sagittarius before, and it’s almost all globular clusters, which are usually easy. Virgo and Coma only have about half as many Messiers as the Sagittarius/Ophiuchus area, but they’re ALL galaxies, very tightly packed and with few bright stars for finding one’s way. Both the Field Guide and the Pocket Sky Atlas have special charts just for the Virgo-Coma “clutter”.

It turned out to be surprisingly nonproblematic. Perhaps it’s because I’ve been doing so many star-hops with binoculars from my driveway, but under the reasonably dark skies at the Salton Sea I found enough stars to guide me through the clutter. It wasn’t fast or fun–including 15 minutes off for a snack and a bathroom break, it took me almost an hour and a half to track down the 16 galaxies in that part of the sky–but I got them all. And all but one with the binoculars, after having found my path with the scope.

A Break

In any Messier Marathon in or around March, there is a spot after the Virgo-Coma Cluster when you’ve seen everything that’s above the horizon, and you might as well knock off for an hour or two while you wait for Ophiuchus and Sagittarius to crawl over the eastern horizon. In the quarter hour leading up to 2:00 AM I fished M12, M10, and M107 out of the dense atmosphere near the horizon, and then decided to call it for a while. I packed everything up and crawled into the car for a nap.

I couldn’t sleep until I had double-checked that I was on track, so I pulled out the all-sky map and started checking off targets based on my log. I had 73 down, but try as I might I could not find more than 36 unseen targets on the map. Somewhere I had missed something. And I had a nagging feeling that the one I had missed was one of Messier’s “mistakes”–a multiple star rather than a cluster. Fortunately, the Field Guide breaks down all of the Messiers by type and includes a special section on these. And there it was, M40, a double star in Ursa Major. I had completely missed it while sweeping up the Great Bear’s galaxies in the early evening. Fortunately it would be high in the sky for the rest of the night so I’d get another shot, but it illustrates the risk of not sticking to a strict, written observing program (M40 was on my map, I’d just cruised right past it).

Sorting that out took the better part of an hour. I planned to get back at it at 4:00. I set my alarm, closed my eyes, and…failed to sleep. Too keyed up, too anxious about Sagittarius. But I did rest.

Finishing

I got a bit of a late start. After rousing at 4:00, taking a biology break, and re-setting up all of my gear, I didn’t cross off M40 until 4:22. Then I knocked out M57, M56, M29, M27, and M71 in the area around Lyra and Cygnus–the last five objects outside of the Sagittarius snarl. I was back in the groove and went into Ophiuchus and Sagittarius crossing off an object every three minutes.

It wasn’t enough.

Having never seen a sunrise at the Salton Sea–and having seen only a couple of sunrises from any observing field–I had tried to guesstimate how late I could go from Stellarium. I knew the sun would come up at 6:40 AM, and I figured I could push through to about 6:00. Imagine my distress when at 5:20 I saw the sky getting bright in the east. I trucked on through the “steam” rising from the Sagittarius teapot, but I was getting desperate. Shooting up to Scutum and the “tail” of Aquila, the Eagle, I could not find M26 in the brightening sky. My final object was M11, the Wild Duck Cluster, which was an easy catch in binoculars at 5:38. I wanted to get it in the scope, too, but with so few stars showing in the sky I couldn’t figure out how to get there. I finally had to start at the other end of the Eagle, with Altair, and hop down the bright stars of the backbone. I got to the right spot, and couldn’t see a thing in the low power eyepiece. I had to boost the magnification to 120x to darken the sky sufficiently to pick up the dim outlines of the cluster, finally bagging it at 5:44. And that was it.

Results

I am pretty certain now that M55, M75, and M15 were too far down to be possible. I still think that M54, M69, and M70 might have been possible at the base of the teapot, but by the time I got to them they were history. I missed M26 and later realized that I’d passed by M23 in my Sagittarius blitz.

I ended the night with 98 objects. I got M74, M109, and M98 in the scope only, M33 in the binoculars only, and the other 94 with both instruments. I also wrote down a one-line description of each object. As stated above, marathon observations don’t count for the Messier Club, but it was still useful to scribble down a brief description. It will make re-observing the objects easier and more interesting, since I’ll be able to compare my thoughts from a more leisurely look to my brief impressions on marathon night. And it is nice to have a physical memento of the night; I’ve reread my notes a couple of times already and have a feeling that I’ll return to them a lot in the future.

On one hand, I am frustrated that I ran out of time. M23 and M26 should have been easy prey–they were way up in the sky compared to some of the other home-stretch targets–I just never got to them. A rookie mistake, fairly small in the big scheme of things, but it kept me from that magical three-digit number.

On the other hand, 98 objects is still a great score for my first marathon, especially an “off season” marathon in which fewer than 110 objects were possible to begin with. It was a huge confidence builder and a heck of a lot of fun. I learned a ton about what works and what to avoid. And I’ll definitely be back for more.

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* The printable version of this chart is now on the “Messier Marathon tools” page on the sidebar, along with a streamlined checklist for marathon night and other goodies.

** It occurred to me after I wrote this that it might sound a little odd. On one hand, I have been singing the praises of the Year-Round Messier Marathon Field Guide, which includes both a search sequence and charts for each object. On the other hand, I used a free star map to figure out my sequence and the Pocket Sky Atlas for actual finding. So you may be wondering if I used the Field Guide from the field at all.

The answer is that frankly I didn’t use it that much. The Field Guide charts are great, especially for people who don’t have an all-sky atlas or who  are looking for one-stop shopping for the Messiers. But from working on the AL Binocular Deep Sky and Urban Observing lists this spring I’ve gotten used to using the trio of (1) an observing list, (2) the PSA, and (3) a logbook for taking notes. I have used the Field Guide once or twice in the field, but I’m so used to the PSA now that it just feels more reflexive to reach for that instead. And I knew that on marathon night I needed to use what worked best for me.

That said, I did use the Field Guide to find the one that I’d missed (M40), to double-check that I’d gotten everything in the Virgo-Coma clutter (even though I used the PSA for the actual slog), and to work out a couple of the twilight rush star-hops. The Field Guide was most important for giving me the inspiration and confidence to tackle a marathon in the first place, and I definitely wouldn’t have been without it  by my side. It’s a great book and I recommend it to anyone with an interest in deep sky observing.

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Shedloads of good stuff from Jay Reynolds Freeman

January 7, 2010

I just stumbled across a several troves of useful and frequently hilarious articles by Palo Alto-based amateur astronomer Jay Reynolds Freeman, and I am posting the links for your entertainment and edification.

I decided to hunt down more of his writings after reading “Refractor Red Meets the Herchel 400“. The Herschel 400 is one of the most difficult observing clubs administered by the Astronomical League; many observers would say that tackling it with anything less than a 10-inch scope would be a doomed enterprise. And yet Freeman did the whole list from Palo Alto, within the San Francisco light dome (!), using the titular refractor, which has a scant 55mm of aperture (!!!). To put this  in perspective, the most popular scopes for beginners are 6-8 inch (150-200mm) instruments; my little Mak has an aperture of 90mm; and most good-sized scopes have finderscopes with 50mm of aperture. I would not have thought it possible to do the Messier list with a 55mm scope, let alone the Herschel 400; it is akin to finding out that someone circumnavigated the globe on a surfboard.

There is a nice batch of his articles here at Observers.org, most of which are pitched at beginners. The standout is “Recommendations for Beginning Amateur Astronomers“, which is available at several places on the net in several versions. If you own, want to own, or think you may ever own a telescope, read it right now; most of the advice on choosing and using a scope that you will ever read will be a less funny, nth-generation rehash of points made more economically and entertainingly in this piece.

The second and even bigger batch is at Cloudy Nights. I particularly recommend the article “10,000 Objects Logged“, which gives a quick and inspiring look back at several decades of observing. Freeman started out with about the humblest equipment possible, and still achieved more than most people probably think is possible:

My observing program used to be simple: I only had a 7×50 binocular. With good dark adaptation, high transparency, and maniacal persistence, I managed to find all the Messier objects with it.

Keep in mind that this is the same Messier list that I am currently tackling, with some exertion, using a 6-inch telescope.

Now, you might think that a guy who has done the Messier list with 7×50 binos and the Herchel 400 with a 2.2-inch telescope would be a champion of small aperture instruments. And he is, within limits. But here’s what he has to say on small versus big:

I don’t know where the idea came from, that small telescopes get used more than large ones, but as far as my own experience goes, that notion rates with flat-earthism and the luminiferous ether as unadulterated nonsense. If I could have only one astronomical instrument out of all the ones I have owned, it would without question be my Celestron 14.

I think it is worth pondering the fact that the same person who has logged thousands of observations on a telescope the size of a piece of furniture then took time to do a few hundred on a telescope the size of a rolling pin.

It is worth pointing out that Freeman has done serious technical work in astronomy, too. In that vein, and because it is one of my favorites of his, the last article I will recommend is his review of the movie Contact. That one is at his astronomy homepage, which has many but not all of the articles posted in other places, and quite a few more besides. His reflections on the Apollo program are fascinating and moving.

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Mission 14: Three Astronomical Treats for Naked Eyes, Binoculars, and Telescopes

December 21, 2009

Mission Objectives: Bright Stars, Constellation, Open Cluster, Nebula

Equipment: Free star map, Naked eye, Binoculars, Telescope

Required Time: 10 minutes

Related Missions: Cassiopeia and the Double Cluster

Introduction: I’m in Oklahoma for the holidays. My best observation here so far didn’t require any optical aid at all. Remember last month when I was skunked in my quest to view the young crescent moon within 40 hours of new? On Thursday, December 17, the night after I got into town, I saw the 38-hour-old crescent moon in the western twilight over Oklahoma City, thus fulfilling the last requirement I had left for the Astronomical League‘s Lunar Club. I e-mailed in my completed log sheets on Saturday.

Instead of bringing a little scope with me, I borrowed back the one I had loaned to my brother. It’s a Synta MC90, another 90mm Maksutov-Cassegrain, but unlike my other little Mak it’s a short focal length, widefield scope. I got it out last night to show my nieces the waxing crescent moon, Jupiter, and the Pleiades.

Instructions: Speaking of the Pleiades (M45), they’re one of the best astronomical treats for a clear winter evening. Finding them is easy: look to the east after dark, and find a little knot of stars that looks a bit like a cooking pan. This is not the Little Dipper, although you’d be surprised at how many people think so on first spotting it. If you have a hard time finding the Pleiades, look for the 3/M/W of Cassiopeia, head past the Double Cluster to Perseus, and follow the lower of the two sweeping lines of stars that make up that constellation; the cluster is just off the end of the line. The Pleiades are pretty to the naked eye and probably best in binoculars. All but the widest-field scopes will have a hard time putting the whole cluster in the eyepiece, and even if you manage it, it’s prettier if you can see the cluster as a cluster, with a little open space around it. So this is one of those times that–in my opinion–binoculars trump a telescope.

If you have found the Pleiades, drop straight down (east) to find a V-shaped association of stars. These are the Hyades, another open cluster, in the constellation Taurus. One leg of the V is anchored by a big red giant star, Aldebaran, whose color is obvious even to the naked eye. You can pan around the Hyades with a scope if you like, but the cluster is so big that it really demands binoculars; binos fall right into the sweet spot of putting a lot more stars in your eyes without overly narrowing the view or getting you lost.

From the Pleiades, on to the Hyades, and farther on east you come to Orion, the most magnificent constellation in the sky. Find the three bright stars in a line that form his belt, and then three dimmer stars in another line that form the sword hanging from the belt. The middle of the three stars in the sword is not a single star at all. Rather it is M42,  the Great Nebula in Orion, a vast cloud of gas and dust, dozens of light years across, which is illuminated by the bright young stars burning within.

M42 is what I call a total object: like the moon, it looks good no matter what you use to look at it, and the more you look, the better it gets. With the naked eye, the nebula it is a faintly fuzzy star at the heart of a striking and majestic constellation. With binoculars, you’ll see a bit of nebulosity set amidst the rich starfields of Orion’s sword. In a small telescope, the full glory of the nebula starts to unfold, with glowing streamers of gas and dust spread out like an eagle’s wings. The central star will split apart into a group of four, called the Trapezium. Pour on more aperture and magnification and the view just keeps getting better. If the skies are clear and steady you may pick up a couple more stars in the Trapezium, and the surrounding clouds of gas and dust will start to look like clouds, with delicate knots and swirls.

And on it goes. You are not going to exhaust M42, not in a lifetime of observing. People with telescopes that require large trailers for transport, who have seen M42 literally thousands of times in their observing careers, still gaze into the heart of the nebula for minutes and even hours at a time. The bigger the scope, the darker the skies, the longer you look, the more there is to see.

But, hey, don’t think that if you don’t have a monster scope it’s not worth looking. Remember, M42 is a total object; it looks good at any scale. If the thought of setting up a scope in the cold and dark does not appeal, at least pop outside for a five minute session with binoculars. Make it a present to yourself.

Happy holidays!