Archive for January, 2010


The moon in 3D!

January 27, 2010

Last month I sent in my completed logbook for the AL Lunar Club to Steve Nathan, the coordinator for that club. We struck up a conversation and he shared the above image and some information about it (with permission to post):

The Moon image is attributed to L. M. Rutherford.  The images were take on Sept. 15 and Nov. 13, 1864.  His original negatives were copied by many (!) 3D stereo card publishers for decades…into the early 1900’s.  Other phases of the Moon were also shot in 3D, but all took advantage of the libration effect. Similar 3D images exist for the planets, sunspots, meteors, etc.; all with limited, to no 3D effect. However, somewhere around here I have Neil Armstrong’s famous lunar bootprint…in 3D! (FYI: much of the NASA lunar program photography was done in 3D).  Intriguing, eh?!

If you don’t have a stereo-viewer (I don’t), don’t click on the image (leave it at column width), hold your head back at least a foot and a half from the screen (farther is easier), cross your eyes until the moons double up and then merge the two in the middle to make one bright 3D moon between the two flat ones.

Earlier I had asked if two cameras had to be widely separated geographically to get the stereopair. For making stereopairs of Earthly objects, two photos must be taken with the camera in slightly different places to simulate the separation between our eyes. Since the moon is a quarter of a million miles away, it seemed logical that you’d need the cameras to be as far apart as possible. But as you can read above, the two shots were separated not in space but in time. Steve wrote:

Libration alone will do the trick, the object of interest (the Moon) presents two different views of itself to the observer; increasing the baseline/camera separation would be redundant.

Libration is the “wobbling” of the moon over time as seen from Earth, because of the complex geometry of the Earth/Moon/Sun system. Go here for a more complete explanation.

Pretty darned cool; there is absolutely no reason I couldn’t give this a whirl as soon as the clouds clear out. If I get anything, I’ll post it here. In the meantime, here’s another version of the stereopair that I cleaned up a bit in GIMP. I like the sepia-toned classic version as well; use whichever tickles your fancy.

Finally, many thanks to Steve for sharing the image and the information!


Mission 16: MARS!

January 26, 2010

Mission Objective: Planet

Equipment: Telescope

Required Time: 10 minutes

Related Missions: Ring of Fire

Instructions: Go outside after dark, face east, and look for a red star. It may help to get to Mars by way of the ring of bright seasonal stars that are also climbing the eastern sky on winter evenings.

On January 29, Mars will be at opposition, when it is directly opposite the sun from us. That means (by definition!) that it rises at sunset and sets at dawn, just like the full moon–in fact, you could say that the moon is full when it is at opposition. So you’ll have to wait a while after sunset before Mars will be very far up the sky. The best time to observe is when Mars is at the zenith and you’re looking through the least atmosphere possible, which happens around midnight.

For observers, the oppositions of Mars vary more noticeably than those of any other planet. The orbit of Mars is considerably more elliptical than that of Earth, so sometimes when we pass each other we are very close, and sometimes not so much–the Earth-Mars distance at opposition (when Mars is directly opposite the sun from us, and therefore as close as it is going to get on that pass) varies from about 35 million miles to something like 60 million miles. Right now we’re at the long end, and 2012 will be about equally as bad. The next close approach is 2018.

Still, Mars is as good as it’s  going to get for two years, so you might as well have a look. Last night I was able to see tantalizing detail at 92x in my six-inch reflector using a 13mm eyepiece. I put in a Barlow lens to double the magnification. Using that and the 3x optical zoom on my Nikon Coolpix 4500 digital camera, I got the shot at the top of this post, which is comparable to what I could see at the eyepiece. Here’s a labeled version:

The telescope inverts the image by 180 degrees, and I didn’t bother to flip it. Presenting planets southside up is pretty much the standard for solar system astrophotography, to the extent that the map of Mars in the December Sky & Telescope had the south at the top. That map is by expert solar system imager Damian Peach, and I used it to identify the features shown above. If you want to see some really mind-blowing shots of Mars and the other planets, check out Peach’s website. My Mars shot is pretty similar–in terms of part of the planet shown, not clarity!–to the second photo from the top on this page.

That’s all for now. Go explore the red planet. If you don’t have a scope or it’s too cold to set one up (one guy on Cloudy Nights posted a Mars shot he took on a night when it was -36C at his place in Russia!) at least go outside and have a look. Spirit and Opportunity are still up there, six years on. If you do see Mars, throw ’em a friendly wave, or maybe a salute. They’re doing us proud.


Observing Report: binoculars vs. cloudy skies

January 20, 2010

70mm of EPIC WIN -- times two!

Contrary to popular belief, it does rain in southern California. We’re in the middle of what is projected to be a solid week of rainy weather. Today we had thunderstorms and a small tornado even came ashore in Orange County. So I hadn’t planned to get any observing done until after this coming weekend.

Rather, I should say that I hadn’t counted on getting any observing in. But I had hoped that there might be some breaks in the clouds, and I had planned accordingly. The point of generating all of the AL observing club logbooks was to have all my ducks in a row when the sky cleared up this rainy season (I can’t bring myself to call it “winter”, and we really only have two seasons anyway, rainy and dry).

By the way, it may look like I’ve gone completely mad for AL observing clubs, with six active projects. But there’s a lot of overlap; some observations for the Messier and Deep Sky Binocular clubs also count for the Urban club, and Deep Sky Binocular work is basically observing the brighter NGCs that never made it into the Messier list, so except for the Galileo and Lunar II clubs, all of my observing projects involve hunting down faint fuzzies. And they all can be done with binoculars, at least to a point, although ‘nokks are only required for the two clubs with ‘binocular’ in the title.

ANYWAY, this evening the clouds cleared out for a bit so I grabbed my observing kit and headed out into the driveway to hunt for goodies. What’s in my binocular observing kit? Glad you asked!

  1. My ‘nokks of choice, Celestron SkyMaster 15x70s. These are big, and they really gobble up the photons. The views are sharper when they’re mounted, but I prefer the freedom of handheld scanning, and that’s how I use them most of the time. If I’m going to use smaller binoculars on a given evening, I have to do so before I look through these; going back to 50mm of aperture is like having someone shut off the lights. Huge bang for the buck, but if you’re going to freehand them, get a wide padded neck strap instead of the shoelace guillotine that comes included.
  2. Sky & Telescope’s Pocket Sky Atlas. I love, love, love this atlas. It’s small enough to hold in one hand, spiral bound to lay flat or fold over in the field, easy to read with a red flashlight, conveniently organized…with this atlas, my 15x70s, and reasonably dark skies, I can ‘nokk off DSOs about as fast as I can look them up on the charts. In the city I can’t always see the faint fuzzies, but I can always get myself to the place in the sky where they would appear if I wasn’t under the LA light dome.
  3. Notebook. I use a hardbound 8×5 off the bargain rack at Borders, but anything would do, even a blank piece of paper. At the top of the page for each observing session I note the date, location, and sky conditions. Entries include time, instrument used, target,  and a brief description. I transcribe everything into my AL logbooks after I come back inside, because its easier to do that than juggle four floppy 8×11 notebooks in the field.
  4. Red flashlight. Mine is a Mini Maglite with the window painted over with a double coat of red nail polish. I wear it around my neck on a lanyard so it’s always to hand. Bright enough to let me use the atlas and record my observations without trouble, small enough to fit in my teeth when I’m laying on my back and two-handing the atlas overhead.
  5. Writin’ iron. I use the cheapest stick pens that money can buy, so I don’t have to worry about breaking or losing them, but whatever you like will do.
  6. Hooded  sweatshirt. Surprisingly useful. Not only keeps me warm, I can stash the binocular lens caps in one pocket and my pen in the other. The biggest benefit is being able to pull the hood around my face like a cowl to block out stray light and improve my eyes’ dark adaptation. This makes a BIG difference in seeing faint stuff I would otherwise miss. Patience, and knowing I’m looking in exactly the right place (thanks to the atlas) are the other two legs of this triad.
  7. Towel or folding chair. Depending on how my targets are. If low in the sky, I may choose to sit in a folding chair. If high in the sky–where I prefer to work, both for ergonomic reasons and because things look the best when you’re looking straight up, through as little atmosphere as possible–I lay a beach towel on the car and lay back against the windshield. The towel keeps me warmer than I would be otherwise and keeps me from scratching up the car.

That’s it. For  walking out the door, I’ve got the sweatshirt on, binoculars and red flashlight both hanging from their neck straps, pen in my pocket, atlas and notebook in one hand, towel or folding chair in the other. I’m outside in one trip, and observing about 5 minutes after the  mood strikes.

That comes in handy on nights like tonight; between 5:30 and midnight I was out four times, because the sky was clear four times and cloudy three times in between. It would not have paid to set up a telescope, and I would not have felt comfortable doing so considering the amount of moisture  still falling down out of the trees–when the slightest breeze hits the tall palm in my front yard, it shakes itself like 60 feet of wet dog. So it was ‘nokks or nothing, which suited me just fine because I’ve been on a serious binocular observing bent lately.

I spent the first session ‘nokking off some easy Messiers. Nothing new, all things I’d already seen and logged from the Salton Sea and just needed to dupe for the Urban Club. Still nice to check those off the list.

The rest of the sessions I was hunting clusters. I’ll give the full run-down on how I do this in another post. Suffice to say that by the end of the night I had logged 24 DSOs, including 15 objects that I’d never seen before. Some of them were just gorgeous–there is a nice run of little clusters off the feet of Gemini that must been seen to be believed. Plus I got in some sweet views of the moon and had a quick peek at Mars and Saturn, too.

Now it’s late and I’m bushed, so I and my victory energy are going to bed. Catch you on the flip side.


Mission 15: Ring of Fire

January 16, 2010

Mission Objectives: Bright Stars, Constellations

Equipment: Naked eye

Required Time: 2 minutes

Related Missions: Three Astronomical Treats for Naked Eyes, Binoculars, and Telescopes

Introduction: It’s a new mission for a new year. New stars are in the skies, and it’s the perfect time to start exploring the heavens–for the first time if you’re new to this, or exploring it again if you’re an old hand. This mission requires no prior knowledge, experience, or equipment; it’s just about getting out and getting acquainted with the night sky.

Instructions: Go outside after dark, face southeast, and find three stars in a straight, vertical line. These are the stars of Orion’s belt. They are flanked on either side by twin bright stars of roughly equal brightness but different color. On the left is Betelgeuse, an enormous red giant that appears yellow to the naked eye. On the right is Rigel, a blue-white supergiant.

Follow the line made by the belt stars down to even brighter Sirius. Sirius is the brightest star in Earthly skies, but it’s a not a giant or supergiant like Betelgeuse and Rigel. In fact, Sirius is a main-sequence star, a little less than twice the diameter of the sun, but about 26 times as bright. By comparison, Rigel is about 40,000 times as bright as the sun. But Rigel is 773 light years away, whereas Sirius is only 8.6 light years from us–the fifth closest stellar system to our own. Sirius, the Dog Star, is the chief star in the constellation Canis Major.

From Sirius, hang a right-angle left turn and head on to Procyon, “before the dog”, so named because it rises just a few minutes before Sirius from mid-northern latitudes. The small and otherwise dim constellation Canis Minor has little else to recommend it, and Procyon serves mainly as a celestial landmark.

Farther left still, and farther up in the sky, are the twins, Castor and Pollux, at the head of the constellation Gemini. If you have trouble keeping them straight, remember that “Castor is close to Capella, but Pollux is in proximity to Procyon”.

Speaking of Capella, it’s the very bright star directly toward the zenith from Castor and Pollux. It’s a brilliant gem in a ring of prominent stars that mark out the constellation Auriga, the Charioteer (this is not the big ring marked in red on the diagram above, but the much smaller blue-white ring on the upper left).

To the right of Capella is Aldebaran, the burning red eye of Taurus, the Bull. Aldebaran means “the follower”, because this star rises after the Pleiades, which it appears to chase from horizon to horizon (to trace that line, see the previous mission). Aldebaran is an orange giant, meaning that it has exhausted the hydrogen in its core and moved off the main sequence. Without the outward pressure of radiation from hydrogen fusion to prop it up, the core of the star is compacting under gravity and heating up. When it gets hot and dense enough to start fusing helium, Aldebaran will bloat into an immense red giant, like its neighbor, Betelgeuse.

And speaking of Betelgeuse, it lies in the middle of the great circle described by Rigel, Sirius, Procyon, Castor and Pollux, Capella, and Aldebaran. I call it the Ring of Fire–nowhere else in the northern sky is there an equal concentration of bright stars.

Below and to the left (east and north) of the Ring of Fire is Mars, which will be at opposition–opposite the sun, and at its closest approach to Earth–in a couple of weeks. The orbit of Mars is more elliptical than that of Earth, and this will not be one of the better oppositions, but it’s still the best look at the red planet that we’ll get for another two years.

What’s next? This mission was just a lightning run through the bright stars of winter. Their respective constellations are packed full of beautiful targets for binoculars and telescopes, and we’ll look at some of those in future missions. If you’re impatient to get started, download this month’s The Evening Sky Map, haul out your optics, and happy hunting!


Moon bling

January 14, 2010

As I related in an earlier post, on Thursday, Dec. 17, I made my final observation for the Astronomical League’s Lunar Club. I e-mailed in my completed observation log a couple of days later. Yesterday my loot came in the mail: a certificate and pin.

I felt a sense of accomplishment (and, in the spirit of full disclosure, relief) on the evening that I made my final observation, and it was nice to send off my log, but there’s something extra special about getting the official certificate and pin. You know why they give these things out? I think it’s for the same reason that judges wear black robes and baseball fans doff their caps for the national anthem. We are a symbolic species, and on some subconscious level that stuff works, whether we want it to or not.

The certificate is going on the wall over my astronomy bookshelf, and the pin is going on the Kepler mission cap I got at the JPL gift shop last week (I still need to blog about the JPL tour–so much to do!). There are many like them…but these are mine!

And I want more. I’ve been plugging away at the target lists for the Messier Club and Galileo Club, and tonight is the start of a new lunar cycle so in a couple of nights I can get back to my observations for the Lunar II club.

Good luck with your own observations. If you’re not doing a formal observing program, give it some thought, working through one is challenging, rewarding, and fun. The complete list of AL observing clubs is here, and there are lots of other observing programs out there in books, magazines, and on the web.

More missions coming soon!


Observing Report: Salton Sea…and Claremont

January 10, 2010

Best-Laid Plans

Since I moved to SoCal and joined the local astronomy clubs, I have done lots of public outreach events and moon and planet parties, but until this past weekend I had never been to a star party. Moon and planet parties are easy; set up your telescope wherever there are people and show them the bright stuff. Light pollution is no problem. Star parties are a different story. If you want to see the faint but beautiful clusters, nebulae, and galaxies, you have to have dark skies.

Both of my local clubs have star parties regularly, but until now there has always been some scheduling conflict or another that kept me from going. But I finally had a shot last Saturday, January 9. The Pomona Valley Amateur Astronomers were going to the Salton Sea, a big saline lake out in the desert south of Joshua Tree.

I spent last week planning the trip, making a pack list (which I need to post sometime), and especially figuring out an observing list. The AL Messier Club is my main observing goal this season, and I am freshly armed with Harvard Pennington’s extremely useful Year-Round Messier Marathon Field Guide, which has finder charts and eyepiece sketches for all 110 Messier objects.

Inspired by Jay Reynolds Freeman, I decided to get as many Messiers as possible with my 15×70 binoculars; those observations would count for both the AL Binocular Messier Club and the regular Messier Club. About 20 or so Messiers are currently too close to the Sun to be observed right now, leaving about 90 viable targets. Knowing how unpredictable observing can be, I decided that my conservative goal would be 20. But I secretly hoped to bag quite a few more, maybe 50 or beyond, which didn’t seem unreasonable if I could just stay up all night. We had some nice clear nights last week, and I was sorely tempted to stay up observing from my yard on a couple of evenings, but I decided to save my energy for the big push Saturday night.


Saturday I got up early, got packed, took care of some household chores, at lunch, and tried to get a short nap before I hit the road. I was too keyed up to sleep, but I at least chilled out a bit. I got on the road at 2:00 so I could get to the State Recreation Area campground, where we were meeting, in time to set up before sunset.

I was uneasy on the drive out. The sky was full of cotton, from horizon to horizon. Not low, scudding clouds, but the high cirrus-like stuff. Low clouds I don’t worry about so much; they come and go so fast that it is almost impossible to predict what is going to happen in 20 minutes or 20 miles away. They also tend to have breaks now and then so you can still get some observing done through the sucker holes. High clouds tend to stick, and the spaces between them are usually filled with enough haze to make observing difficult or impossible. As far as I could see, all of SoCal was under a vast tent of high clouds.

A couple of times I almost turned back, but as Timothy Ferris said of observing in Seeing in the Dark, you can’t catch any fish if you don’t get your line wet. And who knows, sometimes things do clear off.

The Sea and the Stars

I got to the campground and found a handful of other PVAA members setting up. Someone had talked to the park ranger, who said that daytime clouds often cleared off after dark. I set up my gear, scarfed a quick supper, and spent about half an hour watching birds. The Salton Sea is a major mecca for shorebirds and birders alike. There were dozens of night herons and a handful of great horned owls nesting in the trees near our campsite, and down at the shore I saw egrets, pelicans, about a trillion gulls, and little shorebirds of more makes and models than I can identify. Sunset was gorgeous, flaming pink clouds behind purple mountains, all reflecting off the glassy surface of the sea, interrupted only by the wheeling and gliding of hundreds of birds.

But enough of that rot! What about the stars? Well, against all odds, they started coming out. First Jupiter, then Deneb in the northwest, then Capella, Betelgeuse, and Procyon in the west, and so on until all of the seasonal constellations were out. The sky wasn’t perfect–there was a thin high haze that dropped the transparency a bit, and the odd plank of  cloud interrupted one or another view from time to time–but in general they were pretty darned good. Looking straight up, I could see the Milky Way easily and the Andromeda galaxy with averted vision, which is my usual test for decently dark skies. I made a couple of sketches for the AL Galileo Club and then started knocking off Messiers.

It was a doomed enterprise. The first few were easy, and I took the opportunity to look at a few showpiece objects through other people’s scopes, and show off stuff in mine, but the longer I hunted, the fewer things there were to see. The clouds were creeping back in. Soon the entire western half of the sky was blocked off. Orion was still prominent, but the haze gradually increased until every star looked like a nebula.

We pulled our chairs into a circle and had a good chat, but by 9:00 it was clear that the sky wasn’t getting any better, and according to the weather forecast, it wasn’t going to get any better. We reluctantly packed it in. I had come prepared to spend the night, but I expected to spend it observing. With nothing to hold me there, I hit the road back to Claremont.

Climbing Mount Improbable

It was not a fun drive back. I’d gotten a measly eight Messiers with binoculars, and one more with my 6″ reflector. That was M29, which was pretty far down into the light dome over LA. And speaking of the LA light dome, for the whole drive back I was under it, the evil pink glow of urban sprawl bouncing off a solid deck of cursed clouds. And curse them I did, vigorously and continuously.

I was holding out a secret hope. Sometimes Claremont is totally socked in, but up on Mount Baldy, less than 15 miles from my house, it’s totally clear. I had already planned to stay up all night and I had all my gear, so why not? I’d run up Mount Baldy and just see. I figured it would be completely either/or. Either the clouds would be high enough to go over the mountains, in which case I’d get nothing, or the clouds would stop on the flanks of the mountains, in which case they’d be blocking the city lights and the mountain would be even darker than usual.

Of course, it was the former. Doubly defeated, I drove home. Got in after midnight, stowed about half my gear, and got ready for bed.

Just To Be On The Safe Side…

I was just about to hit the sack when it occurred to me to wonder if I’d locked the car. I’m forgetful, and sometimes don’t, especially if it’s taken me several trips to unload. So I padded out to the driveway to check. The car was locked after all. More importantly, the sky was almost completely clear. In the 20 minutes it had taken me to unload and shut down, the edge of the cloud deck had come east and cleared my neighborhood. There was Orion, Taurus, Canis Major!

Now, I had just rocked through the open clusters of the Big Dog a few nights ago with my reflector, and I knew they’d be easy prey for with the 15×70 binoculars, and I was up anyway, and I needed a win. So I pulled on some sweats, grabbed binoculars, atlas, logbook, and red flashlight, set up a folding chair in the middle of the  driveway and got to work.

I quickly knocked off the Pleiades, M45, which would have been an easy catch at the Salton Sea but which I’d passed over in favor of harder targets. I ‘d figured I could pick it up later, any time the sky was clear. There on the driveway at one in the morning turned out to be just the “later” I needed. Then M41, a bright and easy cluster in the heart of Canis Major. Then M44 and M67 in Cancer, and I was off and running.

I didn’t find everything I looked for. The clouds were gone but the normal LA light pollution was still there. The effect of magnification is to spread out the background sky, thus making it darker, so to some extent you can fight light pollution with magnification. This works well with open and globular clusters, which are balls of stars in and around the Milky Way. It doesn’t work as well with nebulae and galaxies–magnification can actually hurt, by spreading out their otherwise concentrated light until it’s lost in the skyglow. And increasing the magnification is not an option with standard binoculars. I bagged every cluster I tried for–which is every one that was up at that hour–but failed to get even a single galaxy. I think that will require another trip up the mountain.

Still, in a little over an hour, I’d bagged a dozen Messiers with the binoculars, including a couple, M40 and M48, that I’d never observed with any instrument. That brought me up to 20 for the evening with binoculars, and 21 total, just past my original goal for the star party. I stayed up a little longer to get M5–big, bright and easy–and even longer for M68, which was devilishly difficult in the LA light pollution, but ultimately doable, and called it a night.

I’ll post directions for finding most of these, along with some tips and tricks for observing them from the city. The biggest hurdle is just getting out and trying. In the end, I had a great night and a lot of fun. I enjoyed the company of my fellow astronomers at the Salton Sea, and it was nice to go to bed, finally, full of victory energy and not just hatred for the clouds.

Stupid clouds.


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, 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.


Observing and photographing the moon with binoculars

January 5, 2010

I’m always saying that you can see craters on the moon with binoculars, but I suspect that many people don’t believe me. So here’s the proof.

Here’s a raw, completely unretouched image I took on the evening of January 2nd.

The same image, cropped and lightly sharpened using “unsharp mask” in GIMP.

Then converted to grayscale, which gets rid of the annoying coloration on the limb. That’s chromatic aberration or CA, which is present in any optical system that uses lenses to collect light. The problem is that different wavelengths of light have different refractive properties, so a lens can never bring all of the wavelengths to focus at the same point. In telescopes and binoculars, the out-of-focus wavelengths at either end of the spectrum make yellowish and purplish halos around bright objects, even in daytime. You can knock down the CA to unnoticeable levels by using combinations of very expensive glass in the lenses, as in apochromatic refractors or APOs, or with anti-fringing filters, but it can never be completely eliminated.

Here’s the final version of the image, in which I tweaked the brightness and contrast using the “Curves” function in GIMP. This lets you selectively brighten and darken pixels of different values, and I use it on almost everything.

So what have we got? Well, first of all, there are dozens of craters in view. Now here I have to confess that looking at these photographs is cheating, a bit. The digital images are magnified by the camera and blown up to a convenient size on your screen, so you can pick out a LOT more detail from these pictures than you would out in the dark with the binoculars alone, even if they were mounted.

Nevertheless, the camera couldn’t capture detail that wasn’t there, so all of this was at the eyepiece, and how much you might get would depend on your visual acuity and level of experience. Experience counts, and the more experience you have, the more you realize that it counts. A big part of one’s growth as an observer is learning to see, which largely means cultivating the patience that it takes for your eyes to suss out the subtle details present in whatever you’re observing.

I decided to take this picture because I was really blown away by the sharpness of the features along the terminator, especially Mare Crisium and the nearby craters. Like all of the maria or lunar seas, Mare Crisium is an impact basin that was flooded with basalt; unlike most of the other maria, Crisium actually looks like a giant, flooded crater. Just north of Mare Crisium is the ancient crater Cleomedes, which you might easily pass over when it is less dramatically lit. Farther north along the terminator, the flat-floored crater Endymion is a black pool of shadow.

A final confession. Despite the title of this post, I didn’t take this photo through binoculars. I took it through the 9×50 finderscope on my big telescope. A pair of commonly available 10×50 binoculars would offer the same angular resolution and slightly more magnification, and would therefore show you even more–especially if they were solidly mounted. Here is a much better picture from a couple of years ago that I really did take through 10×50 binoculars.

Okay, so you can get serviceable pictures of the moon using a point-and-shoot digital camera and cheap binoculars. But how?

First, mount the binoculars on a tripod to keep them steady. Ideally, once you get them aimed and focused you won’t have to touch them at all while you’re taking pictures, except to periodically re-aim them as the moon crawls across the sky.

Second, use a digital camera that offers optical zoom instead of electronic zoom, and use as much optical zoom as the camera will give. I get the camera lined up behind the eyepiece first, get the moon on the little screen at back, and then start zooming. Once the camera is zoomed, its field of view is so small that if you lose your target, you may have to start all over again.

Third, I turn off the flash and set the camera to macro (“flower”) mode. I know that other people have gotten good results focusing the camera at infinity, and more power to ’em, but I get my best results in macro mode.

Fourth, it is really super-handy if you have a camera that allows you to manually set the exposure time. My old Nikon Coolpix 4500 does this  easily. If the feature is available on my much newer Coolpix L19, I haven’t found it yet. One of these days I need to rant about how most newer point-and-shoot digital cameras suck compared to the 4500, but not today.

Fifth, take tons of pictures. Seriously. For every photo of mine you see posted here, there are on average 99 others that I took and discarded. I’m not kidding, and I’m not exaggerating. If I come off as a half-decent photographer, it’s because digital cameras allow me to take zillions of pictures and present the handful that worked out. Storage space is effectively free these days, so take as many pictures as you can at the eyepiece and sort ’em out later. It’s worth fiddling with the focus of the binoculars or scope a bit between blocks of photos, just in case the camera’s sweet spot is slightly different from your eyes’ (for example, because you’re farsighted or astigmatic or whatever).

Sixth, download GIMP, which is free, fairly easy to use, and will allow you do just about everything that Photoshop does. Then make a new folder with copies of your best images and start experimenting with Unsharp Mask, Curves, and the rest (do not experiment on your original files).

Seventh, read up on how other people get their shots. What astronomers call ‘afocal projection photography’ is more widely known as ‘digiscoping‘, especially amongst birders, and there are tons of sites out there with advice and examples.

Good luck!


Free logbooks for Lunar II and Messier Clubs now available

January 3, 2010

Over the holiday I made logbooks for the Astronomical League’s Lunar II  and Messier Clubs. No sense in hoarding them for myself. You can download them under “Pages” on the sidebar to the right, or just click this link. I may do one for the Galileo Club as well (Later: I did!). Don’t worry, the downloadable versions don’t have my name on the cover. Happy observing!


Astronomical Resolutions for 2010

January 1, 2010

Looking Back, Looking Forward

Alas, 2009–the International Year of Astronomy–is over. Naturally, a lot of people hope that the activities and institutions of IYA2009 will continue to have a positive impact in the future, but the calendar year is over and the official closing ceremony is fast approaching.

For me, 2009 was a banner year in astronomy. I rediscovered the joys of binocular astronomytwice. I finally, finally got up into the mountains here to take advantage of the darker skies. I got to spend an evening with the 60-inch telescope on Mt. Wilson, which is probably the biggest telescope open to visual use by amateurs. At last I got a decent tripod and mount for my little Mak, which led me to use it a lot more. I used the little scope for 16 sessions of sidewalk astronomy in downtown Claremont, and showed the moon and planets to 916 people. I posted my first article on Cloudy Nights, and started this blog.

So what will 2010 bring? Inspired by good ole Uncle Rod, I have two resolutions for the new year. Like IYA2009, they will hopefully take my observing to the next level during the coming year, and also have longer-lasting effects. One resolution is philosophical, the other practical.

SkyWatcher's 12" Truss-Tube Dob. WANT!

Resolution #1: I resolve to spend less time mooning over the stuff I want, and more time using the stuff I have.

My love of astronomy has always been bound up with a love of telescopes themselves. I like what telescopes represent. I like the fact that a chunk of metal and glass the size of a milk carton can open up the universe. And I just love, love, love scopes as things in themselves. I like looking at them, tinkering with them, and just thinking about them. I don’t think I’ve ever seen an optical telescope, anywhere, ever, without thinking, “I sure would like to play with that.”

The problem is that in the last year–in all of the recent years, in fact–there have been too many evenings when the sky was clear but I was parked on the sofa reading telescope reviews and dreaming about saving up for a light bucket. Just going by time spent, one might get the impression that I like reading about telescopes more than I like using them. Which isn’t true. What got me into this, and what keeps me excited about it, is the almost indescribable feeling of wonder and connectedness that I get when I observe. The moments when I have to get up and walk around just to get hold of myself, when I want to run to the nearest house and pound the door down and drag people to the eyepiece by force, all come when I’m out at night using a scope, not reading about one on the net.

Since I started this blog I’ve been preaching that astronomy is not about hardware and expensive doodads, it’s about getting outside and getting your mind blown. Sure, there are things that I want. But I have everything that I need. So for 2010 to I resolve to get my butt off the couch and observe more.

Now, what to observe?

Globular cluster M2, something I've never seen for myself.

Resolution #2: I resolve to complete the Astronomical League’s Galileo Club, Lunar II Club, and Messier Club.

All too often my observing consists of getting the grab-n-go setup for a quick peek at half a dozen of the best and brightest things. Not that there’s anything wrong with casual observing like that. But I’m getting tired of being a casual observer. I know my way around the sky a lot better than I did a year ago, and I’m better at finding things and getting them in the eyepiece. I’m ready to start challenging myself.

Also, finishing the AL Lunar Club felt fantastic. I want to apply myself to another extended observing program. Doing so will motivate me to get organized, and to start pushing my equipment and my observing skills farther. If I have more of a vested interest in what’s up on any given night, I’ll pay more attention to the geometry and timing of the motion of the sky, and my understanding of the relationship between the Earth and the heavens will deepen.

Why am I choosing these three observing programs? I started the Galileo Club last year and I already laid out a rough schedule for finishing this year. I like the fact that the club requires low magnifications and can be completed with very modest equipment, and I really like the idea of retracing Galileo’s steps.

The Lunar II Club is a natural next step after finishing the Lunar Club. The requirements are quite a bit tougher–instead of just observing a bunch of features and checking them off a list, one must keep more detailed notes and make a written description or sketch of every feature. I’ve never even heard of most of the required targets, and I’m looking forward to hunting them down. Also, if I don’t have something to do on nights when I can’t hunt DSOs, I’ll go nuts.

I’m taking on the Messier Club because it’s just time. In a little over two years of observing I’ve managed to see about 40 of the 110 Messier objects, and I want to see what I’m missing out on with the other two thirds. The challenge of tracking down faint fuzzies ought to motivate me to get up the mountain more often. From here to my favorite observing spot is only about 15 miles, for cryin’ out loud.

With each synodic cycle of moon phases lasting 29.5 days, a calendar year offers 12 windows of opportunity to observe the waxing moon (more conveniently timed than the waning moon), and 12 windows for chasing Messier objects in the darker skies around new moon. The Lunar II and Messier Clubs include 100 and 110 targets, respectively, so I need to average nine or ten targets per monthly window. Each window is several nights long, but I will certainly lose some windows to bad weather, travel, and other demands of life. I think it will be a manageable amount of work, I just gotta get out and do it.

I’ll keep you posted. Happy New Year!