Archive for the ‘refractoritis’ Category


Unboxing the Bresser Messier AR102S Comet Edition

January 31, 2017


I’ve been interested in this scope since late 2014. The Celestron TravelScope 70 turned me on to the joys of refractors back in 2012, which led to the C102, which led to the C80ED, which got me firmly hooked on low-power, widefield scanning, which led to this.

This is the Bresser Messier AR102S Comet Edition, which I believe is a record for the longest name of any telescope I’ve owned. And you actually do need all of it, because there is another Bresser Messier AR102S that is a completely different scope. That other AR102S is a standard f/6 achromat. The AR102S Comet Edition is an f/4.5 rich-field scope. And as you can see from the photo, it’s built funny. Instead of having the focuser at the back end of the tube, the focuser is mounted on the side of the tube, as in a reflector, and a reflector-style secondary mirror* bounces the light from the objective lens to the eyepiece. This makes for a very short, compact scope, and theoretically for easy collimation via that secondary mirror (I haven’t tried that yet). Scopes like this are sometimes called “reflactors” because they combine an objective lens with a secondary mirror. I’ve seen ATM builds using this design, but I’ve never seen another one marketed commercially.

* Existential telescope question: is it still a secondary mirror if there’s no primary?


As far as I know, this scope has only ever been sold as part of a travel kit that includes the OTA, an eyepiece, an alt-az mount, 7×50 binoculars, and a backpack to carry it all. That package has a list price of $349, but the list price has been creeping downward. Explore Scientific’s online store and both carry the AR102S Comet Edition (man does this scope need a nickname) package for $299, but B&H Photo-Video has it for $249 with free shipping. Amazon used to have it for $249 as well, but I seem to have gotten the last of those – as of this writing, the price is hovering in the $340s.

I’ll have a first light report along soon, this one is mostly photos of the unboxing and the scope.


Outer box…


…contains the middle box…


…contains the inner box. That’s right, three boxes before you get to anything other than packing material and the instructions.


Inside box number three are the backpack and two more boxes.


Inside the backpack is the OTA in a plastic bag, and on the right you can see the eyepiece peeking out of the side pocket.


Oh, also in the backpack are the 7×50 binos. Everything bagged.


And inside the bags, the telescope OTA with wrapping paper, the binocular case with the binos in yet another plastic bag inside that, and the eyepiece bolt case with the eyepiece in yet another plastic bag inside that. Oh, and a couple of hex wrenches inside the bag with the bolt case, for collimating the OTA.


And here’s everything finally outside of the various bags, bolts, and cases.


The OTA is 20″ long and 4″ in diameter, with a 4 1/4″ diameter dew shield. In the shots before this one, you can see the dovetail on the right side of the OTA, and here you can see the shoe for a finder (not included) on the left side of the OTA. Having the dovetail on one side and the finder shoe on the other is convenient, because it means the OTA can’t roll over and bang the focuser if you set it down on a flat surface.


Here’s the lens cap. If you’re thinking it looks like a Meade, you’re not wrong.


And way down inside the dewshield, 4 1/4″ in, is the objective lens, with its dark green anti-reflection coatings. The achromatic doublet is fully multicoated. The dewshield has an outside diameter of 4 1/4″, and an inside diameter of 4 1/8″. Past the objective lens you can also see the single baffle inside the OTA, which is otherwise just painted flat black inside.


Remember those other two boxes? The long one has the tripod and the short one has the alt-az head.


The alt-az head, which is metal, and the eyepiece tray, which is plastic.


The mount assembled. The alt-az head looks like my SkyWatcher AZ-4/Orion VersaGo II, but it lacks the adjustable tension knobs.


Here’s a feature that I really like: the eyepiece tray goes solidly onto the spreader bars with no tools. It threads over a central bolt, and then rotates to snap into position. This is super-handy at the end of the night, because I can unlock and rotate the eyepiece tray without taking it off, and fold the tripod legs in just enough to get through the door.


The whole rig set up. The tube looks not quite square here, but that’s just field distortion from the iPhone camera, which we’ve seen before here.

The OTA weighs 6.2 lbs, the mount weighs 6.8, so the whole rig clocks in at 13 lbs even. That’s pretty portable, although certainly at least flirting with being undermounted. More on that in the first light report.


User end. The eyepiece is a Bresser 20mm 70-degree model, which is currently on sale for $40, down from $60, at If you’re thinking that $60 seems like not much money for a new fully-multicoated 70-degree eyepiece, I agree, and I am likewise suspicious. I assume it’s some kind of Erfle, but I haven’t taken it apart to confirm. The size, form factor, and even barrel detailing are very similar to Orion Sirius Plossls, but the eye lens is just slightly too big for Sirius dust caps to fit (which is a shame, since it gets in the way of me stuffing this thing in my pocket while I swap Plossls and Expanses around). It gives 23x and a 3-degree true field of view.


Here’s the left side of the back end, showing the finder shoe, the collimation bolts for the secondary, and another look at the focuser. The focuser is an all-metal rack-and-pinion job. Oddly enough, the focuser drawtube is 2″ in diameter but the 1.25″ adapter at the top is permanently mounted. So it’s a 2″ focuser that only accepts 1.25″ eyepieces. I think there’s a reason for this – the focal plane is 6-7 inches (150-175 mm) away from the center of the OTA, which means at least a third of the 459-mm light path occurs after the light hits the secondary. I think a 1.25″ drawtube would cut into the light path and stop down the scope.

The finder shoe is not one I’m familiar with. Almost all of my experience is with gear made by Synta (Orion/Celestron/SkyWatcher), which uses the same mostly-but-not-quite industry standard dovetail shoe for finders. This is a weird square rig that is outside my experience. I probably won’t use a magnifying finder – I can get by okay just dead-reckoning, and when I feel like cheating I can lay a laser pointer along the dovetail shoe or the square edge of the focuser and get on target very fast. But I might put a counterweight there, to get the balance point a little farther back so the eyepiece height would change less going from horizon to zenith. Or here’s an interesting thought: I bet I could gin up an eyepiece rack that would attach to the finder shoe. That would be cool, convenient, and a counterweight.

Here’s the focuser again, with the axis drawn in blue. This is to make a point. I’ve seen one or two folks on Cloudy Nights alleging that this is a “leftover scope” – that Bresser/Explore Scientific had some leftover tubes, leftover secondaries, and leftover focusers, so they cobbled it all together into this Frankenscope. But that doesn’t hold up. The focuser is a single-piece aluminum casting with two features of note. First, it wraps tight to the 4″ diameter tube, which if it was leftover from a reflector would have housed a smaller-than-4″ mirror. There are 3″ reflectors out there, like Orion’s SpaceProbe 3, but no-one puts 2″ focusers on them. Second, and more importantly, the focuser knobs point across the tube on this scope – that’s what the blue line shows in the image above – as opposed to down the length of the tube as in all mass-produced reflectors. Again, the focuser is a single chunk of aluminum – the 2″ tube can’t be separated from the base, or rotated relative to it. So I’m confident that this focuser was purpose-built for this scope.

The “leftover scope” idea was pretty dumb anyway. The most expensive part of any refractor is the objective lens, which has to be figured to a tolerance of a millionth of an inch. The rest is just steel, aluminum, plastic, and fasteners, which cost peanuts by comparison. As far as I’ve been able to tell, neither Bresser/Explore Scientific nor their parent/partner Jinghua ever sold a 4″ f/4.5 scope before. It doesn’t make any sense to figure a bunch of bespoke objectives – the expensive part, especially after full multi-coating – just to sell the cheap hardware.

So, somebody decided that a fast, 4″ reflactor was a good idea. Were they right? Tune in next time and find out.


Observing report: Deep and dark in Big Bear

October 12, 2015

Big Bear Lake

This past weekend I was up in Big Bear for a few days’ vacation. The proximate reason was the PVAA tour of the Big Bear Solar Observatory on Friday, Oct. 9 – more on that in another post. London and I went up Thursday evening with Steve Sittig, who runs the Hefner Observatory at the Webb Schools here in Claremont. Thursday evening Steve took us out to one of his favorite dark-sky observing sites a few miles east of Big Bear. (I didn’t get any pictures from the observing site, so you’re getting pictures of London and me hiking instead.)

We had hoped to get an early start but a succession of minor things kept us from getting set up and going until about 10:15 PM. By that time astronomical twilight was long over. There was a noticeable light dome from the LA metro area but it only badly affected the last 15-20 degrees above the local horizon, and only in the southwest.

Oh, speaking of the ‘local horizon’ – the site is in a shallow bowl with low hills fairly close on three sides and a bit more distant on the fourth. We could occasionally see lights from vehicles on a bend in the road about a mile off, but other than that, no artificial lights were visible from the site. None. The altitude is around 6700 feet.

The combined effect of this was that the sky was dark right down to the horizon. There was none of the usual near-horizon crud that obscures objects for the first 10 or so degrees after they rise. The seeing was worse near the horizon but the transparency was still excellent. We looked at Orion virtually as soon as it was up, and although we really had to pour on the magnification to split the Trapezium, the nebulosity was already very extensive.

A word about gear. Steve had his ETX 125, a 5-inch f/15 Mak on a motorized base with a hand controller. London had his Orion 20×50 compact spotting scope – I have been regularly kicking myself for not snapping up one of those for myself while they were still available. I had my C80ED refractor on the SkyWatcher AZ4 mount (= Orion VersaGo II), as well as my trusty old Celestron UpClose 10×50 binos. The choice of the C80ED was driven by two things: my space on the drive up was limited, so it was either the C80ED or the Apex 127 (which would have basically duplicated Steve’s rig), and I knew I’d want to do some wide field, low power observing, which is the one thing the Apex 127 can’t do.

For eyepieces, I spent most of the night using the 24mm ES68, which in the C80ED gives 25x and a sprawling 2.7-degree field. When I needed more power – which is much less often than I had anticipated – I bumped up to the 14mm and 8.8mm ES82s (43x, 1.9-degree field, and 68x, 1.2-degree field), and on a couple of tough double stars, the 6mm Expanse and 2x Shorty barlow. Unusually for me, I didn’t even mount a finder. With a 2.7-degree field, I can usually get the scope on target just by sighting down the tube. On those occasions when I needed more accuracy, I could lay my green laser pointer into a couple of shallow v-shaped notches on the tube ring and just move the scope until the laser was pointing where I wanted to go.

London Big Bear hike

Within moments of hopping out of the car, we could see loads of detail in the Milky Way with our naked eyes. The Double Cluster and the Andromeda Galaxy were both easy as well. Later on, we also spotted the excellent open clusters M35 and NGC 752 without optical aid. I logged the seeing as 4/5 and transparency as 5/5.

Our first few observations were “best in class” objects – the Pleiades, the Double Cluster and Stock 2. At low magnification under dark skies, the Double Cluster looks not so much like a pair of isolated objects, but rather a couple of thickenings or condensations in an incredibly rich Milky Way starfield. So it was that evening. Seeing that far above the horizon was rock steady and even at low mag, the C80 focused the stars down to tiny pinpoints of brilliant light. One of the clusters has a pair of red giants near its center – these were visibly brighter and more yellow than the rest of the cluster stars, even at 25x.

After that I turned west to catch M13 before it got too low. Going up to 68x revealed tantalizing hints of resolution – not bad for an 80mm scope.

M57, the Ring Nebula, was an arresting sight. At 25x, I could get both of the ‘corner’ stars that mark that end of the Lyra parallelogram, with M57 as a small but crisp circle of nebulosity floating in inky dark space. Although we also looked at the nebula with more magnification, I found that lowest-power view delightful. It reminded me of spotting the Ring at 12.5x in the TravelScope 70 three years ago – the view that first infected me with refractoritis.

We didn’t try to split Epsilon Lyrae until a bit later, when it was lower in the sky. The seeing there was only so-so and I had to push the scope to 200x, using the barlowed 6mm Expanse, to get a clean split, although both pairs were visible elongated at much lower magnification.

We stayed out long enough to catch the leading edge of the Big Dipper rising. One of the best views in that part of the sky is the galaxies M81 and M82 in the same field of view. They are close enough to be nicely framed in the same field even in the 8.8mm ES82. At that magnification (68x), M82 was starting to show tantalizing hints of structure.

London and Matt hiking above Big Bear Lake

The most memorable observations of the night were of the Auriga Messier clusters and the other Local Group spiral galaxies. Auriga clusters first – M38, M36, and M37 (from west to east, in the order that they rise) are seasonal favorites and fun to compare. We swept them up easily in binoculars and then scrutinized them in the scopes at progressively higher powers. I had a good laugh at M36 – at the orientation we saw it in this weekend, it looked like a short, fat stick figure, the bobble-head version of the Stock 2 stick-man. But M37 was my favorite, just an incredibly dense swarm of tiny pinpoint stars.

Fairly early in the evening we had a look at the Triangulum galaxy, M33. I was tracing out the constellation Triangulum with the GLP when we noticed a naked-eye glow that turned out to be the fine open cluster NGC 752. Neither of us could make out M33 with our naked eyes but it was dead easy in binoculars, and at 25x in the C80ED it showed considerable structure in averted vision, including what both of us independently took to be one of the spiral arms. Incredible.

We closed the session with another great view of a local galaxy. All through the three-hour session we’d been saying that we’d look at Andromeda, and then one thing or another would capture our attention and we’d get sucked into some other part of the sky. We finally got around to M31 and its companion galaxies a little after 1:00 AM. By that point they were basically at the zenith. Even with the tripod extended as high as it would go, we had to kneel to look in the eyepiece. But when we did, the view was astounding. M31 stretched all the way across the field, with only the very outer edges clipped by the eyepiece’s field stop. The little companion galaxies M32 and M110 were dead easy, of course, but what amazed me was that we could both see structure and detail with the main galaxy. I’d never seen those dust lanes in anything smaller than a 5-inch scope.

We knocked off after three solid hours of observing, exhausted but giddy. It was one of those transcendent nights that makes my heart sing, and also makes it really hard to go back to observing from suburbia. The most surprising thing for me was how much observing I got done with the 24mm ES68. “Small telescope at low power” does not scream satisfying deep sky observing, but under sufficiently dark, clear skies, I rarely needed anything else. I’m already looking forward to the next run.


Observing Report: Night of the Refractors redux

November 20, 2013

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).


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.


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.


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.


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 ( 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.


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.


Ken Fulton on refractors

October 24, 2013

If I’m succumbing to refractoritis, I’ve at least had some help getting there. David DeLano and Terry Nakazono have let me look through their big beautiful lens-based scopes. Darrell Spencer posted about the crisp views through his huge refractors on CN. And Doug Rennie sent me this back in August. It’s an excerpt from Ken Fulton’s under-appreciated book, The Light-Hearted Astronomer.

Read it at your peril.

Ken Fulton - Light Hearted Astronomer - excerpt on refractors