Observing Report: SkyScanning in OregonOctober 2, 2012
I was up in Oregon last week to visit my university’s second campus in Lebanon. It was a kill-many-birds-with-one-stone type trip: in addition to day-job work in Lebanon on the weekdays, I got in a productive meeting about a joint project with a paleontological colleague who lives nearby, and–the point of this post–last Wednesday night I got to go stargazing with frequent commenter Doug Rennie.
Doug lives up by Portland and I was staying in Albany, so we needed someplace in between with reasonably dark skies. We settled on Baskett Slough Wildlife Refuge, just north of Dallas, OR. We met in Dallas for dinner and then drove out to the slough.
I had along a new-ish pair of Nikon Action 10×50 binoculars that I picked up this summer and haven’t used much. Doug brought his Celestron SkyMaster 15x70s–the same model I have and love–and his Orion SkyScanner 100 tabletop telescope.
Neither of us really knew what to expect in terms of sky quality. The waxing gibbous moon was only three days shy of full, and I was seriously concerned that we’d get “mooned out” and not be able to observe anything in the deep sky.
This brings up the interesting question of how much moonlight it takes to significantly degrade the night sky. I’ll write a full post about it someday, but for now it is enough to note that the brightness of the moon increases exponentially on the run up to opposition (full moon), and decreases exponentially after full moon. For explanations of why that is, check out this graph and this tutorial and read up on opposition surge and heiligenschein. The upshot is that three days shy of full the moon is only perhaps a quarter as bright as it is at full moon, and happily we were able to see quite a bit.
I didn’t know that when we started out, though, but I knew that we wouldn’t see anything if we didn’t try. Ursa Major was opposite the moon, getting closer to the horizon, and with it some of the best and brightest galaxies in the sky. I spent a few minutes faffing around and managed to get M81 in the field of view. It was dim, but it was there, and our observing run was underway.
Some hazy clouds were skirting the northern horizon, and I was worried they might come south and ruin things for us. Also, after the frustrating chase and unimpressive view of M81 we needed a win, so our next target was the Double Cluster, NGC 869 and 884. They were spectacular–two brilliant knots of stars in the rich Milky Way starfields of northern Perseus.
After that we hit some other summer and fall “best of” objects, including the Andromeda galaxy (M31), the Great Glob in Hercules (M13), the Ring Nebula (M57), and the Dumbbell Nebula (M27). Next to M31 we caught the brighter and more compact of its two Messier satellite galaxies, M32. I don’t know if M110 would have been visible or not. It’s a tougher catch, especially under less-than-perfect skies, and I didn’t waste any time looking for it.
M13 was an easy catch, and we kept running up the magnification to see if we could get it to resolve at all. Doug’s 6mm Expanse yielded 67x and, we thought, some tantalizing hints of detail. We Barlowed it up to 133x and the cluster took on the slightly grainy texture that is often the most resolution one can get in a small scope. We also tried lots of magnifications on the two planetary nebula, M57 and M27. We could only glimpse in averted vision the slightly darker center that makes the Ring a ring, and the Dumbbell showed the barest hint of its bilobed structure.
After that we turned back north and plied the starry Milky Way between Cassiopeia and Perseus. Cassiopeia is just lousy with asterisms and open clusters; the only ones we bothered to identify were M103 and nearby NGC 663, which is bigger and brighter.
A highlight of the evening was sweeping the Alpha Persei Association with binoculars. It’s really seen best this way–very few telescopes have a wide enough field of view to show more than a small part of it. I once read a description of this big, close cluster–variously catalogued as Melotte 20 and Collinder 39–as a “vast wonderland of far-flung suns”, and I can’t look at it without those words coming to mind.
Since Perseus was now a good way up the sky I thought it would be worthwhile to track down the open cluster M34. I’m glad we did. When Doug looked at it he said, “I know this cluster–I’ve drawn it!” And he had–his sketchbook recorded the fingerprint-specific arrangement of stars that make up the cluster. I was most impressed by this–by the drawing and his visual memory both.
At this point we were winding down a bit and just scanning around with binos, taking things as they came. Halfway down the western sky I found the brilliant blue-white double star 16/17 Draconis. By this point Doug’s green laser pointer was fading a bit from cold and overuse, but with some yammering and gesticulating on my part–and much patience and good humor on his–we were able to get both pair of binos on target. That really is a gorgeous double, and just wide enough to be clearly split in low-power binoculars. I recommend it.
Our last stop of the night was the Pleiades, which had just climbed over the northeastern horizon. They were stunning, as always. That gave us a total of nine Messier objects, three non-Messier NGCs (663, 869, and 884), another big open cluster (the Alpha Persei Cluster), and a double star. So, 14 objects in all, which is pretty good for a two-hour session under any conditions.
Using the SkyScanner was a revelation. I had taken a few brief peeks through Terry Nakazono’s SkyScanner on our Baldy runs, and been impressed, but I’d never gotten to just pick one up and freewheel. And “freewheel” is a pretty good description of what we were doing. The scope is light enough that you don’t think twice about just picking up one-handed and moving it wherever you need it. At the same time, four inches is a lot of aperture, and I was consistently impressed by how much the little scope could do, both in terms of light-grasp and resolution. Doug must have collimated it to within an inch of its life, because the image was still good at 133x–a real achievement in any small, fast Newtonian. Finally, I didn’t notice any issues with the focuser. This is one of my pet peeves. Fast scopes have steep light cones and it takes a precise focuser to consistently hit focus without going past in either direction. One of the things that drove me crazy about the Celestron FirstScope was the lousy focuser, which consistently overshot focus. So when I say the focuser on the SkyScanner didn’t draw attention to itself, that’s a good thing. I’m sure that like all consumer scopes there’s some sample-to-sample variation with the SkyScanner, and Doug’s might be an unusually fine example, but so far both of the SkyScanners I’ve gotten to use have impressed me. I think I’ll get one for the Suburban Messier Project, which is on hold until it cools off some–it was 107 here today. In October!
Oh, and speaking of the Suburban Messier Project, I was most impressed by the quality of Doug’s sketches, and by the fact that, having sketched something once, he could recognize it at the eyepiece later without knowing in advance what it was. I’d like to have that level of familiarity with these objects, and I intend to get it–by sketching them. Stay tuned.