Under Arizona Skies

During a vacation in Tucson, I borrowed an old 10-inch Celestron for some serious recreational skygazing. It has the fairly slow f-ratio of 13.5, which once seemed poorly suited for deep-sky objects but in practice worked very nicely. I had 2-inch eyepieces of 32 and 50mm focal length, giving about 66 and 105x, plus 28mm and 9mm 1.25" eyepieces.

[Digression: I suspect the old prejudice about long f-ratios being bad for diffuse objects arose from thinking that the eye and brain detect light in a simnpler way than they actually do. There are several issues at play, including visual angle of the object, contrast, total brightness, and the brightness distribution so that any bright region may need a certain magnification. CCDs my eyes aren't, but I'm not Borg either, so it's a fair trade.]

This experience got off to a good start when I tried out the telescope from within Tucson, and could find things that are none to easy from home with my 10-inch Coulter Odyssey. M105 (NGC 3379) and its companion NGC 3384 popped up easily, along with comet Ikeya-Zhang. The comet was bright enough in early June 2002, but quite diffuse with no particular nucleus or tail. Stars were resolved in M3 and M13, and the view of M57 was pretty crisp at 350x or so, which boded well for chasing out to darker sites.

My next try was on the west side of the Tucson Mountains, so that at least that half of the sky was pretty dark. M13 showed a sea of red giants, and M104 was nicely split by the dust lane. In the Virgo Cluster, I could waltz up Markarian's Chain. I picked up the globular cluster M62, a new one for me, showing up small, with high surface brightness, and slightly resolved into its brightest stars.

Telescope setup at Las Cienagas What I had been especially looking forward to was heading down to the Las Cienagas (formerly Empire Ranch) site with the Tucson Amateur Astronomy Association for their June 8 outing. Getting there was part of the fun, since the only car the rental agency had left when we arrived was an SUV. The pictures show my vacation gear set up, including the very important 44-ounce Pepsi. The site is nearly an hour from Tucson, and most of the sky s nicely dark from there (I did get a nice instructive photo of the city's light dome). Finding deep-sky objects really was too easy from such a dark site (even without using setting circles or fancier techniques); I did find that starting with an all-sky chart like the DeepMap helped get oriented in areas of the sky that I didn't already know pretty well. About an hour into twilight I could see not just M65 and M66, but the fainter third member NGC 3628 of the Leo Triplet. Thus emboldened, I looked for a particularly interesting target that was dropping into the twilight, the galaxy cluster Abell 1060 in Hydra. It's easy enough to find from Corvus, what with that annoying fifth-magnitude star in front of the cluster. Aha! The double ellipticals NGC 3309/11 showed up in the center, joined quickly by the giant spiral NGC 3312, other members NGC 3308/16, and my particular favorite the silhouetted spiral pair NGC 3314. I always get such a kick out of looking with my own eyes at objects I've worked on more seriously.

Light pollution
from Tucson beneath Ursa MajorFor the first part of the night, I intermingled new objects (such as the 16 Messier objects I hadn't yet looked at) with old favorites seen in a new light. M104, the Sombrero, showed not just its familiar dark grin, but the dust lane stretching well out into the disk. Something that didn't show up from closer to Tucson was the enormous extent of the galaxy's central bulge, wrapping outside the visible flat disk. M83 was an obvious fuzzy patch in the 6x30 finder - hmm, things I'm used to hunting for in the 10-inch at home are finder objects out here. Its bar and disk showed up clearly, along with the slightly lumpy condensation of the starburst nucleus. While in the neighborhood, I had a look at NGC 5128 = Centaurus A. Another one for the finder. The two bright lobes on either side of the dust lane were obvious, and I could just make out structure in the absorbing features south of the main lane (near the bright foreground star). Dropping five degrees to the south, I found that the telescope hit the fork supports with Omega Centauri at the edge of the finder field. Off to hunt some rocks for those tripod legs...

Still no interesting structure in Comet Ikeya-Zhang, so I headed back to the outskirts of the Virgo Cluster. NGC 4192 was long and thin, but I couldn't make out the dust lane. NGC 4321=M100 showed a distinct nucleus (the inner spiral pattern, the one that wowed everybody in the first released HST image after refurbishment) and a very large disk. I did notice the elongated galaxy about 15 arcminutes to the SSW, which would be NGC 4312. I then took a quick look at M85 (NGC 4382) and its spiral buddy NGC 4394, and then decided it was time for a little spectacle.

M51 was a bit of a surprise. It is, naturally, the poster child for seeing spiral arms, and I've had great views with a 50-inch telescope (plus one cool night with the Kitt Peak 2.1-m and an image tube, after another instrument broke down). This was another finder fuzzy under dark skies. Through the 10-inch, it showed a beautiful pearly disk, and the visual impression was that the spiral pattern consisted of the dark dust features twisting within it. Given some of my research interests, it's funny that I would see it this way. The companion NGC 5195 shows an especially sharp and bright nucleus. To add to the treat, a satellite went through the field at about 2145 MST (must have been pretty high, even in the summer, to show up that late).

Continuing with showpieces, I tried M101. This has been a real problem for me from Alabama (coming clean, I've never found it with my 10-inch Dob). Once again, a big fluffy thing in the finder. The inner regions gave the impression of a twisted starfish, although I couldn't actually trace a continuous spiral pattern. A couple of the giant H II regions to the E and WSW showed up, probably NGC 5447 and 5461. (Hey, I got data on 5461 with FUSE. Small universe.)

While in the neighborhood, I bagged "M40" just for completeness. Heading farther south, M3 was nothing short of magnificent. Hundreds of red giants peppering the smooth background of fainter stars, which spanned the whole field. This reminded me of one of the shots near the end of 2001: A Space Odyssey. A brief detour back to Virgo, to pick up M49 (I recognized it by the bright star next door). Time for more eye candy, so I went to NGC 4565. Its visible disk spanned 2/3 of the 32mm field, with the dust lane clearly splitting it from end to end. This is much more of the galaxy than I recall seeing before, a place that the dark skies really make a difference. By now the Milky Way was rising in earnest, so I could do the trick on myself suggested by several people (I may have gotten it from Adam Block at Kitt Peak) of staring through the eyepiece at one edge-on spiral, then backing away, turning around, and looking at another one.

Next stop, the core of the Virgo cluster, so I can finally get all those bright galaxies straight. They were close enough together that I started at M87 and used the slow motion knobs to move around while at the eyepiece. M87 is big, round, and bright, with identification verified by its little buddy NGC 4486A just off to the southeast (looking back, I suspect NGC 4486B masqueraded as a star on casual inspection). Next, M58=NGC 4579. I was pretty sure the bar in this spiral showed up. M90 = NGC 4569 was big, elongated, and sported its famous starlike nucleus (which turns out to be about 0.1 arcsecond across and full of A-type supergiants, but that's a different story). M88 (NGC 4501) was likewise big and bright, not quite as elongated, and showed a fairly bright nucleus. A pair of stars just to the south helps identify this one at the eyepiece. Moving to the southeast, a single field showed M60 and its companion NGC 4647, M59, and NGC 4638. Looking back at the map, I then found that I had already picked up M89 in zigzagging back and forth between these other galaxies. My last new galaxy in Virgo was M61=NGC 4303, showing a semistellar nucleus. The disk showed mottling, but not clear enough for me to discern a spiral pattern.

Back to the north, for a little more neck stretching with the tight clearances of the C-10 fork mount. M102=NGC 5866 showed up as a neat little lozenge of high surface brightness, although I couldn't pick out the narrow dust lane. Next door, NGC 5907 was a thin streak extending halfway across the 32mm field of view, with a litle bulge in the middle.

Two more globulars finished my Messier list. M68 has pretty low surface brightness for a globular, and lacks a distinct bright core, but did offer lots of resolved stars. M107 was pretty similar, with fewer individual stars showing up. So, at 2310 MST, I finally cleaned up the gaps in my Messier list.

Now it was pure sightseeing. M22 was simply glorious, my favorite summer showpiece for the two hours or so that it's high enough to get a good view. Folliwing the Scorpion's tail around into Sagittarius, I had a look at the blazing stardust of NGC 6231, and the brilliant (but really too big) members of M6 and M7. The Lagoon (M8) was huge, with the nebulosity clear on both sides of the "lagoon" dust feature. The Trifid (M20) showed both the emission and reflection pieces of the nebula. On a later night, I asked Nathan (age 9) how many dark stripes he saw, just to be sure I wasn't fooling myself about seeing the whle set of lanes familiar from pictures. The Omega or Swan Nebula (M17) is probably the best summer nebula, and showed big and bright. New to me were some of the outer loops, separate from the main part of the nebula. The Eagle Nebula (M16) showed only ill-defined nebulosity, most apparent between two clumpings of stars. And the Wild Duck cluster (M11) was epic. It gave the impression of a rhomboidal window, complete with four panes, and a single bright candle in one of them.

I brought several charts to hunt Pluto, now in a pretty easy-to-find place in Ophiuchus. After about 20 minutes, I was pretty sure it was visible with averted vision, and made a sketch. Pretty dim for a 10-inch...

Everybody's stargazing was interrupted by a nice landscape-illuminating fireball at 0027 MST. Many vocalizations of various kinds rang out, but nobody seems to have had a shutter open. And I was only 2 feet from the cable release.

I enjoyed prowling around in Baade's Window, as close to the galactic center as an optical view can penetrate. The Milky Way showed extraordinary texture, as the view was chopped up by dust patches at various distances from us. The two globular clusters NGC 6522/8 southwest of Gamma Sagittarii were an interesting comparison, with similar angular size but different surface brightness (dust absorption likely does much of that).

A few more globulars, all over the sky. M13 was a blaze of stars right to the center. I fished around and found the galaxy NGC 6207 as well. M4 was its usual well-resolved self. I even blundered across M56, quite by accident (well, if it worked for Messier...)

As I was refreshing the palate with M57 and Albireo, we could feel hot and cold running winds - alternating from different directions, with temperature a good 10 degrees F apart. The seeing deteriorated at this point, but there was stil lots to see. The ends of the Dumbbell, M27, were closed in this view, giving it a different appearance than I'm used to. And I always heard that the Veil Nebula was hard (which is accurate, from Alabama). NGC 6960 first looked like a reflection from 52 Cygni. No filter or anything, but there were hints of the multiple filaments in this part of the loop. It showed up best in the 50mm eyepiece, the widest field I had.

Finishing up the night, it was back to galaxy-land on the other side of the Milky Way. NGC 7331 gave its familiar impression of a baby Andromeda, though both were much larger than usual. I didn't manage to find Stephan's Quintet, maybe not surprising since I didn't bring a very detailed map for them.

Jupiter and
Moon in conjunction To top off the dark-sky gazing, I took the telescope up adjacent to a nearby observatory, having verified that some old friends were observing there and wouldn't mind my setting up in the parking lot. On top of the usual suspects, we had a look at a few additional galaxies. M64 showed the thick dust patch clearly, and not as dark as some pictures would have you believe. This shows the difference between any simple stretch of a linear image (linear, logarithmic, whatever) and the eye's perception. M94 is always very bright, and from here it was also extremely huge. The inner disk showed some texture if not quite the tight spiral pattern, and (a first for me) the outer disk showed up, stretching about three times the extent I was used to seeing. We were fighting wind on this evening, but did get some OK scenic pictures of the Moon near coinjunction with Jupiter.

In summary, if the three main considerations in real estate are location, location, and location, the three main issues in seeing objects in the deep sky are dark skies, dark skies, and dark skies.

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Last changes: June 2002