My Observing Log: November/December 2001

11:00 p.m. 2 November 2001 PST (2001–11–03–0700 UTC)

Beautiful night, waiting for me. When I looked out the window after putting my son to bed, I saw Saturn and a nearly full gibbous Moon, halfway up the eastern sky. And I saw haze. The haze didn't bother me, since with the bright Moon up, I didn't plan on doing too much DSO hunting. In fact, if anything, it presaged good seeing.

With everything else done, I set up at about 11, the first time I had had Opus out for a serious observing run in some time. I've been playing around with the 10-inch Starsplitter, not really pushing it hard at all, and it was nice and comfortable to head back over to this 5-inch SCT. It's still my planetary scope of choice, until I get some aids to consistently get the collimation on the Starsplitter as good as I can get it on ol' Opus. (Yup, the Starsplitter has no name. I'm still working on that…)

No need to draw up an observing list—I had just a couple of targets that I wanted to see, and they were easy to find. Saturn was higher and first. Even within the first five minutes, I could tell this would be a good night; the globe and rings looked blurry, but there would be flashes of steadiness where everything crystallized. These were the "breaks" in tube currents, and would go away as soon as I and the scope had equalized. (And I do mean "globe." "Disc" wouldn't do justice to the depth I could see already.)

While I waited, I headed down to Jupiter, then getting reasonably high (about 25 degrees in altitude) in the east. A decent view, even here, and I noticed, as I was centering the planet in the finder, that only a couple of the satellites could be seen. Some sort of event was taking place, I could only assume. I popped open my Palm and checked it out. Sure enough, Io and Europa were headed for a dual transit and shadow crossing. It was while I was checking for the shadows that Jupiter seemed to magically steady, and both shadows stood out in reasonable clarity. (I've seen better, but it was pretty darned good, for being so low in the sky.) I tried to make out Io, then already on the disc of Jupiter, but no dice.

Back to Saturn, where the view was now almost frozen—just about as good as I've ever seen the ringed planet. The C or crepe ring was dim but definitely there. The B ring started out bright near the Cassini division, then held that brightness for about half its width, then began dimming toward the inside edge, and then, just at the edge, dropped precipitously to the filmy dark nothingness of the crepe. Outstanding! Speaking of Cassini, it was visible all the way around, and the Encke minimum was practically easy, showing across about half the A ring—a quarter for each ansa.

The globe of Saturn was something else, too, with its leading edge just a tad darker and contrasting sharply with the ring at its southern extremity. On the trailing edge, the sunlit limb was noticeably brighter, and the contrast accordingly lower. Very neat effect. Also neat to see the globe of Saturn just dipping into the Cassini division, with the A ring showing all the way outside. Quite noticeably darker temperate zone in the southern hemisphere, with a paler equator, and even a pair of festoon-like projections from the temperate zone into the equatorial zone on the trailing side of the planet. The polar region was brighter than either.

Then back to Jupiter again, now higher in the sky and showing still more detail. There were festoons here, too, but I was struck by how faint they seemed, in contrast to the last apparition. Also, the NTB had a much more subdued color than before. I've seen it in the past with a vivid orange, more orange than the NEB. This time, it was just a bland grey-brown. The NEB itself was still orange, but not outstandingly so, with the festoons a very pale steel blue. The SEB was grey-brown, too, and broken up. One of the shadows (Europa's?) was just trailing the GRS off the leading edge of the disc, and the other shadow was, I think, just trailing a small oval. But I couldn't be sure about the oval; it was at the limit of visibility, if I wasn't making it up.

Toward the end of the session, the areas further south were beginning to take shape. There was an apparent peak just a little behind the central meridian. I could tell there was texture there, but couldn't quite make it out. Something similar was happening in the far north, too. I was losing steam, though, and I cut it short before I lost motivation to tear down properly, too.

Very nice night and return to active duty for good ol' Opus!

A few more details from this observation session. All the observations were done with the 6 mm Tele Vue Radian for 208x nominal magnification, except as noted below.

I also observed Plato, on the Moon, following up my own letter in a recent issue of Sky and Telescope. For whatever reason, I was only able to make out the big four with any certainty. The others were either invisible, or lost near the edge of Plato.

I used a 15 mm TV Plossl for 83x nominal magnification on the Trapezium, and could not make out either E or F. I suspect in this case it was because I was already beginning to dew a little, combined with the nearby gibbous Moon. (Should have put on that dew cap!)

It was so steady that I briefly tried the 2.5x Powermate in conjunction with the Radian, for 520x. Amazingly, the image only broke down a little bit, but it certainly was easier to see detail at 208x, so I took it back down. (The higher power did make it somewhat easier to see a third Saturnian satellite, which I haven't yet gone to check its identity.) I made a try for some spokes—the seeing really was that good—but the B ring seemed pretty smooth to me, with no detectible striations.

11:00 p.m. 7 November 2001 PST (2001–11–08–0700 UTC)

Looked like another decent night of seeing, so I set up Opus again, my telescope of choice for higher-power observations. That happened around 10:00 p.m., while I was still cleaning up the house and all. In the meantime, I had the Wocket out (the 70 mm Ranger) and checked the field for Vesta. Took a couple of moments, as PleiadAtlas was showing me a field of stars dimmer than I could see through the scope, but after a minute or so, I found it. Easy to see—the only issue is identification. There were a trio of seventh-magnitude stars, with Vesta next to one of them. A quick check of the interior angles revealed that Vesta was interior—just as shown on the Sky and Tel map. (PleiadAtlas doesn't map the asteroid itself yet.)

Then, at 11:00, I came out again, and made a disheartening discovery. I had forgotten to put the dew cap on, and there was now a thin film of dew covering Opus's corrector plate. Now, what to do? It was too late to run a blow-dryer out in the backyard, and I had the whole scope set up—I didn't want to have to drag it back in to dry up.

It looked silly, but in the end, I decided for emulating a Kendrick system. I wrapped my hands around the outside of the OTA, where the corrector plate is supported, and waited for about ten minutes. I also covered up the scope with a dry, lint-free cloth, and let my chest radiate heat into it. It worked! (Well, it's pretty mild in southern California.) Corrector plate dry, no problem.

Despite the appearance of the sky, the seeing was not as good as it was on my previous time out. Still good, though. I made a positive identification of the Encke minimum, and I think I saw the crepe ring, too. The equatorial dark feature I saw the last time was not there, but I haven't figured out whether it should have been.

I also looked southward a bit for Vesta. This time, despite the reduced true field of view, it was much easier, with the field stars matching that on my Palm almost exactly. The EQ mount, making it quicker to identify north in the eyepiece, also helped. I could tell that it had moved, just perceptibly, in the hour or two—the angle from two of the seventh-magnitude stars, meeting at Vesta, had changed.

Then down to the Trapezium. This is one of those fields that I use the 15 mm Plossl on, since it was with that eyepiece that I first saw E and F together. I don't know why, but that magnification just makes it easier for me. I saw E tonight, but not sure about F. There were a couple of times that I thought I had it, but I wasn't certain. I mean, I know where it is—it's easy to fool yourself.

Last up was Jupiter. It was lower, and the degradation in the seeing from this night to the previous one was most obvious here. The NTB, NEB, and SEB were distinct, with the SEB showing a bit more color. There were hints of the EB, but only in the trailing half of the disc. The GRS was barely visible on the leading edge; I could see no detail in it, whatsoever. About two-thirds of the way from the leading edge to the trailing edge, there was a dark feature of indeterminate shape in the NEB. It was quite persistent, though, and it rotated noticeably while I observed the planet.

11:15 p.m. 26 November 2001 (2001–11–27–0715 UTC)

I've recently taken to leaving Opus all set up, in the hopes that this will induce me to take it out more often. It certainly worked last night, as the 5-inch SCT went out for just a 30-minute session.

What I wanted to take a look at was Comet Linear, then hanging off the lower end of Aries's horn, a few degrees to the southeast of gamma Arietis. With the Moon fairly close by, I made good use of PleiadAtlas. (I could have brought out my new Uranometria 2000.0, but it was too windy.) Using the coordinates from the Sky and Telescope web site, and interpolating for November 27.3—I can't input comet elements to my atlas program yet—it was a breeze to find, although fairly dim in the midst of natural and artificial light pollution. After searching around for some comparison stars, I came up with a totally unscientific guess of about magnitude 6.2, or over a half-magnitude dimmer than predicted by Sky and Telescope. Well, I can blame it on the Moon.

There was also an even fainter tail that was barely detectible at 12 mm on the zoom (about 100x), extending up to the east-northeast. I guessed that the part I could see was about 15 or 20 arcminutes in length, but there's probably much more to it.

Since I had the telescope out, I decided to try for Jupiter and Saturn, so I pointed the telescope to Aldebaran for a fine collimation. No point—that star was blurred to at least about 3 arcseconds; I'm sure this represents the worst seeing I've experienced at home in about a year. Saturn's rings were completely featureless most of the time; maybe 10 percent of the time, I could tell that the inside was brighter than the outside. Jupiter revealed three belts (NTB, NEB, and SEB), and little else; I couldn't even identify which of the four satellites was which.

That was unsatisfying, so for my last target, I tried M78. Not bad for an 87 percent illuminated Moon. Under these circumstances, my best view was at 10 mm (about 130x), which corresponds to an exit pupil of about 1 mm. I could make out the two brightest stars of the associated cluster; I think these are about the 10th magnitude. The hazy patch of M78 itself, about 5 arcminutes in width, which was only visible by averted vision. With direct vision, I could see a brighter, elongated sliver, oriented roughly north-south and running through those two bright stars.

Out to the backyard and back in, a quick session, just 30 minutes—it's like guerrilla astronomy!

Copyright (c) 2001 Brian Tung