My Observing Log

Scroll to the most recent observing session.

My log has been so intermittent in the last five years that I'm giving up the ghost in terms of grouping the reports in bimonthly sections. When I finally get back to observing regularly, I'll go back to that scheme; for now, everything recent will go here.

7:45 p.m. 18 February 2009 PST (2009–02–19–0345 UT)

It'd been so long since I took Opus out that he had gotten blocked in the garage behind our old washing machine (broken transmission) and some paint cans. It didn't take long to free him, though, and the great thing about having it otherwise set up is that I can be observing in just a couple of minutes. Remove the caps and slip in an eyepiece, and I'm all set.

For the first time in a while in my backyard, it was clear and mild, in the mid-50s, I think. (That's in the low teens for you metric folk.) My younger son, I knew, would find it interesting that his dad had set up the telescope, so I had it pointed toward Venus first, still up but sinking fast over the house in the west. As I also knew, at high magnification (the 6 mm Radian for about 210x), he would confuse it with the Moon. But he understood when I told him that the Moon wouldn't rise for quite a few more hours yet.

Heat waves off the house made it impossible to even try to see any detail in the cloud decks, and I'm not particularly blessed with great near-UV acuity. The substantial crescent was worth it just the same. It'll get even thinner and longer in the coming weeks, but it will also set earlier and earlier until it reaches inferior conjunction.

Next was M42, just to see if he could make it out. And sure enough he could. I tried to get him to count the number of stars in the "cloud" (meaning just the Trapezium), but he was intimidated by all the stars in the field and couldn't focus long enough to do it. But it was neat just watching him make out the nebula at all. Looking up from the eyepiece he also wanted to know what star was up there "next to the garage." (It was Capella.)

After that he went inside and it was on to a short but semi-serious observing session. First up was NGC 1907, a small open cluster just south of M38 in Auriga's distinctive polygon. It's about a third of the way from beta Tauri to Capella. Alternatively, two small but obvious three-star chains in Auriga's southern half point a winding path toward the two clusters. NGC 1907 is small but easily seen, even with direct vision in moderately light-polluted skies (ZLM about 4.8 with 20/15 vision). With averted vision it shows an east-west elongation, about twice as long as it is wide, and perhaps 20 to 30 stars visible.

My other target was NGC 2175, an emission nebula just off from chi-2 Orionis at the northern end of Orion's club. This didn't make Messier's list (possibly because it's unlikely that he would have confused this with a comet, but one could make that argument about any number of objects that did make his list), but it's certainly bright enough. Its high position in the sky did make things easier, but I still rate it less difficult to see than M1 (the Crab Nebula). Most obvious (but not really easy) was the M-shaped edge to the nebula radiating off from its central star. It is also rather sizable: At about 50x with the 24 mm Panoptic, the nebula covers a substantial fraction of the field of view, perhaps a third to a half a degree wide. It also seemed to have a grainy texture to it, though that might just have been trying to see detail in a dim nebula at the limits. I did not try using a nebula filter—next time perhaps.

12:05 a.m. 24 February 2009 PST (2009–02–24–0805 UT)

I read about the Saturn quadruple transit on one of NASA's pages. It occurred to me briefly that I might stay up to see it, but after a while I decided against it. Just too little sleep. But that didn't mean an observing session was out of the question.

First up was NGC 2266, a small open cluster in western Gemini. It's just a bit north of epsilon Geminorum, and can be found nestled in the southwestern quarter of the bowl of a little miniature Big Dipper (mirror reversed), complete with seven stars. It extends northeastward from the analogue of Phecda (gamma Ursae Majoris) perhaps five or so arcminutes. It was not tremendously easy under these skies—some high mist lowered the ZLM to maybe 4.5 or 4.6—but neither was it very difficult. It revealed perhaps a dozen or so stars using averted vision, with the promise of perhaps a dozen or so more just beyond the magnitude limit. It is elongated slightly along a northeast-southwest axis, perhaps half again as long as it is wide.

Next up was delta Geminorum, next to which Pluto was discovered back in 1930. It is a fairly unequal double, magnitudes 3.6 and 8.2, separated by 5.5 arcseconds. At that distance it should still be a fairly easy split, but try as I might, I could not make out the secondary. Part of the problem was that the seeing was still mediocre, and the stars were now setting over the house, meaning that rising heat was adding to the image instability. I decided to go ahead with some other targets and come back to delta if time permitted.

I hadn't seen Saturn through Opus yet this apparition, so I pointed him that way. The rings are, of course, much closer to edge on than I have ever seen them before: I bought Opus in 1998, when the rings were already a bit further open than they are now, and only getting more so. I must say that I prefer the rings wider open, although it was neat to see them this flat. The easiest feature to see was the shadow of the rings on the disc of Saturn. I thought I could also make out the relatively white shade of the rings themselves in front of the disc, just next to the shadow, but I might be deluding myself. Continuing in the possible delusion department, I thought I spied a slight darkening in the following half of the southern hemisphere. Anybody concur or deny? Finally, I could make out the slight separation between the front and rear halves of the rings just on either side of the planet's disc. The seeing was not good enough to see this as actual black; it appeared instead as a distinct darkening between the bright halves of the rings.

Having failed apparently with delta Geminorum, I tried gamma Leonis, which has a smaller separation (4.6 arcseconds), but brighter and less unequal (magnitudes 2.4 and 3.6). This was a pretty easy, with a position angle in the neighborhood of 135 degrees and pretty similar golden color, making me think that perhaps I had made a mistake with delta Geminorum. A quick look at the atlas revealed my problem; I had somehow confused delta with zeta. Correcting that mistake did reveal the dim secondary to delta, but it was still harder than I thought; the air turbulence (rather than proximity to the primary) smeared out the light of the secondary, making it much harder to see. It appeared to have a position angle of about 240 or so.

The last target of the night was Comet Lulin, which was just in the neighborhood, only a couple of degrees from Saturn and sigma Leonis. In fact, not knowing exactly where Lulin was, I just started from Saturn and swept east and west. The comet was easy—surprisingly easy—to find even in the light pollution. I estimate its brightness at about the fifth magnitude. It is maybe 15 arcminutes by 10 arcminutes (although I wasn't really trying to make an accurate estimate; this is just a rough impression), elongated perhaps east-northeast to west-southwest. It was west-southwest of Saturn, about two degrees away, with sigma Leonis in between, about a fourth of the way from Saturn to Lulin. Of course, by the time you read this, it will have moved on. I did not make out any distinct central brightness, although I didn't really make much of an effort to do so.

10:45 p.m. 24 March 2009 PDT (2009–03–25–0545 UT)

I've been meaning to get out for a couple of nights, but this one was the first one where it wasn't too windy out and my allergies weren't acting up. By the time I got set up, M42 was already only a degree or so from setting over the roofline of our house (the backyard patio where I set up is east of the house), but I still decided to point it that way to have a look. As I expected, there was too much turbulence from the latent heat over the roof to have a chance at resolving E or F, but the Orion Nebula is always worth a good look. Even with the turbulence the nebula itself is still full of interesting detail at 50x.

From there it was over to M51, the Whirlpool Nebula, the first galaxy to show a spiral nature (observed by Rosse in the late 1840s). This was the first time I'd ever tried to observe the Whirlpool this early in the year; normally, by the time I give this a try, it's either overhead or beginning to set in the northwest. This time it was still medium high in the east. I had an unusual amount of trouble finding it, which might have had something to do with it being suspended in the light dome over L.A. Normally, I'm able to find the right spot in the finder, but this time, I had to star-hop from 24 Canum Venaticorum in the eyepiece. Even at 50x this was something of a chore, though not an entirely unenjoyable one. Even when I had it definitely in the field of view, it was not an easy detection. There was no question of finding its partner (NGC 3195) in the mix. So perhaps the light pollution did have something to do with it.

After that came my first new target of the night, NGC 3242, the so-called Ghost of Jupiter. Except that I didn't think it was new; I was sure that I had seen it before. But a quick text search of my observation logs doesn't show a reference to either NGC 3242 or the Ghost. Again, this was a bit tricky to find in the light-polluted sky. I'd estimate the limiting magnitude to be maybe as much as a half-magnitude lower than in previous sessions, and Alphard (alpha Hydrae) was the only star easily visible to the unaided eye in that general area. I used that as a starting point and was able to star-hop in the finder most of the way. Once there, though, it was easy to see. At 50x, it took a second or two for me to cotton on to its non-stellar nature. I switched the 24 mm Panoptic out for a 6 mm Radian with a narrowband filter. The seeing was not tremendously good (perhaps a couple of arcseconds of blur), but the Ghost is a bit fuzzy to begin with, so perhaps it didn't matter so much. It was clearly elongated somewhat along a northwest-to-southeast axis, with three or four knots of light arranged along this major axis, bent slightly to the southern edge, almost as if we were seeing an equatorial string of lights along this Ghostly Jupiter, seen from high above a temperate latitude.

After that, I didn't expect much from Saturn, given the seeing, and so I managed not to be too disappointed. No real cloud structure could be seen, aside from some subtle banding. The rings are almost edge-on now, of course, except that their inner edge, first in the crepe ring and then in the empty space inside that, could be seen as a dimming in the overall profile of the rings. I observed Saturn at 130x, the 6 mm Radian with the f/6.3 focal reducer. I figured that would help with any troubles I was having navigating the light-polluted skies.

My real reason for going to Saturn was as a setting-off point for my last target (and second new one) of the night: a double star just over the constellational boundary, 40 Sextantis. I tried first at 32x (the 24 mm Panoptic), and then at 130x, but I could not split it either way. So I tried something I've done in the past, which is to slip in the 8–24 mm Vixen zoom, because sometimes details can only be seen within a relatively narrow band of magnification. I started at 16 mm and worked my way down toward 8 mm. Only as I got down toward the 8 mm to 10 mm range (about 100–130x) did the split become relatively straightforward to discern, although whether it was because of that particular power or a momentary improvement in seeing wasn't clear. At any rate, I estimated the position angle at 20 degrees (the actual figure according to Ridpath and Tirion is 13 degrees). The separation is supposed to be 2.3 arcseconds but it seemed tighter than that to me.

12:30 a.m. 21 July 2009 PDT (2009–07–21–0730 UT)

I first heard about an impact on Jupiter from the amastro mailing list (it's a Yahoo group, I believe). At first, not too many people were actively discussing it—just Brian Skiff and Greg Crinklaw. Greg posted a very brief ephemeris, indicating that the impact mark should cross the central meridian at around 12:30 a.m. PDT, Monday night into Tuesday morning. I took a look at where Jupiter was at around 11:30, but it was still too low in the sky for it to make much sense to observe yet.

About an hour later, Jupiter was, if not exactly high in the sky, then at least high enough to make it potentially worthwhile. The last time I observed, I adjusted the finderscope to put it in line with the OTA, and it definitely helped me nail Jupiter on the nose, even at 130x (6 mm Radian with the f/6.3 focal reducer).

Initially, the image of Jupiter was too unsteady to see much of anything on the disc beyond the two equatorial belts and the southern temperate belt. Much of that turned out to be heat from the tube, though, and after about fifteen minutes, the image was much steadier. The seeing was mostly slow, crossing Jupiter's disc every second or two, and about 2 arcseconds in amplitude. Every now and then, there would be a quick blur of several arcseconds, but as if to compensate, there would follow a quick lull of sub-arcsecond seeing. Most of what follows draws from those moments.

The northern equatorial belt showed a few festoons, mostly in the preceding half. The southern equatorial belt showed substantial bifurcation, and the southern temperate belt had a barge, also in the preceding half. And just as Greg had predicted, there was a small, dark oval smudge in the southern polar region, at perhaps 60 degrees south latitude, just past the central meridian. It was larger than I had seen in the earliest photos, maybe one-third the size of the Great Red Spot and similarly proportioned. It was not distinctly dark, although that could have been a mixture of diffraction and some residual atmospheric turbulence. It seemed to me about as dark as the Cassini division in Saturn's rings.

Since I had missed observing the Shoemaker-Levy 9 impact in 1994 (I didn't really return to astronomy until about 1998), this was my first opportunity to witness an impact event, and it was well worth it.

11:45 p.m. 6 August 2009 PDT (2009–08–07–0645 UT)

The Full Moon is not usually the best time to do deep-sky observing, but its effect can be made less significant by concentrating on objects with some higher peak surface brightnesses, like open clusters, planetary nebulae, multiple stars. I observed one of each on this night, and each of them a new target for Opus. The sky, in the darkest part in the north, was perhaps limiting magnitude 4.3, but in the south, near the Moon, it was much lower than that.

First up was the open cluster NGC 6774. You can navigate to it in a number of ways. I found it by starting from second-magnitude Nunki (sigma Sag, at the top of the handle of the Teapot), going through fourth-magnitude omicron Sag (which lies near somewhat brighter pi Sag), and then continuing on an equal distance or so. This should get you to within a degree or so of the proper spot. In darker skies, it's probably easier to start from fourth-magnitude rho-1 Sag, but I was finding that difficult to see in my skies, especially with the nearly Full Moon out in force. A bit of adjustment in the finderscope was sufficient to put me on my target.

At 32x (24 mm Pan with an f/6.3 focal reducer) shows a pattern akin to a pair of ram's horns, about a degree or so across and opening up to the north. NGC 6774 is located at the vertex of these horns. Under these skies, it was difficult to see much detail directly, although there seemed to be a gauze of perhaps 30 stars of around the 11th magnitude, somewhat elongated north to south, and evidently a little offset to the west.

My next target was the planetary nebula NGC 6818, nicknamed the Little Gem. It certainly is small, measuring maybe 15 or so arcseconds across. I found it similarly to how I found NGC 6774—by starting at third-magnitude Kaus Borealis (lambda Sag, the tip of the Teapot), going through third-magnitude pi Sag, and then moving on an equal distance, plus a little bit north. Again, this got me to within a degree or two of my destination. In the finder, the Little Gem is nestled within a loose grouping of several fifth and sixth-magnitude stars.

At 130x (6 mm Radian with the f/6.3 reducer), NGC 6818 is small but evidently non-stellar. I'm sure it would have been more obviously so if the skies were darker. With the Orion UltraBlock filter, it became still more obvious; it took a while to refind focus, though, since the Radian is long enough to touch upon the bottom end of the diagonal barrel. (Didn't hit the mirror, though!) The nebula seemed slightly elongated north to south, as the cluster was. There was no clear tint to the nebula without the filter; obviously, with the filter, it was blue-green (but then so was everything else!).

The last target for the night was Struve 2375, a tight-ish double in Serpens (Cauda). It can be located at the fourth corner of a parallelogram completed by third-magnitude zeta Aql, delta Aql, and lambda Aql. This was strangely harder for me to find than the other two objects, possibly because it was higher in the sky at the time and the last bit of pointing adjustment required me to look up through the finder. (Could be I'm getting older…) About a degree and a half to the west is the open cluster IC 4756, which is marked by a sixth-magnitude yellow star but consists of a dozen or so ninth-magnitude stars plus a smattering of tenth-magnitude and dimmer stars.

Once I found it, Struve 2375 was easily split; the seeing was pretty good, about an arcsecond or thereabouts, and mostly slow. The secondary was easily seen to be slightly dimmer then the primary, and I estimated the position angle at 115 to 120 degrees; I later confirmed it at 116 degrees, so I was pretty close on that. (I estimate these by making sure I look through the eyepiece directly behind it, rather than off to the side; then the OTA is in the direction of PA 0 degrees, one o'clock is 30 degrees, two o'clock is 60 degrees, and so on. This works like this only with the diagonal in place.)

Interestingly, both stars in Struve 2375 are themselves doubles. They are both splittable in principle, but the separations in each case are very tight, about 0.15 arcseconds, beyond the reach of all but the largest amateur telescopes in the steadiest of atmospheres. In the 50 or so years since the additional stars were discovered, they have shared a common motion across the sky, so they are almost certain to be physically associated.

7:00 p.m. Sat 19 Sep 2009 PDT (2009–09–20–0200 UT)

For the first time in a while, I made it out to Lockwood for a dark sky party. I went with a friend of mine Dennis who just got into astronomy over the last year, but is really into it. He's actually a member of LAAS and went out to Lockwood in May, when it was pretty cold (apparently it got down into the 20s). It was a lot warmer this time; I don't think it got any colder than 45 or so.

We left around 4:20 or 4:30; we had wanted to leave around 4:00 but I couldn't get my act together in time for that. Part of it might be that I decided to bring both Opus and the 10-inch Starsplitter dob (which I used to call Snuffleupagus, but I'm now thinking maybe I should call Cutter John!). I also decided for the first time to bring Burnham's three volumes as a field guide; I realize a lot of folks think that's a dicey choice as a field guide, but I wasn't really keen on covering a lot of ground, and Burnham's is great for passing the time while the sky grows dark. Good thing we were taking Dennis's Jeep. I think we could have fit everything inside my Prius, but it would have been a bit of a squeeze and I would have had to take out the child seat in all likelihood. I also would have had to figure out something to do with the alarm light, which is yellow, unfortunately, and would ruin night vision and possibly imaging for folks.

We got into the site around 5:50, with still about an hour to go before sundown. We spent maybe half an hour getting set up; I realized then that I had forgotten my seat. Dennis had his chair which he loaned me for most of the night, since he wasn't really using it once the observing got under way. He also donated a couple of batteries to my Telrad. In return, I gave him a couple of nice eyepieces as long-term loans, so it's not as though he got the short end of the stick in that regard!

Not surprisingly, Jupiter was the first thing to poke its head out. We had known (using PleiadAtlas) where it would be, more or less, but had no luck finding it as the Sun went down. A few minutes later, we were saying we couldn't find it, and someone said, "Oh no, it's out." And sure enough, there it was, unmistakably! Amazing how rapidly the sky gets dark enough at that time. I pointed Cutter John (we'll see how long this lasts) at it, but only at low power: a 55 mm Plossl for about 27x. Even at that magnification it was evident that the seeing was still pretty bad, as it often is at Lockwood. The view in Opus, at 130x, through a smaller window of air, wasn't noticeably better. I could make out the bands and the satellites and that was about it.

But rapidly enough the sky got dark and impressive and we got down to some serious dark sky observing. I spent the first hour or so just getting reacquainted with the look of the rural sky. Cutter John's mirror is very dusty, which might have contributed to a gentle haze surrounding most of the stars. The haze would have been there around all of the objects, too, but it was harder to tell there. Lots of old favorites: the Dumbbell (M27), the Ring (M57), the Wild Duck (M11), a couple of the Sagittarius globulars (M22 and M26), Albireo, etc. Most of these were seen by Opus with a 24 mm Pan with a focal reducer (for about 32x).

I did look at two new objects, NGC 7217 and NGC 7006. The former is a spiral galaxy seen about 80 percent face on. You can find it by starting at Scheat (beta Peg), a red giant at the northwestern corner of the Square. Follow that out of the square to the northwest to Matar (eta Peg), and then continue in that direction to pi Peg, a loose double star. About two degrees south of that is NGC 7217, nestled in a longish trapezoid of tenth and eleventh-magnitude stars.

The spiral structure is very subtle; there are no real arms to be seen even in many long-exposure images. Needless to say there were none to be seen visually, either. Part of that might have been that I never went away from the 55 mm in the big scope, so it never got above about 27x or so. But even so I have serious doubts about being able to see much detail in the structure of this galaxy. The thrill is mostly in the hunt on this one, as it is for NGC 7006, which along with NGC 2419 (the so-called Intergalactic Wanderer in Lynx), is one of the most distant globulars surrounding the Milky Way. Both were suggestions gleaned from Burnham.

NGC 7006 is in Delphinus, just a few degrees to the east of gamma Del, the orange-ish star marking the dolphin's snout. There are a few line-of-sight doubles marking the way from gamma to NGC 7006, which is bracketed on its southern side by two seventh-magnitude stars. Again, not a lot of structure to be seen here, although I did catch a glimpse of some star trails, visible more as a bias in the brightness than anything really distinct. Not much of a central condensation in this one, at least not that I could see. But what was very neat was that once I found it (or NGC 7217, for that matter) in Cutter John, it was simple to find and see in Opus—surprisingly simple, actually, although again, that might have been a function more of the dust on the ten-inch's mirror than any particular aspect of the objects or environments.

Mostly it was enjoyable just to sit back and get back in the swing of observing. At some point later in the evening, I went into the trailer to microwave a bag of popcorn (took a lot longer with their microwave than it does at home!) and recline in Dennis's chair and watch the constellations roll slowly by. Dennis was getting cold so we started tearing down about 11:15, but it was still a good night.

6:00 p.m. 19 December 2009 PST (2009–12–20–0200 UT)

Tonight, my good friend Andrea joined Dennis, myself, and my kids out to Griffith Observatory, which was hosting the LAAS December public star party. It's been partly cloudy all week (which I not so secretly think is the weathercasters' way of saying, "We have no good idea what's going to happen"), and that continued on into the session tonight.

I first brought the Wocket with the H-alpha filter (the pre-Meade Coronado SM40), and that yielded pretty good views with a couple of minor prominences and some small filaments to be seen. The most obvious of the prominences was one on the preceding edge, a vertical jet topping out at perhaps 70,000 to 100,000 km off the limb.

In time, however, the clouds gathered along the horizon in the ubiquitous marine layer that inhabits the Westside of Los Angeles, and even that prominence was lost to haze. So we packed up the Wocket, but after a trip inside the planetarium to see that afternoon's show—about water, its role in the evolution of life, and prospects for finding it on other worlds—I brought out Opus and Dennis brought out his 4-inch refractor (as yet unnamed, as far as I know).

There was unfortunately not much to see other than the Moon and Jupiter. I say unfortunately because once again Griffith Observatory delivered another of its nights of fabulous seeing: decidedly sub-arcsecond and providing for exquisitely detailed views of Jupiter. The Great Red Spot was just vanishing off the following limb in the SEB as we began, but the festoons off the NEB were crisp, if a little muted by the persistent thin clouds. At no point did the image seem even to quaver at 130x.

Despite the scarcity of targets in the sky, we did have a fair number of people show up to the party. For an hour or two as both Dennis and I switched back and forth from the Moon to Jupiter and back, there was a constant line of people queueing up to take a look. A few asked pointed questions about how much the telescopes cost (I told them, but also let them know that they're actually cheaper now than they were then, for the same optical quality and more whizbang gadgets), and a few more asked questions about how far everything was. Just one more indication that folks are only too ready to join the ranks of amateur astronomy.

11:50 p.m. 14 February 2010 PST (2010–02–15–0750 UT)

I really do have to get out a bit more: This was both my and Opus's first trip out to see Mars this apparition. The seeing in my backyard, which unlike Griffith Observatory isn't situated high atop a hill, was not as accommodating as that worthy, but it still permitted some decent detail to be seen.

As usual, I like to make at least one observation before checking with reference sources, so I pointed Opus up at Mars, higher in the sky than I have ever seen it through a telescope, and started taking notes. The first detail to be seen, quite easily in fact, is the north polar cap. It's rather sizable (though perhaps not quite as large as I have depicted it in the sketch below) and the contrast is fairly strong, even with indifferent seeing. As the night wore on and the scope cooled down, the NPC got steadily easier to see.

Also emerging from the atmospheric turbulence were two main groups of dark markings. One cupped the NPC in the middle third of the northern hemisphere, and had a small protuberance toward the following limb. The other group was larger and spanned most of the bottom half to two-thirds of the southern hemisphere. I saw it rising in latitude toward the equator from following to preceding limb, terminating in a kind of "bottle nose" maybe 30 degrees beyond the central meridian.

The seeing was highly variable: At its best, it was maybe 1 to 2 arcseconds, but without warning it would gust up to 5 to 10 arcseconds, blurring the image continually. Mars observing tonight was definitely an exercise in patience. It took about an hour to complete a decent sketch of the planet.

After my initial notes, I used MarsMap, a PalmOS application I co-wrote with Akkana Peck of, I believe, the Fremont Peak crowd in the Bay Area, to get my bearings on what I had seen. It's been a while since I've checked the orbital constants against observations, so the values were a bit off: MarsMap indicated the central meridian should have been 17, but it was in fact about 13. My sketch, along with some prominent signposts, is shown below.

Mars on Valentine's Day

The view above is mirror reversed. The two main patches were Mare Acidalium in the north, and Mare Erythraeum in the south. The nubby protuberance in the north was Nilokeras, while the "bottle nose" in the south was Sinus Meridiani and its (areographic) eastward extension. It will be interesting to take another look at Mars in a week or two and see if the other side, with Syrtis Major (which for some reason I always associate with Africa), is just as photogenic!

9:00 p.m. 17 February 2015 PST (2009–02–18–0500 UT)

It hasn't really been five years since I took Opus out observing, but it has been five years since I wrote a report, I guess. So here's a report! Oddly enough, a lot of these reports seem to take place around the middle of February. I sincerely have no idea what that's about.

It had been a while since Opus had been out, though, so he required a bit of sprucing up. The corrector plate, notably, was covered with a layer of dust that had adhered somewhat. There was no question of fixing that with the LensPen, so I took some Windex and cleared off most of it, leaving the last bit of touch-up for the LensPen. (Lens surfaces are coated and should be resistant to careful cleaning; telescope mirrors, on the other hand, are first-surface and too delicate to clean this way.) Opus also needed some collimation, but the amount needed was quite small. The stable storage he's in may account for that.

I also took off the focal reducer, which had been attached to Opus for goodness knows how long. It's very good for nice views of broad targets, but I knew that I would be observing only small targets today, so I took it off and allowed the rear port to breathe freely, so to speak. I also used only the 6 mm Radian, yielding 210x.

Once I began observing in earnest, I looked at three targets throughout a period of a couple of hours, cycling back and forth amongst them. It was slightly more difficult to get them into the main field of view than I would have liked, owing to my "new" right-angled 8x50 finder. (It's actually a couple of years old. That's incidentally why I know I've used Opus more recently than five years ago: because I've used him with the finder.) It seemed more difficult than it should even to get targets into the finder. I realize the field of view is smaller than with the lower-magnification finders I've used previously, but it didn't seem that it should be that much more difficult.

My first target was Jupiter. I didn't prepare myself in any way for what was going on with Jupiter, and chanced upon a central apparition of the Great Red Spot. It was following the central meridian by a half-hour or so when I first looked at it, and I was able to follow its progress across the southern face of Jupiter as the night deepened. The transparency was indifferent, but the seeing was good, rather better than the usual for this location. Jupiter looked impressively large, in part because of that steadiness; bad seeing tends to make detail more difficult to see, naturally, which in turn makes Jupiter look smaller, subjectively.

As the air in the telescope settled down, I could distinctly make out a shadow of one of its satellites in the preceding half of the equatorial zone. This later turned out to be Europa, unsurprisingly; about an hour or so into the session, the satellite itself appeared at the preceding limb of Jupiter. (The satellite itself is fairly light, and too difficult to see against Jupiter's clouds, the fairly good seeing notwithstanding. Maybe on an even stiller night, or with a larger telescope.) Proceeding outward away from the preceding limb were Io and then Ganymede. Callisto was obscured by the planet itself. I looked for surface detail on Ganymede, which I had previously observed with Opus, but I could see none.

Returning to the GRS itself, it was darker than I remembered it last, nearly as dark as the SEB. It was separated from the SEB first by a narrow band (perhaps a half-arcsecond to an arcsecond wide) of creamy white, and then by a darker section of the SEB, which led from the southern edge of the SEB just preceding the GRS, and then trailing up and over the remainder of the GRS. Two prominent festoons trailed equator-ward from the NEB, about one and two hours following the GRS, respectively. The STB was visible but with no distinct contrast with the surrounding zones, but the NTB was clearly delineated from its surrounding zones, with some barges visible on the southern edge.

My second target was Sirius, whose companion, Sirius B, is as far as it has been from Sirius during my observing lifetime, about 10 arcseconds. The difficulty, of course, is the brilliance of the primary. By way of comparison, Rigel has a companion of similar dimness (perhaps somewhat brighter?) and separation, but because Rigel is much dimmer than Sirius, I found Rigel B an easy mark this evening. I used it primarily to figure out how far Sirius B should be from its primary in the field of view.

I made several attempts to discern Sirius B, but never could be sure I had found it. I knew that it was either just north of west of Sirius A, or just north of east of it, but wasn't sure which, and partly on purpose, and partly accidentally, did not confirm which it was, just in case I might be deceiving myself. (In fact, I checked the planetarium program on my smartphone, and it seemed to indicate just nrth of east, but I seemed to recall reading it was just north of west in an article somewhere, so I wasn't sure. At that point, I decided I wouldn't check further.)

Part of the problem was that the seeing wasn't quite exquisite, merely quite good, but also possibly affecting B's visibility was the transparency. This wasn't an issue with Jupiter, of course, for the most part, but it could well obscure Sirius B. At any rate, I would go back and forth, sometimes thinking I had glimpsed something to the left (west, in the right-angled eyepiece) of Sirius, other times thinking I had glimpsed something to the right. Since neither observation was distinct or even more distinct, comparatively, than the other, we'll have to chalk that up as a negative observation.

Last, and certainly least observed, was the Trapezium. Even over the house as it was at this point, the view was fairly steady, with the main four stars clearly visible as discs at 210x. Again, possibly because of the transparency, I could not make out either E or F, and it seemed unlikely that I would do so, given that the contrast B and C offered with the surrounding sky was not great. Still, there is something rather grand about seeing even the central region of M42 covering the majority of the field of view, with its soaring wings of gas. It always reminds me of an eagle, its neck at the center of the nebula. I think that if I try for E and F somewhat earlier, when they are higher in the sky, they might be more easily visible.

11:25 p.m. 16 August 2020 PDT (2020-08-17-0625 UT)

Just planets today: Jupiter and Saturn. I have not taken Opus out in a long time--long enough that I don't even remember how long it's been. It has been warm, and people are running the air conditioning, so I didn't expect very good seeing. What I got was a little better than I expected, so the effort was rewarded.

I originally checked what Jupiter was up to two days earlier, around the same time of night, but by that time, the GRS was already rotating away from view. So I decided Sunday would be more ideal, when Jupiter would be "two hours behind" compared to Friday. Unfortunately, at about 10:00, we appeared to be clouded over. Fortunately, it was just a momentary obstruction, and by shortly after 11:00 local time, it was clear enough, if a bit hazy.

The seeing was fair, occasionally good enough to allow detail down to 1 or 2 arcseconds, but generally worse than that. Occasionally, the turbulence made it seem as though a plane had flown by, even though I didn't see one.

The GRS was just past the median (the imaginary vertical line drawn between Jupiter's north and south pole. It was a deeper red than I remembered, though to be sure it didn't look that saturated; I was partly correcting for the mediocre seeing. The equatorial zone was quite mottled, and I got the impression that if the seeing were better, there was a fair amount of detail there to be seen. Next time, perhaps.

Saturn is showing its rings to full effect these days, nearly fully wide open, and making the Cassini division relatively straightforward to make out, even given the atmospheric conditions. As usual, its cloud deck was much more subdued than Jupiter's.

By the unaided eye, the two giants make a pretty pair, separated by several degrees as they are every two decades. I couldn't help thinking about the last time they Jupiter passed Saturn, when Opus was mostly new. Well, there's still more to see from them this season, so perhaps next time I will see more and wax nostalgic less!

Copyright (c) 2009 Brian Tung