My Observing Log: May/June 2005

8:30 p.m. 8 May 2005 PDT (2005–05–09–0330 UT)

I set up the telescope early in the evening to let the optics cool down, hoping the seeing would be reasonable. Somewhat to my surprise, it was: about 1 arcsecond, and slow, too, so that I could watch the features on the gas giants sway to and fro, like seaweed in the ocean. I started out with Saturn. There was some ground seeing, generated by my house, which Saturn was over, so that detail in the rings was a bit washed out. I could make out no unambiguous sign of the Encke minimum. The crepe ring (Ring C) was of course easily seen in front of the disc, and could be followed indistinctly away from the disc. It is too dark to make out clearly.

Jupiter, far from the house, was better. The GRS, which I've been unlucky enough to miss thus far this apparition, was about 30 minutes past central meridian by the time I trained Opus in its direction, so it was just left of center (in the left-right reversed view of the SCT). I was able to make out three festoons: the largest one just north of the GRS, and two other, smaller ones about 30 degrees in longitude on either side of the big one.

12:40 a.m. 12 May 2005 PDT (2005–05–12–0740 UT)

The seeing this night was worse than last time; that often happens when I wait too long to set up the scope. Seeing is known to get worse as the night wears on. I'm not exactly sure why that is—I suppose I should find out, since I'm proposing to write a book on telescope optics in which turbulence and seeing is one of the chapters! This time, the seeing was about 2 to 3 arcseconds, and noticeably faster than before, too, making fine detail next to impossible to see on Jupiter. Saturn had already set behind the house, so that wasn't an issue.

I decided to go for some bright galaxies. First was M51. The Whirlpool is not tremendously difficult to find, but the small size of the C5+, the fork mount, and Ursa Major's low position in the sky all conspired to make it physically hard to reach. All the same, it was obvious when I found it: it was faintly but clearly seen. What was not so easy to pin down was M51's companion, NGC 5195. At times it seemed visible, but since I know it's there, I can't say for sure that I wasn't deluding myself.

Much more obvious were M81 and M82. These were higher in the sky, and therefore easier to get to than M51 and friend. M81's bright core makes it easy to see, even under bright suburban skies. I would say that the core seemed to extend perhaps a quarter to a half a degree; it's hard to say exactly where it ended and the sky glow began. M82 is considerably dimmer, but its thin, irregular shape makes it just as unmistakable as its larger partner. I tried to make out any indication of its dust lane, which under darker skies is easily visible even at lower magnifications. At 52x with the 24 mm Panoptic (the eyepiece used for the galactic observations in this session; I used the 6 mm Radian for 210x on the planets), the lane was definitely not visible with direct vision, and only glimpsed uncertainly with averted vision. I wouldn't swear to seeing it, but M82 did seem split in two.

11:00 p.m. 5 June 2005 PDT (2005–06–06–0600 UT)

It was partly cloudy tonight, with lots of high haze, but since it had been a while since I had stepped out at night with Opus (I've been out a number of times during the day with the Wocket and the Solar Max filter, though), I decided to set up as soon as everyone else was asleep.

The seeing was about average, ranging from 1 to 2 arcseconds and reasonably slow. First up was Jupiter, since I wanted to get a look at it before it sunk too low. When I started, the GRS was just starting to become visible toward the following limb of the disc. The hollow marking the location of the GRS was quite distinct, especially at 52x, but the Spot itself was not obvious at that low power, being better seen at 210x.

I followed the GRS for a half-hour, to the point that it was reasonably close to the center meridian and well placed. Even at that point, the GRS was not easy to confirm. One more thing that I observed in contrast to previous years was that the GRS seems less salmon colored and more greyish.

Elsewhere, there were two small festoons, one near the CM and another about 30 degrees toward the preceding limb. The SEB showed some mottling on the northern edge, preceding the GRS—perhaps indicative of the ovals and turbulence there? I don't know what the current state of the SEB is at high resolution, so I'm not sure how to interpret what I saw.

I tried looking at some bright DSOs, but it was just too hazy. M13 was reasonably easy, and I was even able to make out some granularity and jets of stars to the south and west, but M57 was just a barely seen disc, with no clear central hole, not even with the UltraBlock (narrowband filter), and M4 was barely visible at all. It took me about five minutes to be sure I was even seeing the great Scorpius globular. I hunted around for M80 for a couple of minutes and decided I probably wasn't going to be able to make it out (and even if I did, I wouldn't be too happy about it).

9:00 p.m. 17 June 2005 PDT (2005–06–18–0400 UT)

After about a week of the marine layer coming in just around dusk (and thereby frustrating my attempts to get any nighttime observing done), I finally got some clear skies. In spades, as it turned out.

I set up the scope around 8:00 to try to get a decent view of Jupiter. It took a little while longer than I expected for Opus to cool down, and I didn't really get any decent observing of Jupiter until 9:00. (This was at 210x with the 6 mm Radian.) At that point, the GRS was still three hours away from crossing central meridian, so it hadn't even crept out onto the daytime side yet.

The seeing was about 2 arcseconds, and moderately fast, but still slow enough that I could see it moving from south to north. (Down to up, in other words.) In contrast to previous observing sessions, in which there were few festoons, on average, there were no fewer than four festoons in evidence tonight, with the first and third (counting from preceding to following limb) more prominent than the second and fourth. They made quite a sight. In the SEB, just to the following side of the central meridian, there was what I thought was a notch on the southern edge of the belt. Perhaps it was an oval? The seeing was not sufficiently good to tell in the small scope.

One other thing I noted was that the belts were more similar in color than I had ever seen them. During my first Jupiter apparition in 1997–98, the belts were quite different in color, with the NEB being much redder (or more orangey, perhaps) than the greyish SEB. Now, the difference seems much smaller than before.

I also wanted to do some DSO hunting. I switched to the 24 mm Panoptic (52x) and tried warming up with some easy globulars, M4 and M80, but M4 proved to be very hard to see, as it was still rising. I deferred those for a moment.

The sky looked to be promising (for a light-polluted location, anyway). Albireo beckoned; it was the first nighttime target I ever pointed the C5+ at. Even now, seven years on, it's still a great sight. With a background of dimmer stars, the 68-degree panorama has a three-dimensional appearance to it, the yellow-blue pair standing out from the dim crowd.

With Aquila now up out of the horizon haze (this was about 11:00 local time), I pointed the scope at M11. What a beautiful sight this incredibly rich open cluster is. Under light-polluted skies, it's hard to tell this cluster from a very bright globular. Maybe the sharp angle near the eighth-magnitude star is a giveaway. The angle seems to me to be more than 90 degrees, closer to 100 or 110, although perhaps that's an illusion, resulting from the fact that that star isn't quite at the corner but grab's the eye's attention. What do others think about that?

My first new target was NGC 6755, in Aquila. This smallish open cluster can be found by drawing a line from theta Aquilae, through delta Aquilae, and extending it about a third of the way past. It's listed as being a quarter of a degree across. I found a handful of tenth- and eleventh-magnitude stars; I couldn't tell if there was anything deeper (although I strongly suspect there is). It's probably just not an appealing target in suburbia.

Better were two clusters in Vulpecula. Before heading to those, I checked out M27, the Dumbbell Nebula. Amazingly bright, even under these skies. Stands out like a sore thumb, and even without a nebula filter, it shows some texture to it. It lies off 14 Vulpeculae, the center star of a distinctive W or M pattern.

Off the western star of the W, 12 Vulpeculae, is the first of the two Vulpecula open clusters I observed, NGC 6830. This is a small open cluster, just 6 arcminutes across—a tenth of a degree. The Vulpecula W/M pattern has a couple of wide doubles in it, and NGC 6830 is embedded in a smaller, dimmer equilateral triangle of wide double stars. It's a pleasing asterism in its own right. The cluster lies on the northern edge of the triangle, a bit off center. It consists of a few tenth-magnitude stars, but unlike NGC 6755, there is a distinct sense of some dimmer stars lying just outside individual detection, registering only as a granular haze. Not a bad little cluster, and one I'll make a note of looking at when I next get under dark skies.

Following along the same line from M27 to NGC 6830 is NGC 6823, which lies an equal distance away. I've actually observed this one before, about a year ago, on a suggestion from Bill Ferris. It's also pretty small, listed as only an arcminute wider than NGC 6830. It sits at the apex of a wide angle made of four stars; interestingly, just a fraction of a degree away is a smaller angle of three stars, exactly parallel to the first, so that the pair make a kind of chevron. Another provocative asterism. This cluster has a bit less depth than NGC 6830, but there is still a sense of some dim member stars behind the first several tenth- and eleventh-magnitude stars.

By this time, the sky had darkened significantly—dark enough and steady enough that the Double Double, epsilon-1,2 Lyrae, was visible to the unaided eye as a tight pairing, just over three arcminutes apart. Many times in my backyard, I can't distinguish them, only because the sky is too bright for their light to be made out quite directly. But tonight, it was no problem. I estimated the zenith limiting magnitude to be over 5.0, almost unheard of in Santa Monica. At 52x, each pair of the DD was just barely split, with the southern pair (the more equal one) more easily so.

M4 and M80 were now quite easy to see, and M4's central north-south bar and granular appearance were fairly straightforwardly discernible. I was encouraged to seek out another globular further westward, NGC 5897, but unfortunately, that cluster was only 17 degrees from the waxing gibbous Moon. I found the exact spot where the globular should be, but try as I might I couldn't make it out at all.

Last but not least, I pointed the scope at Jupiter again, now setting in the west. The GRS was now sitting at central meridian, and even at only 52x, the GRS hollow could be made out. I couldn't see the GRS itself at that low power, though.

Copyright (c) 2005 Brian Tung