Slip Sliding Away
Observing notes from Saturday, August 31, 1996
Well, the skies finally cleared up enough to do some star gazing. Here in the south, if we are not having thunderstorms in the evening, the skies usually look like you are seeing them in a fun house mirror when you use the telescope. I was looking at Arcturus the other night and it looked like a pulsating, circular rainbow. While this is quite pretty in the eyepiece, and may even get a "wow" and "pretty neat" from your non-astronomer friends, it basically means the skies are worthless for any "serious" observing. But, the skies of August 31 offered somewhat better viewing conditions that the usual, so I set up the 8" f/10 Schmidt-Cassegrain on my deck.
After showering myself with insect repellent to ward off the infamous, and aggressive Southern Kamikaze Skeeters, I set about exploring the night sky. My first target for the night was that blazing beacon in the southern sky called Jupiter. Located in the constellation of Sagittarius, the king of the planets is very well place for observing right after sunset. When I first focused the image of Jupiter in my eyepiece, I thought of the title for these observing notes. The reason is that I found the Jovian moon Europa, just about ready to slide behind Jupiter's disk. I decided to keep my eye glued to the eyepiece, and watch this disappearing act. That was easier said than done. The "seeing" kept fluctuating. Sometimes I'd have a clear image, and then it would blur. I couldn't seem to keep my hand off the focusing knob. I was constantly tweaking it, trying to bring the image to perfection. On top of that, I also was switching eyepieces like crazy. I finally settled in, and watched as Europa slowly slipped behind Jupiter. For a while, it was just a "bump" on the side of Jupiter's disk. Then, it winked out.
As this was going on, another visual treat could be found on Jupiter's face. A total solar eclipse was in progress for anyone on Jupiter, along the path traced out by the shadow of Callisto, another one of Jupiter's moons. I'm sure if there were any Jovians observing this eclipse, they were definitely jovial. The shadow of Callisto was rather large and easy to see. I caught it very close to the central meridian. I love to watch the shadow transits because they affirm that the planets are active worlds. I returned to Jupiter throughout my observing session, to keep tabs on the shadow transit.
Since it was in the neighborhood of Sagittarius , I next aimed the scope at the globular cluster M22. Jupiter and M22 were both visible in a low power eyepiece a few weeks ago, but now Jupiter has moved away slightly. They both still show prominently in the finder scope. Shining at a magnitude of about 5.1, and with an angular size of about 24 arc minutes, M22 is easily to spot and resolve. It is a glowing ball of stars, too numerous to count. Although Sagittarius harbors some other fine globulars, M22 is the brightest, and ranks among the best seen from northern latitudes.
Next up on my observing list was the potential famous Comet Hale-Bopp in the constellation of Ophiuchus. This is the comet expected to put on a grand show next spring. I'll be satisfied if it just matches what Comet Hyakutake did. Comet Hale-Bopp shows as a large glow with a bright condensation in the middle. The coma is somewhat fan shaped. Some are reporting a tail, but I couldn't quite convince myself of that. My skies just weren't good enough for more details.
Since I was in an area of the sky rich with deepsky wonders, I decided to add a new object to my observing list. That new object was the globular cluster M28 in Sagittarius. Glowing at a magnitude of about 6.9 and with a size of about 11.2 arc minutes, it's about half the size of M22. Although I could somewhat resolve the pinpoints of stars contained in the cluster, M28 still offered a dim view compared to M22. This dusty region of the galaxy knocks a magnitude or two of brightness off of the cluster. Nonetheless, globulars remain as my favorite deepsky objects.
Next up on the list was M8, the Lagoon Nebula, also in Sagittarius. M8 is a large nebula and cluster of about 90 arc minutes in size, with a magnitude of 5.8. The dark space, or "lagoon" was visible with averted vision, quite easily. This must be a truly remarkable sight from dark skies.
Next up on the list was globular cluster M4 in Scorpius. M4 is only about one degree away from the bright star Antares. Although M4 is about magnitude 5.9 and has a size of 26.3 minutes, it always seems very dim to me. It is a large globular and is easily resolved. I think I just need better skies for this cluster.
The constellation of Vulpecula would present me with my next object, M27, known as the Dumbbell Nebula. This a big, bright nebula and I'm ashamed to admit that I haven't been observing it for years. Weighing in at a size of 15.2 arc minutes and a magnitude of 8.10, it is easily visible in any size scope. I have observed it with 10x50 binoculars. In my scope, the dumbbell shape was instantly recognizable, but not as prominent as you see in the photographs.
Next I "star hopped" over to M57, the Ring Nebula in Lyra. M57 looks like a ghostly smoke ring in the sky. It shines at magnitude 9 and has a size of 2.5 arc minutes. I have been able to locate M57 in all kinds of skies, from dark to moderately light polluted. While it shows up nicely in my 80mm refractor, I find that I need a larger scope (or darker skies) to see it as a ring.
My last object of the night was M13, the Great Globular Cluster in Hercules. At a magnitude of 5.7 and an angular size of about 10 arc minutes, this cluster is the king of globulars for northern observers. I'm never disappointed in how it fills the eyepiece with a multitude of stars. Since it is so bright, M13 holds up well to magnification. I love to zoom in until all I see are thousands of little pinpoints of light.
Since my optics were dewing up, I decided to call it a night (especially after my wife flicked on the porch light and ruined my dark adaptation). I took one last glance at Jupiter to note the progress of the shadow transit of Callisto. It definitely had moved from the central meridian onto the eastern portion of the planet. All in all, it was a pretty good observing session.
Jeffrey L. Polston
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