by Albert Highe
The temperature reached 101°F as I drove through the Central Valley toward Merced. It was 96°F when I pulled into Michelle's driveway at 4:20PM.
The temperature dropped quickly after sunset, reaching a low of 69°F and 40% RH at 12:30AM. That's when the clouds moved in from the South and covered the sky. Until then, the warm, dry, windless weather was ideal for observing in just a T-shirt. The clouds were unusual, especially since the humidity stayed so low. Seeing was relatively good, allowing magnification of 286X for the entire observing session.
Clouds passed through during the day. After sunset they quickly disappeared. Conditions were essentially identical to Thursday except that the clouds moved in a little earlier. I stopped observing after 11:30PM. A couple of hours later the skies were clear. However, I had already packed up by then.
As sunset approached, the afternoon clouds cleared. It looked like it was going to be a good night. However, after observing for a half an hour, and just as it started to get really dark, the clouds moved in again. Fortunately, all of us waited for the skies to clear. By 10:30PM, the skies were great, revealing the best transparency of the three nights. Seeing was also good. Clouds moved in and out periodically, starting again around 1PM. Even at 2PM, the temperature was 73°F with a relative humidity of 37%.
| Scope | 17.5" f/4.5 ultralight |
|---|---|
| Eyepiece | 7mm Nagler T6 (286X) |
Selected Notes and Observations
I thought Shingletown was my last opportunity this year to observe galaxies in Abell 1656, The Coma Cluster. I was wrong. I got less than an hour each day, just after nightfall, to tease a few more observations from this cluster. I found 25 new galaxies, bringing the total to 382. At least 41 of these galaxies are not gravitationally bound to the cluster. For more details, see http://pw2.netcom.com/~ahighe/a1656.htm.
(Observations of this group were made when it was approximately 50-55° above the horizon).
Approximately 1° NNE of NGC 7331 lies a small group of galaxies. Four of the brighter members, including UGC12127, lie at the corners of a small parallelogram. The sides measure approximately 2.4' X 1.3'.
Slightly oval, visible with direct vision, and noticeably the brightest.
These three galaxies lie at the other corners of the parallelogram, listed in clockwise order from UGC12127. On Saturday, I held each 100% of the time with averted vision. With direct vision they tended to disappear to varying degrees. MCG+6-49-56 was the easiest to see of the three, and appeared somewhat elongated. MCG+6-49-61 was the most difficult. MCG+6-49-60 was smaller and circular, with higher surface brightness. In contrast, on Thursday, I held MCG+6-49-61 with averted vision only 75% of the time.
This galaxy lies approximately 1.1' SE of MCG+6-49-60. It appeared small and circular. I held it with averted vision 90% of the time.
Just outside the NW border of the parallelogram lies an 11.5 magnitude star. Approximately 1/3 of the way from MCG+6-49-56 and this star lies MCG+6-49-57. This galaxy was very challenging. I had fleeting glimpses of it Thursday night. During the improved transparency Saturday night, I held it with averted vision 30% of the time. It is considerably smaller than MCG+6-49-56, 0.5' away.
This galaxy is easy to locate (although very challenging to see). It lies approximately 0.3' WNW of a very faint double star that is approximately 1.3 ' NE of MCG+6-49-61. As with MCG+6-49-57, I only had fleeting glimpses of it Thursday night. On Saturday, I held it with averted vision 25-30% of the time. I judged it was a bit dimmer than MCG+6-49-57.
Another example of the difference in transparency between Thursday and Saturday nights. The percentage of time I held with averted vision: Thursday 60%, Saturday 100%. Slightly elongated E-W.
There are a few brighter galaxies slightly farther away from the above closely spaced group.
5' east of PGC3088581. Oval visible 100% of the time with averted vision.
Another 6' further north. Very easy to locate 2' N of a 10th magnitude star. Slightly elongated core visible with direct vision. With averted vision, highly elongated halo appears.
6' west of the 10th magnitude star mentioned above. Bright condensed core easy to see with direct vision. With averted vision, nearly circular halo of this face-on spiral extends approximately 1' across.
In the opposite direction from NGC 7331 lies the famous Stephan's Quintet. I 've reported observations of this group before and I didn't see anything new to add. However, there are three faint galaxies nearby I had never searched for: NGC 7320A, 7320B, and 7320C. Although these galaxies share the same parent name as one of the members of the Quintet, their radial velocities indicate they are considerably more distant from us.
Approximately 12' SE of the Quintet and 2' SSW of a 10.5 magnitude star. Very small and second most difficult. I found it best to align off a set of fainter stars that defined the base of an isosceles triangle with the 10.5 magnitude star at the apex. The galaxy was spaced midway along the base. Held with averted vision 50% of the time.
18' east of the Quintet. Easy to find approximately 1' NW of an 11th magnitude star. This galaxy is the brightest of the three. Could hold 100% with averted vision, even with its proximity to the "bright" star.
Only 4' east of the Quintet, but very easy to overlook. It was, in fact, the most difficult of the three. I believe I glimpsed it Thursday night. On Saturday, I held it with averted vision 25-30% of the time.
The rest of the time I shared views of bright showpieces and looked through others' scopes.
Thanks again Michelle. You know how much I appreciate your generosity.
Posted on sf-bay-tac Jul 22, 2004 11:52:38 PT
Converted by report.pm 1.2 Jan 03, 2005 19:47:21 PT