by Shneor Sherman
The wind had died down to a dead calm by now, and I'd say limiting magnitude was about 6.5, judging by the Little Dipper. Seeking a familiar object to check the 11 mm, we viewed Hickson 68 (althought most of the clouds vanished at dusk, there remained a band low to the horizon in the west). I had a quick view of M57 and a few more Ms in Sagittarius and then spent the next hour or so fruitlessly seeking Abell 2151.
By this time, Pegasus was well up in the sky, so we had first a nice view of NGC7331, very good even at 750x, with detail seen in the nucleus and a clear spiral structure. A couple of the companion galaxies were easily visible. From there, we moved to Stephan's Quintet, a pretty view at 375x. Then a group in the opposite direction from Stephan's, a bit fainter, ofur or 5 galaxies visible.
By this time, Gregg could hardly stand, and went off to sleep. I returned to Sagittaius, viewing using the binoviewer with the 11 mm on one side and an 18mm Widescan in the other, just to compare the view on a number of mostly beight nebulae and globulars. I also had nice binoviews of a number of objects, notably the Helix and the Veil. Byu this time Perseus was up and I had some excellent views of the Perseus cluster, usi a number of different eyepieces.
It was now about 1:30, ant the sky suddenly had many more clouds. I had about a half-hour nap, then enjoyed some rather nice view of Mars. But the seeing had deteriorated a bit and I could'nt get a good image over 375x. Nevethelesz, quite a bit of detail was visible - a dark border to the white south pole, and below that, a long, vertically-oriented (more or less) narrow triangluar dark area.
Now I noticed that Orion had risen, so I had a look at M42 (I think this must be the earliest first-of-the-season view of M42 that I've had). The 11 mm dis show all 4 stars in the Trapezium, though M42 was hardly above the horizon. It was nearly 3 by now, and the clouds had again spread over the sky, so I went to sleep.
The 11 mm has a listed AFOV of 80 degrees, and is "fully multicoated with blackened lens edges" - and is supposed to have been designed by Thomas Back. On Venus, it exhibited significant chromatic aberration eveywhere except dead center, but showed none on Mars. When used in my f/4, sherical aberration and coma combined to make a less than pleasing image. In the binoviewer, however (effectively f/5) it did not exhibit these negative traits, but had pretty good contrast but was not quite as bright or as sharp as I would expect (compated to a 9mm Orion Expanse). Still, it has a nice field of view for a binoviewer.
Seeing was outstanding for most of the night, and transparency was very good until the clouds arrived - and even then, those parts of the sky onobscured had good transparency.
CAS predicted poor conditions, but Weather Underground predicted clear skies, except for some cloudiness (the clouds low to the west). This time, the US model was more accurate.
Posted on tac-sac Sep 04, 2005 23:13:08 PT
Converted by report.pm 1.2 Mar 10, 2006 21:40:59 PT