by Rich Neuschaefer
| Telescope | Astro-Physics 155EDFS (155mm f/7 APO three element refractor) |
|---|
James Turley and I were the two lone volunteers with telescopes at Lick to support the concert and observing program for the public.
The sky was clear and dry, little wind and we had a temperture inversion making for shirt sleeve temps in the low 70s F. This was true for both Friday and Saturday.
The seeing was very good on Friday and even better on Saturday.
Friday the moon was very large. Crater Aristarchus was well out in the sunlight. I spent most of the night showing Schroters Valley using a 5.2mm Pentax SMC-XL giving about 208x. I did show some DSOs like M22 and M13 but they were not very pretty with such a bright background.
Near 1 am a visitor wanted very much to see something from a super nova. I mentioned to her that the Veil Nebula was up but it would be very hard to see. I tried it and found with the 2" OIII filter attached to the front of my Maxbright diagonal the contrast was much better than when the filter was attached to the end of the eyepiece (TV 27mm Panoptic). Putting the filter at the front of the diagonal greatly reduced the reflections coming back from the quite reflective OIII filter. We could see the bright arc of the Veil if we cupped our hands around the eyepiece to block out the moon light.
Schroters Valley (Rukl #18) looked very nice. We were busy and I didn't take much time to look at Rukl and try to see other smaller features.
Saturday, we had more help out back. A few other volunteers brought telescopes. We also had at least 150 visitors.
Toward midnight most of the visitors had left and I took the time go over the Rulk charts for small lunar features. The seeing was outstanding. Even though the terminator was a little farther past the thin rill rimma Marius I gave it a try and was very happy to see a thin wavy line that was a little lighter than the rest of the mare. The rill extended from a little beyond Marius crater P, moving down (south) toward Marius C and then away from Marius C. At Marius P, the rill is only 500 m wide (per Rukl page 62 and chart #8).
Near Marius C the rill is about 2 km wide.
We also saw a line that looked like a rill but is a crater chain (per Rukl page 60, chart 17). This Catena (crater chain) "connects" the craters Krafft and Cardanus.
I first saw the rill Rimma Marius using a 5.2mm Pentax SMC-XL eyepiece giving about 208x. Interestingly, a light blue 82a filter seemed to help the contrast. Later I used a 6mm Zeiss Abbe Ortho. It gave a very nice sharp, hight contrast view of the rill. Several other observers also saw Rimma Marius. When I realized we would be viewing that area of the moon for an extended time I switched to my Zeiss binoviewer and the 6mm Zeiss Abbe Orthos. This combo gave about 226x. The binoviewer mutliplies the magnification of the eyepiece/telescope combo by 1.25. The Zeiss binoview has a 1.25x Glass Path Corrector designed by Roland Christen to improve the image when using the binocular viewer.
It was a fun weekend even with a huge moon lighting up everything.
Posted on sf-bay-tac Aug 30, 2004 03:15:57 PT
Converted by report.pm 1.2 Jan 09, 2005 08:36:41 PT