Telescope Astro-Physica 155EDFS (155mm f/7)
Friday
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
adds about 1.25 to the magnification of the eyepiecs.
It was a fun weekend even with a huge moon lighting up everything.
Clear skies,
Rich
Received on Mon Aug 30 03:15:55 2004