by Richard Ozer
When Saturday falls on or near a full moon, I often pack up my 10" Dob and bring it up the hill to the Chabot Space and Science Center. A handfull of amateur astronomers gather there on a regular basis to help with the public program and do some non-serious observing. Most of the time the 8" Alvin Clark refractor, and the 20" Brashear are open to the public and offer mediocre views (because of the seeing...not the scopes) of the planets or other prominent objects.
My house is in the flats below the east bay hills and I noticed it was getting kind of chilly. I put on a couple of layers, packed up and drove to the observatory. I was surprised to find it much warmer up at the top, pretty much short sleeve weather that remained constant throughout the night.
At first, there was little to look at. M13 was in the murk to the west, Andromeda was entirely unimpressive due to the light pollution and rising moon, M15 was in Dobson's hole; so I turned the scope to eta-cassiopeia and talked about binary systems for a little while.
Ken Swaggerty, a talented scope maker who led the team that restored both the Clark and Brashear refractors, approached me about an object he had stumbled upon near Vega the night before. Ken described a deep ruby red star 1/2 Telrad's width away from Vega, directly across Vega from the Double Double. Sure enough there it was at, we estimated, Magnitude 7. It was incredibly red, redder than R Leporis or any other Crimson star that I've seen. We had no charts with us, but I later identified it as T-Lyrae, a C8-Carbon Star Variable that fluctuates between Magnitude 7.5 and 9.3. It's clearly at its maximum and deserves additional watching. Here are the particulars from 2 different sources. TheSky shows it as a C8 spectral class star:
SAO 67087 GSC 2636:1142, HIP 90883, B+36 3168Spectral C8 **** Data from Hipparcos Catalog **** Proper motion (mas/yr): RA = -6.17, Dec = -3.51 Distance: 2064.28 light-years, 130547576.63 astronomical units Magnitude: 7.57 RA: 18h 32m 20.076s Dec: +36°59'55.644" (Epoch 2000) Uranometria shows it as an irregular period R6 class. I don't know which is correct... you tell me...
T Lyr 18:32:20 36:59:58 7.5-9.3 Irr R6 I 117In any case, it's easy to find and definitely worth checking out. For a good list of Carbon Stars, go to http://www.jacksonville.net/~rcurry/carbon.html
By the time we finished with T Lyr, Saturn was rising. I turned my scope onto Saturn and was floored by the steadiness and detail of the image. I popped in my 4.8 mm eyepiece, bringing the magnification up to 300x or so and it held! This was the night I was waiting 2 years for. Last winter's gas giant viewing was so memorably poor, I thought I had cataracts. Last night, though, I had no trouble picking out the C ring and Enke's division. Cassini's division was visible at low power. I had actually had first time viewers seeing these details with no trouble at all.
Both the Alvin Clark and Brashear were trained on Saturn as well. Now I know why Alvin Clark scopes are so famous. It's not just because they're old and cool looking. That was, hands down, the best view of Saturn I've ever seen. It was cranked up to 350x and then 500x and was magnificent. The Brashear showed even more detail on the rings, but had a definite blueish tinge to the image which I found distracting. I much preferred the warmer colors on the Clark and, knowing next to nothing about refractors, am curious about which scope was more accurate in representing color.
Jupiter was too low to the horizon for my Dob to magnify beyond 150x. It showed nice detail, color, and all 4 major moons, with Io just beyond the limb. The Clark is elevated and in a nice dome. It held the image at 300x and showed beautiful detail.
I finished off with low magnification viewing of the moon. I've taken to using a standard polarizing filter as a "moon filter" on a 30mm eyepiece, and have enjoyed full moon viewing with this configuration. Having blinded myself and everyone else with moonbeams, it was time to pack up.
If last night was any indication, we may be in for a good month of Jupiter and Saturn viewing.