3 september 2020

Three weeks ago there was a lightning storm than moved through the Bay Area in the early morning. It was fun to watch, with bright forking bolts streaming across the sky and loud thunder rolls. But, it started hundreds of fires, some of which combined into large fires on Mt. Hamilton, the Santa Cruz mountains, and around Lake Berryessa. The Mt. Hamilton fire nearly consumed the Lick Observatory, but it was saved. For us in the valley the problem was the smoke, which for most days was like a fog. We stayed indoors and tried to make due with idleness. There were some times when the air at ground level was relatively clear, and we could go in the back yard to shoot baskets or play with the neighborhood cat, but there was always a persistent smog in the sky, so astronomy was impossible. I could see Jupiter naked eye but I could not see Saturn. I worked on a taller central column for the CI-700 mount. The air started to clear Wednesday night, but the marine layer moved in by 9pm. Last night the air was clear enough to breathe but there was still some extinction, but it was good enough to get out for a session.

The taller column is about 6-inches too tall, but I plan to use it anyway. I need to stand on a ladder to reach the eyepiece for low altitude objects like the planets. Seeing was middling but the view was good at 140x. I looked at Jupiter and then Saturn -- there was a deep black shadow of the planet falling on the ring. Contrast is very good. I then pointed up to Altair to begin star hopping for various doubles, which I do by moving the hand controller -- a bit slow, but it works. Toward 11pm the marine layer was moving in so I had a look at the moon, just past full, and really pleased with the view.

Here are the doubles observed:

STF 2570 AB-C: 152; 285x: Easily split, white A and much fainter ruddy B. [Did not see AB, which is near equal mag. 0.2", which I could get with the 20-inch on a good night.
19H 44M 56.78S +10° 46' 30.6" P.A. 277 SEP 4.3 MAG 7.62,9.81 SP B3IV-V DIST. 170.94 PC (557.61 L.Y.)

STF 2583 AB: 152; 285x: Pi Aql. Very pretty near equal light blue stars, cleanly separated

19H 48M 42.05S +11° 48' 57.3" P.A. 106 SEP 1.4 MAG 6.34,6.75 SP A3V+F9III DIST. 157.73 PC (514.52 L.Y.)

BU 266 AB: 152; 285x: Pale white star with with a wide, much fainter ~4 delta mag blue companion

19H 57M 56.15S +11° 24' 53.0" P.A. 166 SEP 15.8 MAG 7.57,11.50 SP A3 DIST. 198.41 PC (647.21 L.Y.)

STF 2613 AB: 152; 285x: White, ~1 delta mag, nice wide split.

20H 01M 26.66S +10° 44' 54.8" P.A. 352.1 SEP 4.14 MAG 7.48,8.02 SP F5V+F5V DIST. 80.58 PC (262.85 L.Y.)

BU 488 AB: 152; 456x: Suspect elongation at 285x, notched and possibly split at 456x at best moments, noticeable magnitude difference. [Solar type double with F giant.]

20H 06M 43.37S +12° 56' 12.1" P.A. 356 SEP 0.8 MAG 7.55,9.13 SP F4III

STF 2664 AB: 152; 285x: Wide, white, slight magnitude difference.

20H 19M 38.48S +13° 00' 17.2" P.A. 321 SEP 27.1 MAG 8.07,8.34 SP K0 DIST. 409.84 PC (1336.9 L.Y.)

STF 2665 A-BC: 152; 285x: Wide, white, near equal, one of these has a close faint blue pair

20H 19M 21.16S +14° 22' 14.6" P.A. 12 SEP 3.3 MAG 6.88,9.55 SP KIII+BV+ DIST. 167.79 PC (547.33 L.Y.)

STF 2727 AB 152; 285x: Gam 2 Del. ! Most beautiful light orange-yellow A and ~1 delta mag blue-green B. 

20H 46M 39.50S +16° 07' 27.4" P.A. 264.8 SEP 8.9 MAG 4.36,5.03 SP K1IV+F7V DIST. 38.73 PC (126.34 L.Y.)

STF 2725 AB: 152; 285x: OR Del. Near equal, pale orange A and blue B

20H 46M 13.31S +15° 54' 26.4" P.A. 11.9 SEP 6.16 MAG 7.54,8.20 SP K0 DIST. 36.46 PC (118.93 L.Y.)

I tried Beta Delphinus since it was marked on the atlas as double, and there were some fainter stars about which might fit.  Looking it up today there is BU 151 which is 4.11/5.02 0.2" -- doable in the 20-inch but not with 6-inch.  Burnham discovered it with his 6-inch but it was 0.7" at the time.  It's great to have such a fine telescope to use for planets and such, especially when seeing is poor, but it's even better to have a 20-inch at my disposal to go after very difficult pairs.