Callisto shadow, Venus crescent and moon pie

by Jane Houston Jones


We love to observe the third quarter moon and often set up our f/9 AP180EDT in the late evening, set the alarm, wake up when the moon is high overhead. Then we observe in the early morning stillness. Last night, November 27th was one such night. The clear sky clock indicated good seeing at our location at 37N 122W 15 miles north of the Golden Gate Bridge in the San Francisco Bay area. We looked up Jupiter events using Sky Map Pro 9 and discovered a Callisto shadow transit would begin at 3:09 a.m. local time.

We invited a friend over. Then we went to see an excellent movie - "Standing in the Shadows of Motown" - we highly recommend it! When we returned at midnight we set up the telescope, and had a look at Saturn. Our friend arrived at 2:00 a.m.and we all took turns observing Saturn. Don't you just love this hobby - inviting a friend over at 2:00 a.m.! Using Akkana Peck's Satmoons 0.7 for the Palm I had a a fast way to check which satellites I could see. Titan, Dione, Enceladas, Mimas, Tethys and Rhea were all visible and disk shaped through the big refractor. There were a couple bright stars in the field when I looked on Sky Map Pro on the laptop inside. It's nice to have a handy handheld Saturn tool like Satmoons to verify these things outside. I sketched the moons. That accomplished, I took a look at the rings and the planet. Soon the seeing deteriorated, but not before we had a pretty nice 6mm Radian (300x) view of our lovely ringed planet. We took a quickie view of the GRS on Jupiter, but the planet was still too low for good views. The GRS crossed the central meridian at about 1:24 a.m. according to Akkana's Jup 0.2. It was a pretty washed out view, so we decided to sleep for a couple hours and wake up at 5:00 a.m. for the Callisto shadow transit and for some moon views.

At 5:00 a.m. we stumbled outside, with warm coffee and cold toast. It was 51 degrees outside. The little shadow of Callisto began its transit at 3:08 a.m. (11:08 UT) and ended at 7:52 a.m. 15:52 UT, so it was well underway at 5:00 a. m. The moon Callisto is so far from Jupiter that its orbit is the slowest of the 4 Galillean satellites and the shadow transit goes on and on and on. Because the moon is so far from the planet it exaggerated the sun angle - it was fun to see Callisto's shadow on the planet while Callisto itself was visible two Jupiters away!

That was alot of fun, and the three of us were ready for some moon action. The cold had helped to wake us up too. It was now about 5:30 a.m. and the moon was in the trees. We switched from 6 and 10 Radians to the Zeiss Binoviewer and a pair of 25mm Zeiss Abbe Orthoscopic eyepieces + barlow for 200x. I spotted "Pinus" Iridum in the treetops of the Monterey Pine tree next door. Between branches we had great views of Sinus Iridum, Caroline Herschel and the much larger John Herschel using Rukl 2 and 10.

For the next hour or so we took turns observed Mare Orientale I have a sketch of the area on which I wrote all the lunar features to help my friend (and me) identify them. http://www.whiteoaks.com/sketches/mare_orientale.html We also opened the good book Rukl to pages 39and 50.

Next I was drawn to the ghost crater Kies and Bullialdus environs shown on Rukl 53. Rima Hesiodus was easily visible. My very favorite view however was a moon pie - the small crater Cichus on the southern side of Rupes Mercator and Rima Hesiodus shown on Rukl 63. Kies points to it, actually, but you have to flip between the two maps. This little crater looked like a Thanksgiving pie with one piece missing (or one piece left, depending on your point of view). The slice of pie was a little triangular wedge of light widest on the western side of the crater, pointing north-eastward towards Weiss. It wasn't a sunset ray (wrong direction for a ray) but whatever peak caught the light made a great view.

Before it got too light out, we took a look at the lovely crescent Venus through the telescope and Mars above it, and visually tracked the ecliptic all the way from sunrise to Saturn. We have a lot to be thankful for.