The last few nights have been wonderful. We've had a record heat wave during the daytime but the nights have cooled off into the low 80's and with a light breeze and low humidity have been wonderful for viewing. Last night the milky way was gorgeous, and again tonight. I decided to try for Vesta since it is near opposition and bright. Capricorn was up nicely in the SE although it took a lot of back and forth with my pocket sky atlas and 7x50 binoculars to convince myself it was really Capricorn. By midnight, my eyes had become dark adapted enough to clearly make out the bat-wing shape of Capricornus without binoculars. Earlier, I had updated my asteroid elements and had plotted the position of Vesta with Ciel. Armed with that information and my pocket sky atlas I began to look for something that wasn't supposed to be there. Right now, the stars from Zet and 34 Cap to Eta Cap form a kind of upside down ice cream cone, with a single scoop formed from 33 and 35 on one side with three non-descript stars on the other. The apex of the cone is Zet Cap with one side formed by 27 and Phi Cap, and the other by Chi Cap and Vesta. The clincher was a small group of 4 stars in the atlas that look like an L, 7, or a checkmark. These are all mag 7 with no mag 5 or 6 stars nearby. Bright Vesta is right next to the middle star of the leg of the L (SAO190147), a mag 7 star that stands out nicely from brighter Vesta.
Vesta is the brightest asteroid and large with a diameter of 330 miles. The Dawn spacecraft began orbiting Vesta on July 16, 2011 and is sending back images. It will continue taking data around Vesta until July 2012 when it will leave orbit and head for the dwarf planet Ceres.
Friday, July 29, 2011
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