A short cold night of observing

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A short cold night of observing

Unread post by Pete »

Wednesday, December 18, 2013

Tonight’s forecast was for a rapid diminishing of transparency, but at dinnertime the stars are undiminished! Quickly throwing together a few targets I’m opening the dome around 17:45. The air temp is 25°F and I’m feeling cold without my coverall – even with the heated sweatshirt.
The full moon is very low in the East and not yet a factor.

2013 XX8 is a little 95 meter sized Amor discovered 5 days ago. It’s only 5 million miles distant and 19.4 magnitude. Ephemeris uncertainty level is 7. Apparent motion is 2.4’/hr. Imaged from 18:43 – 19:18 at 2 min, 2X2 binning, -30C cooling, 10 Hz guiding. There’s a technical glitch involved – while XX8 is on the MPC’s short “critical object list” it’s missing from the “all objects” database. Had to go back & forth working from both lists. Using Astrometrica’s track & stack capability, frames 1-4, 5-8 & 9-12 show dRA = -0.1’ and dDEC = 0.0’ S/N ranges from 5.5 to 6.6 and FWHM from 4.1 to a tight 3.6 so these are quality measurements.

44862 is an 8.3 km sized main belt asteroid slowly moving through the 2013 XX8 FOV at 31”/hr. Tonight it’s 18.2 magnitude and 1.6 AU distant. The RMS residual is 0.56”. Frames 1, 8 & 15 show dRA & dDEC = 0.0’

377097 is a 757 meter sized potentially hazardous Apollo now .22 AU distant and 18.2 magnitude. Motion is 2.22’/hr, uncertainty level is 1, and RMS residual is 0.54” Imaged from 19:28 – 19:46 hrs at 2 min, 2X2, -30C, 2 Hz. Frames 1, 3 & 5 show dRA = +0.1’ and dDEC = 0.0’

Unable to find the other target data sheet, having the full moon high enough in the East to wipe out that viewing quadrant, and erroneously believing that I’d spotted cloud coming in from the west I shut down a bit prematurely at 20:00 hrs. Air temp was 24°F. 9 observations were subsequently emailed to the MPC.

Because of a failure to dress warmly enough most of the work tonight was done from inside the house using Windows Remote. Although viewing was brief tonight’s results detected drift from ephemeris and were worth the effort.

hgp 20:30 hrs, 18 Dec 2013
Pete P.