Comets, asteroids and galaxies, oh my!

Reports for 2019
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Astro Day Coordinator
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Comets, asteroids and galaxies, oh my!

Unread post by Pete »

Thursday, December 5, 2019

The forecast suggested a workable night. I’m ready by 17:30 but cloud doesn’t clear until 18:27 hours. Air is 37°F and breezy. Jeff from the fall class has joined me.

1620 Geographos is a 6 km sized Apollo now 17.7 magnitude and 1 AU distant. Apparent motion is 1.3’/hr and since it was discovered in 1951 the uncertainty level is 0. However the RMS residual is high at 0.62’. Seeing is horrible and images are blurred. Imaged from 18:35 – 18:52 at 2 min exposure, 2X2 binning, -15C cooling, 2 Hz guiding. Frames 1, 3 & 5 show dRA = +0.2’ and dDEC = 0. S/N varies from14/1 to 8/1 but FWHM is consistent at 4.4”.

Comet P/Wiseman-Skiff (114P) is 14.0 magnitude and 0.7 AU distant. Motion is 1’/hr Imaged from 19:06 – 19:18 at 3 min, 2X2, -15C, 2 Hz. Frames 1, 2 & 3 show dRA = +0.8’ and dDEC = +0.1’ S/N is 25/1 and FWHM 4.3”

Comet P/Blanpain (289P) is a dim 15.9 magnitude and low in the muck. Couldn’t hold the guide star due to excessive air turbulence and wisps of cloud to the NW.

NGC 925 is a 10th magnitude barred spiral galaxy 30 million LY distant. Imaging initiated at 19:41 – 3 min, 1X1 binning, -15C, 1 Hz guiding. Captured only 5 frames before cloud shut us down.


I'm starting to suspect that my "bloated" stars are associated with the absence of an IR filter (which would significantly reduce sensitivity needed for astrometry).

In at 20:16 hrs. It’s now 32°F. 6 observations forwarded to the Minor Planet Center.

p.s. Viewing this image on a 19" monitor from a distance of 20", just calculated the magnification to be 94X. Always wondered 'bout that.
Pete P.
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