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433 Eros


 2012 Jan 5

Canon EOS 5D MkII ISO6400 37x8s
254mm Newtonian (2x Barlow, f=2400mm) f/9.6
HEQ5 equatorial mount, driven but not guided
2012 Jan 5 22:48:31-23:58:33 UT
From Rookhope 54.8N 2.1W 330m asl. Rural, almost no light pollution (3 Bortles)

8 second exposures were taken automatically at 2 minute intervals except at the start, where I was setting up. So the start of the trail looks uneven. The asteroid is moving southwards into Leo, this photo being near the border with Leo Minor. The asteroid appears fainter than the bright stars here because it is smeared out, whereas the stars are added 37 times.

The orientation of the photo is shown by the following diagram. The photo above occupies the light blue rectangle. (The diagram is from another Java program of mine called Hopper that I use for finding objects at the telescope.)

The 4 brightest stars marked in the diagram are identified in this table (from the Hipparcos/Tycho data sets).

LabelStar idRA (J2000)Dec (J2000)mv
ATyc 1427 731 110 35 11.79+21 17 13.510.57
BHip 5182610 35 17.32+21 22 43.57.78
CTyc 1427 884 110 36 26.28+21 27 03.010.11
DHip 5194210 36 41.01+21 36 11.48.71

Using that information in GRIP enabled me to calibrate the photo in pixels/degree from which the size of the (cropped) field was measured as 0.489 x 0.298 degrees. Eros moved 0.0430 degrees in the 70 minutes and 2 seconds of the sequence (faster than predicted at opposition because it is closer to us now).

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