Object name: 2003DZ15

Designation(s): 2003DZ15,

2003DZ15 made a "close" pass by the Earth at the end of July 2013. That is, if you consider 2.1 million miles close. Unfortunately, it was cloudy that and the following night. The weather was poor the night before but I did manage to get 20 two minute frames through a semi-gap in the clouds. The asteroid was 90,000 miles further away but slightly brighter due to it moving toward the sun so we were seeing less of its sunlit side each night. The difference was only a tenth of a magnitude. When dealing with a 17th magnitude object that's not all that great a difference. Thanks to the clouds and haze between clouds it appears even fainter in my movie.

I used some rather harsh processing to try and make the star trails look rather even. In the raw data, they varied greatly in intensity as the obscuring clouds changed their brightness rather rapidly. I first normalized on the asteroid to keep it rather constant then selected the star trails for repair efforts. Only the brighter were worked on so the faint trails have lots of breaks. Fortunately, they go by fast enough my eyes don't notice this unless I stop on a frame. The asteroid was moving at 46.9 seconds of arc per minute. This, however, did change by about a half second of arc per minute during the 40 minute run. Since The Sky only tells the mount the orbital motion offset at the start of the run and that started about ten minutes before I began the movie run as I was waiting for clouds to clear, the asteroid does drift slightly during the movie. Note that south is up in this movie rather than my normal north up. The movie seemed more "natural" that way.

While it was taken at 1.5" (binned 3x3) per pixel I've reduced it to 3" per pixel for the movie to keep the file size reasonable. Though you can run it full screen and get a better view. It survives this enlargement surprisingly well thanks to the lack of any detail to be resolved. You might want to set your viewer to auto-repeat as it runs 40 minutes of time in 4 seconds.

14" LX200R @ f/10, 20x2'x3, STL-11000XM, Paramount ME

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