The Occultation by Asteroid (261) Prymno

Oct 20, 2015

12.5 star occulted by Prymno, drop 1.8 magnitudes, duration 1.5 seconds, at 11:29:54 UT which is 4:30am local time. 33 degrees up in due east direction. Late new but controversial astrometry moved the path from SF down to Santa Cruz. Here's a hurried set of charts...

 

 

I drove down to the Observatory, set up the 10" scope and recorded a miss, using the Watec 910hx at 8x frames (1/4 sec time resolution). Packed up quickly, drove home and got back to sleep!

Image in LiMovie. Target is in center, and comparison star is upper left (purple in light curve at right). Saved .avi file ran from 11:29:19 to 11:30:19, but this was cut on the early side just to focus on the part that might have the event. Start time was 11:28:30 for the raw video.

8x frames gives groups of 8 dots which are at similar levels, differeing only in the photometry scatter. It's not high time resolution (1/4 second) for an event only supposed to last 1.5 seconds total, but there's no hint of a drop anywhere near the occultation time.

Here's the IOTA report, filed on Nov 20, 2015

 

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