The Occultation of a W=10.0 Star by Asteroid 2001 UM23

Sun eve May 25, 2025 at 9:35:13pm

OWc page

 

This is a bright asteroid event, likely to be seen through cirrus clouds. It's just south of Moss Landing. Duration only 0.4s, but we should be able to do it at 1x.

Alt=34, az=231 in Sextans above Hydra.

 

 

Results:

Kirk and I, through mis-communication, ended up at the same site, shown on the map above and very near the centerline, and I did not know he was there until after the event! It was clear, despite the cloud forecast. We had significant wind which will affect our light curves. I'll probably want to use dynamic masks. We both got recordings. Unreduced at this point.

Richard Nolthenius

I had a lot of wind, tried the "batman" move during the critical moment, but still had a gust of wind come through right at event time. I used dynamic mask, and PyOTE found an event. which is, alas, noise. Kirk's record was not bothered by noise at the event, and clearly shows the target star on all frames - a miss. My effort will have to go down with a Purple Heart - killed in battle. I did take a few pix of the set up...

   

Kirk Bender

Got a miss. Hiding behind his car on shortened tripod legs, the wind gust that foiled me, didn't hurt Kirk.

 

 

 

Kirk Bender

No apparent event for 2001 UM23, 2x, on May 25, from Molera rd. in Castroville. There was a lot of wind shake, minimized as much as I could be shortening the tripod and keeping close to my car. I smoothed out most of the shake on the reference star, but still no sign of an event. PyOTE detectability tool reported an event as short as .15s would be detectable, predicted max was .4s.

RN: This looks like a clear miss to me, on his data. Strange; we were on the centerline and very high odds of a "hit".