The Occultation of a R=9.9 Star by Asteroid 2000UY51

Mar 28, 2024 at 11:14:01pm

 

This is a bright event, nominally of high rank, through Scotts Valley, northern limit just south of Karl. Alt=41 Az=260 in the West. Weather is pretty sketchy, but anyway, we can hope.

It will be difficult for Karl to get inside the path from locally, given the slope of the path. Shortest idea is to drive down Old San Jose Rd to Amaya Ridge Rd and drive up that road until it opens up into a pasture area where he could probably set up w/o hassle at the spot I have on the OWcloud map

I've set myself just north of Scotts Valley town north of the high school, on a road that Will says is a good spot for astrophotography. I could carpool Kirk to another spot nearby. The rank is not perfect, but good enough to justify an attempt given how bright it is.

Odds at my icon are 74%, and my proposed Kirk site would be about 70%. It's 77% odds on the centerline. Karl's spot would also be in the 70's % area, but at home it's more like 17%.

Cloud cover at 11pm predicted in Scotts Valley to be about 30% clouds on the ECMWF prediction. I'd take those odds. It should be cloudier earlier in the evening though.

 

 

Results

Richard Nolthenius

I set up at the gravel parking area for horses on Canham Rd north of Scotts Valley off Glenwood Drive. Skies were mostly clear, but some thin cirrus was in some spots, drifting. It does not seem to have affected my recording. The star was brighter than I expected for R=9.9, and given the short predicted event, I felt we could get good data at 1/50s (field duration) and then process in field mode. The recording shows no occultation or hint of an occultation on any frame.

I did have an issue; this is a never-before used IOTA VTI v3, and the almanac for DeltaT had not yet been downloaded. That took about 15 or 20 minutes, and happened after the occultation. However, there is no discontinuity to the time from the "hourglass" time base shown on the light curve, and the non-hourglass moment which was at 6:18:00. I take that to mean that there was no new leap seconds inserted since the unit was made. That makes sense; we've not had a leap second for over 4 years.

Long 122 00 03.54

Lat 37 04 45.70

elev= 795ft