The Occultation of a W=14.55 Star for 3.9s by Asteroid Theresaoei

Mon eve June 1, 2026 at 9:40:21pm

OWc page

 

This is mostly a favorable event: 3.9s duration, 43 degrees altitude due south, not far from an easy to ID galaxy, RUWE is good. Great time of night... only one problem: it's only 14.6 magnitude. It will take long integrations to get it. 32x? maybe even 64x? It will be valuable to find out, actually. There's a 97% moon low in the east which will add sky brightness. The sun is at -14 and should be only slightly brightening the background sky.

It's a good practice event for our newest occulter - Danika. I plan to set up on TreeTop Lane in western suburbs of Scotts Valley, up Graham Hill Rd near the centerline. Plan would be to pick her up at 8pm and head up to the site and practice procedures. Berhard is in good position for this one too, and his larger scope and CMOS camera may be a great choice. I'll be interested to see how his imaging compares to our 8bit images.

Alt=43, Az=183 in Virgo, not far from NGC 4939 an SBc spiral galaxy at V=11.3 magnitude

     

 

Results:

Richard Nolthenius

I will have to remember whether I even got out the door for this one. Mail says I didn't get to clear skies, I think I must have bailed due to fog.

Kirk Bender

PyOTE found a 1.06s event in my data for Theresaoei, 32x at Skypark. The target was on the edge of a cloud bank, and the curve is noisy but above background level although barely. The event PyOTE found was much shorter than the predicted 3.93s max, and was 2.5s later than predicted for my location, 04:40:15. Note the predicted shadow was moving fast according to the Occult map, 1km = 0.84s, the predicted time for Scotts Valley was 5 sec earlier than for Santa Cruz. If I were estimating the event duration from the graph, I would say it is probably longer, but 1.06s was what PyOTE found.

Kirk included graphs, not downloaded by me and posted yet...


NIE sigma distance = 8.0.
magDrop report: percentDrop: 100.0  (magDrop cannot be calculated because A is negative)

DNR: 2.61

D time: [04:40:17.0561]
D: 0.6800 containment intervals:  {+/- 0.0948} seconds
D: 0.9500 containment intervals:  {+/- 0.2524} seconds
D: 0.9973 containment intervals:  {+/- 0.5063} seconds

R time: [04:40:18.1238]
R: 0.6800 containment intervals:  {+/- 0.0948} seconds
R: 0.9500 containment intervals:  {+/- 0.2524} seconds
R: 0.9973 containment intervals:  {+/- 0.5063} seconds

Duration (R - D): 1.0677 seconds
Duration: 0.6800 containment intervals:  {+/- 0.1413} seconds
Duration: 0.9500 containment intervals:  {+/- 0.3248} seconds
Duration: 0.9973 containment intervals:  {+/- 0.5646} seconds