The Occultation of a W=11.2 Star for 0.6s by Asteroid 1999 XD40

Thur eve Jan 22, 2026 at 11:17:07pm

OWc page

 

This is a bright event, rank is only mediocre, but odds are decent if I drive to the east entrance to Wilder Ranch to set up on the centerline. Weather looks promising. Alt=23 Az=89 in Coma Berenices. I could probably get if from Rincon St, but odds of a "hit" are only 50% there.

Alt=23, Az=89 in Coma Berenices

     

 

Results:

Richard Nolthenius

I drove to the east side bike path entrance to Wilder Ranch for this event. Fog rolled in after set up, and I got no data.  Kirk Bender got lucky, and in the direction of the event, skies were clear.

Kirk Bender

I got a 0.6s  event for 1999 XD40, 2x on Westcliff drive on Jan. 12. Fortunately clouds didn't come in until after I recorded, and it wasn't windy on the cliffs.

NIE sigma distance 14.9
magDrop report: percentDrop: 96.1  magDrop: 3.517  +/- 2.402  (0.95 ci)

DNR: 2.46

D time: [07:17:06.3759]
D: 0.6800 containment intervals:  {+/- 0.0117} seconds
D: 0.9500 containment intervals:  {+/- 0.0340} seconds
D: 0.9973 containment intervals:  {+/- 0.0934} seconds

R time: [07:17:06.9765]
R: 0.6800 containment intervals:  {+/- 0.0117} seconds
R: 0.9500 containment intervals:  {+/- 0.0340} seconds
R: 0.9973 containment intervals:  {+/- 0.0934} seconds

Duration (R - D): 0.6006 seconds
Duration: 0.6800 containment intervals:  {+/- 0.0176} seconds
Duration: 0.9500 containment intervals:  {+/- 0.0440} seconds
Duration: 0.9973 containment intervals:  {+/- 0.1010} seconds