The Occultation of a W=12.0 Star for 1.4s by Asteroid Grieg

Feb 22, 2026 at 8:50:27pm

OWc page

This event should be much easier to find than most - it's a member of the bright star cluster NGC 2129 in Gemini.

Alt=72, Az=222, which means it is at higher altitude prior to the occultation.

20 min before the event the altitude is 75 degrees; too high, but if you wait till 8 minutes before the event before inserting the standard configuration, the altitude will be only 73 degrees and will fit OK. That'll be my plan.

My site: the parking lot on the west side of Hwy 1 at Lat 37 00 30.7" latitude.

Results:

Kirk and I drove separately, and both of us got clear positives; Kirk from just south of the centerline, me north of the centerline at Shark Fin Cove parking.

Richard Nolthenius

I set up at the Shark Fin Cove parking area, 35 ft north of the notch where the trail starts in the cliff side. There was wind, so I positioned my car to minimize its effect and it was not a serious problem. Observed at 2x. One gust of wind early on caused a drop in all stars very briefly. It was trimmed out in PyOTE before solving.

NIE test: 33.2 sigma
magDrop report: percentDrop: 92.3 magDrop: 2.787 +/- 0.634 (0.95 ci)

DNR: 2.67

D time: [04:50:24.1448]
D: 0.6800 containment intervals: {+/- 0.0122} seconds
D: 0.9500 containment intervals: {+/- 0.0343} seconds
D: 0.9973 containment intervals: {+/- 0.0767} seconds

R time: [04:50:25.6439]
R: 0.6800 containment intervals: {+/- 0.0122} seconds
R: 0.9500 containment intervals: {+/- 0.0343} seconds
R: 0.9973 containment intervals: {+/- 0.0767} seconds

Duration (R - D): 1.4991 seconds
Duration: 0.6800 containment intervals: {+/- 0.0177} seconds
Duration: 0.9500 containment intervals: {+/- 0.0418} seconds
Duration: 0.9973 containment intervals: {+/- 0.0846} seconds

brief wind gust near the beginning

The 1.49s occultation

Trimmed light curve in PyOTE

Zoomed in. Very good S/N and accurate timings on this one. Happened about 1s early.

33 sigma NIE test

Testing out my new fisheye lens. Nice!

Kirk Bender

I got a recording at 2x from the BD beach parking lot.  Looked like an event, on the order of a sec. The altitude wasn't a problem, the camera fit without the diagonal after the align and goto. That long parking lot was empty, then several cars of youngsters drove up and parked right next to me. They didn't bother me though, they just walked to a party on the beach I guess.I got a clear 1.5349 sec event for Greig, 2x at the Bonny Doon beach parking lot Feb. 22. There were scattered high clouds but it was clear in the target area.

PyOTE NIE sigma distance 36.2.
magDrop report: percentDrop: 94.0  magDrop: 3.058  +/- 0.771  (0.95 ci)

DNR: 2.73

D time: [04:50:24.0493]
D: 0.6800 containment intervals:  {+/- 0.0102} seconds
D: 0.9500 containment intervals:  {+/- 0.0280} seconds
D: 0.9973 containment intervals:  {+/- 0.0635} seconds

R time: [04:50:25.5842]
R: 0.6800 containment intervals:  {+/- 0.0102} seconds
R: 0.9500 containment intervals:  {+/- 0.0280} seconds
R: 0.9973 containment intervals:  {+/- 0.0635} seconds

Duration (R - D): 1.5349 seconds
Duration: 0.6800 containment intervals:  {+/- 0.0147} seconds
Duration: 0.9500 containment intervals:  {+/- 0.0347} seconds
Duration: 0.9973 containment intervals:  {+/- 0.0693} seconds

Karl von Ahnen