The Occultation of a 9.0 Star by Asteroid (11277) Ballard

July 14, 2025 at 11:39:01pm

OWc page

 

A star this bright must be integrated at 1x, and even then it's wise to dial down the Gain setting. Karl's inside the path, and the road to Loma Prieta is also good. Mtn Charlie Monument is about the same track as Karl's place .

Alt=43, Az=90, in the "hooves of Pegasus" (ie upper right in the constellation).

     

Results:

I drove Kirk and myself up to the Summit area on Hwy 17. I set Kirk at the tree farm across from Garth's place, and I continued down to Holy City and it's wide pull out. Karl observed from home

Richard Nolthenius

I used the Startech, successfully. Set up in the wide turnout 125 ft west of Holy City Rd along Old Santa Cruz Hwy. Clear dry skies and no wind, moon rising. I used 1x, and Gain=40. Seeing was very steady. I saw no event. but I have not reduced the recording yet. It looks extremely likely I'll have a miss since Kirk had a confirmed miss, and Karl, south of Kirk, had a solid positive.

Very good data on this bright star. I used a dynamic mask, was happy to see how low the noise was in the star photometry. However, there were saturated pixels, even at 1x. No event, a clear miss.

 

         

Kirk Bender

Visually, saw a miss. Confirmed on exam of recording.

         

 

Karl von Ahnen

July 14 (15) 11:39:01 (11277) Ballard  from S of rock; Clear, no wind, moonless, steady seeing; 1/60sec, Gain=30, Gamma=60; very fast distinct blink.  Processing: used “field mode”, Target and Ref1 showed saturation, Event was very obvious in light curve.

magDrop report: percentDrop: 95.0  magDrop: 3.258  +/- 0.641  (0.95 ci)

DNR: 8.11

D time: [06:39:01.0522]
D: 0.6800 containment intervals:  {+/- 0.0017} seconds
D: 0.9500 containment intervals:  {+/- 0.0037} seconds
D: 0.9973 containment intervals:  {+/- 0.0072} seconds

R time: [06:39:01.3793]
R: 0.6800 containment intervals:  {+/- 0.0017} seconds
R: 0.9500 containment intervals:  {+/- 0.0037} seconds
R: 0.9973 containment intervals:  {+/- 0.0072} seconds

Duration (R - D): 0.3270 seconds
Duration: 0.6800 containment intervals:  {+/- 0.0024} seconds
Duration: 0.9500 containment intervals:  {+/- 0.0052} seconds
Duration: 0.9973 containment intervals:  {+/- 0.0093} seconds