The Siwa Occultation

Oct 1/2, 2009

My second attempt with this asteroid in just over a month. This time the path went nominally through the center of Monterey Bay. Combined magnitude of 10.7 and a 1.1 mag drop. Again, the full moon was about 40 degrees east of the target but again that was not a significant problem. Cabrillo Observatory was well inside the predicted path, but because Derek Breit was not mobile and his backyard scope was essentially at the same track as Cabrillo, I decided to drive south. Initially I was going to go to San Juan Bautista and have dinner there before going out to observe, but I ran out of time and instead was headed to Aromas. Then, time got shorter still and I just headed south on Hwy 1 and planned to set up on an agricultural dirt road somewhere. As I arrived in Moss Landing, I suddenly realized I'd FORGOTTEN to load in the batteries when I was packing at Cabrillo Observatory. Doh! I instantly turned around intending to drive back to Cabrillo - but then realized I in fact had a backup set of wiring which could draw off the car's battery, so pulled over on the first dirt road I found, was able to find the star and get it taped with a few minutes to spare.

The star was focused, steady, and bright on my camcorder LCD screen. At 4:16:23+-3 seconds I thought I saw a blink which lasted about 1/4 or 1/3 second. My coordinates were: track 18.5N

long: 121 46.24'

Lat: 36 50.64'

Elev 160ft

Derek Breit had a 0.7 second occultation at 4:16:19.0, and says he saw the star in the central 2 frames, which would make it a graze.

Unfortunately, when I tried to play the tape back, I got the message "dirty tape heads. Clean heads!". I did so, but on playback the tape had blank bars crossing the frame, right across the target star. So I've got no record, only my memory.

Here's the profile from the observations