The centerline goes close to Santa Cruz, and hopefully the fog will not come in till after the 12:39am event. The target is in northern Sagittarrius making roughly a flat equilateral triangle with Jupiter and Saturn. The event lasts up to 6 seconds, but is only 0.2 mag in depth, as the target is only 13.3 magnitude and the asteroid 11.7. I'll have to use more integration than just to see the target. Anothe problem is that the target is just 6 degrees straight above the nearly full moon.
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I'd hoped to get this from outside my place, but fog started to roll in 1 hr before the event, so I got the gear into car and drove up to Mtn Charlie Monument at the top of Hwy 17/Summit Rd where I had clear skies. The sky was too bright for x16, almost pure white from the full moon. And x8 was very bright too, so I backed off to x4 or 1/15 second per integration. That's 75 integration points per full 5 second occultation. On LiMovie I used the "lunar limb" option to avoid the 12th magnitude star close to the right of the target star. I linked tracking because if I left it on 'drift' for the target, at the time of the occultation it would lose the target. I opened up the inner aperature to 7 pixels so that the asteroid+star remained inside the circle for a minute before to a minute after the event, since it was the moving asteroid which made for most of the light. I believe it's the best quality data possible with this situation. In the future, I'll not bother with trying to get a 13th magnitude occultation at 4x integration only 6 degrees from the full moon. S/N was near zero! The .csv files are on my computer, but not uploaded to the server.
LiMovie screen. Target is near center, and I used the same bright (but not saturated) star as tracking and comparison star. |
LiMovie lightcurve, no integrations. raw. The red dot shows the predicted time of occultation, and a maximum duration occultation would be 80 frames wide, centered on the red dot, says the predictions. I don't see an event, although a dip of 0.24 magnitude might be missed if it was short, like only a second or so. |
Next I analyzed the csv file from LiMovie with Occular 4.02. But it failed to find an occultation with any confidence. The best candidate was 4.7 seconds after the prediction, centered on frame #1972 - which is within the possibility of an error given the confidence levels, but not that likely, and it's just not confident enough to claim as an event. |
