The Occultation of a Combined 13.2 by Adelinda

Tue June 16, 2020 at 10:23pm

Preston Predictions

Global map

 

A "sure thing", wide path and Santa Cruz is near the center, 100% odds of a 'hit'. However, the star is only 14.5 magnitude and will need long integration for the 0.4 magnitude dip of 8.4 seconds. 18 degrees altitude in SE and planned site is to go up to the Gray Whale Ranch bike trail crossing at the UCSC Upper Meadow.

     

Results

I had to use 64x integration to see the star well and try to get the shallow 0.4 magnitude dip. I figured I could get away with this if the occultation was roughly central and I had more than 5 seconds of integration. I was mostly right; the dip is visible in the light curve. However, it doesn't have enough points for PyOTE to declare the odds of a definite occultation were 0.9999 and so PyOTE would not give a solution. Instead, I used a smoothed version of the comparison star and did the subtraction and found the occultation looked a little more solid, but still no PyOTE solution. The smoothing in PyOTE will only be done if you use a smoothing over 5 points, no less than 5 points. That's way too much when here, this means 5 seconds. So I instead did the smoothing on the un-integrated light curve and that's what gave a better looking light curve as it let a point by integrated point target-comparison light curve to be generated. After some debating with Tony George on the wisdom of filing a report. I filed one anyway and the time actually agreed well with positive events from Tony himself and another observer, so in the end, it was added to the OCCULT solution despite the marginal statistical confirmation. Since PyOTE does not do Bayesian statistics on the probability the event was real (it agreed well with the other two obervers), and the probabily of a false positive is insisted to be extremely low (0.0001), then PyOTE gives no solution. Myself, I think PyOTE should report a best estimate of the D and R even if the odds it is a real event is only 99%, not 99.99%. What to do with the timings is always still up to the people.

OCCULT sky plane results