This is a good rank event, bright, 0.4s long, should be a high probability evening event. I will already be on the east side of town, after doing a Flex activity near Cabrillo. Then make charts in my office, then a quick dinner at Los Gordos, then on to the centerline at San Andreas/Larkin Valley Rd.
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I emailed Kirk as well, and he was game to go to Moran Lake to try it just inside the northern limit.
I observed from the same spot I'd used once before, next to the fence of an open field on the north side of Hwy 1 at Larkin Valley Rd. Dark sky there, but the ground was wet, soggy, and deep with natural meadow grass. Not very stable vs what I am used to being able to enforce. No realistic short-time alternative. Sky was dark, though, and no wind, so in other ways the conditions were good. I was able to get this at 1x easily. It looked visually like it faded to half brightness for 0.5s, but not a full disappearance as was expected. Is this a binary star? I've not reduced it yet
Here's my first cut at this one. PyOTE did find an event at the correct time, after trimming out some bad tracking and bad seeing moment. But the NIE was only 1.4 sigma. And as it looked live, the event did not go to zero, but down only 60%. Double star? Graze? Kirk was decently inside the path but had a miss, indicating a south shift, so it could have been a short event and noisy. I used 1x but perhaps that was too noisy?
The GOOD NEWS, is that my OCR profile for Valda, still worked with no OCR errors for this event. This is the first time I've had OCR work on an event it was not trained on, since the Startech era began for me.
magDrop report: percentDrop: 60.8 magDrop: 1.018 +/- 0.476 (0.95 ci)
DNR: 2.21
D time: [03:20:59.3890]
D: 0.6800 containment intervals: {+/- 0.0184} seconds
D: 0.9500 containment intervals: {+/- 0.0817} seconds
D: 0.9973 containment intervals: {+/- 0.2205} seconds
R time: [03:20:59.5890]
R: 0.6800 containment intervals: {+/- 0.0184} seconds
R: 0.9500 containment intervals: {+/- 0.0817} seconds
R: 0.9973 containment intervals: {+/- 0.2205} seconds
Duration (R - D): 0.2000 seconds
Duration: 0.6800 containment intervals: {+/- 0.0310} seconds
Duration: 0.9500 containment intervals: {+/- 0.1071} seconds
Duration: 0.9973 containment intervals: {+/- 0.2653} seconds
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My second attempt, was to choose a better Track2 star, as the first track star hit the chip edge early and required trimming. The second track star did not do this. Still, the seeing was not great in this lower-altitude event, and the event was also short, only 0.20s. Worse, the site was on soggy thick meadow grass and I discovered that even minor movement could cause tracking error. I did expect some of this and so took great pains during the seconds before and after the event time, to be very still. The event was again detected by PyOTE, and the significance NIE was better, at 3.1 sigma. It happened precisely at the predicted time of 3:21:59.50, with the lowest point perhaps being the maximum occultation. Being so short, and noisy, the significance likely cannot be improved. I used the 2.4px size mask, as usually is best. There were a couple of periods of short wisps of aerosol (or more likely, tripod vibration on the soggy ground?) which show in each of the stars' light curves, but because of the noise, they could not be effectively removed and still minimize the metric, and instead I had to trim them out.
It's possible the star is a close double and I saw only the brighter component disappeared, but the data quality is not good enough to differentiate this from a 'graze' or very short event.
Kirk Bender's miss, from nearer the northern limit, together with mine, suggest a significant south shift and I got only a bit of the asteroid, not the 0.4s duration predicted. The two runs gave identical timings, but slightly better timing accuracies on the second run, and higher NIE test sigma results.
magDrop report: percentDrop: 59.4 magDrop: 0.979 +/- 0.398 (0.95 ci)
DNR: 2.23
D time: [03:20:59.3890]
D: 0.6800 containment intervals: {+/- 0.0172} seconds
D: 0.9500 containment intervals: {+/- 0.0659} seconds
D: 0.9973 containment intervals: {+/- 0.1799} seconds
R time: [03:20:59.5890]
R: 0.6800 containment intervals: {+/- 0.0172} seconds
R: 0.9500 containment intervals: {+/- 0.0659} seconds
R: 0.9973 containment intervals: {+/- 0.1799} seconds
Duration (R - D): 0.2000 seconds
Duration: 0.6800 containment intervals: {+/- 0.0282} seconds
Duration: 0.9500 containment intervals: {+/- 0.0875} seconds
Duration: 0.9973 containment intervals: {+/- 0.1986} seconds
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Looks like a miss for 1994 PC16, 1x at Moran lake. No apparent event. There is a single low point near predicted but there are similar low points throughout the target curve.
PyOTE detectability tool reports an event as short as 0.11s would likely be detectable, max predicted was 0.43s.
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