This is a bright, high, easy and long duration event. However, it's just 56 minutes after my Astro 3-2 class ends. That does give me time to drive deeper into the path, but I plan to get it from Cabrillo if the fog holds off; I will set up right outside the 806 Classroom and make this a special event for extra credit students to watch how science is done. The duration on centerline is 7.2s, so even at the boundaries it ought to be a second or more, which for that brightness of star, is an easy confident event. HOWEVER, the star position is not iron-clad. with a RUWE of 1.55. So I'd give my odds of a hit at Cabrillo at only 55%.
BUT, the event happens only 15 degrees from the 100% full moon. Sky brightness will be an issue. However, for 1x or 2x recording, it should not be a killer.
Alt=40, Az=133 in Pisces, 15 degrees due right of the moon, and about 0.75 degrees below Neptune
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This was a wide path, and many other observers, including Pranvera Hyseni. All of our team except Sandy got recordings.
I planned to make an extgra credit session for my students with this event outside the STEM Building room 806 classroom. But fog rolled in early and it was hopeless. So at the 9pm closing of the class, I drove as fast as I could back to Santa Cruz and up High Street and Empire Grade, arriving at Twin Gates where I saw no other occulters occupying it, and so I took advantage. I was able to set up quickly and got on target without trouble. Just barely above the fog, which had risen to Cave Gulch. I got a ~7s occultation at 1x.
I analyzed in frame mode, despite recording at 1x. So there's probably better timing accuracy to be recovered by a 2nd analysis, which I did later and is shown below this first analysis...
I was 2.2 km cross track south of Bernard's chord. The path width on the map is 120km, the listed diameter of Croatia is 88 km. 88km projecting onto the Earth at 120 km is reasonable. Now, .036 sec / 7s = .005 of the 120km cross track diameter = 0.6 km. So, assuming the likely diameter of the moonlet was not much more than the 0.036 sec inferred diameter, that would put the cross track shadow about 0.7 km wide. I was closest to Bernard's track, but I was 2.20 km south of Bernard's track , or 3x the inferred likely diameter of his moonlet. This says that none of our tracks provide a meaningful constraint or confirmation of his possible moonlet.
magDrop report: percentDrop: 92.6 magDrop: 2.833 +/- 0.210 (0.95 ci)
DNR: 4.25
D time: [04:56:55.3804]
D: 0.6800 containment intervals: {+/- 0.0072} seconds
D: 0.9500 containment intervals: {+/- 0.0177} seconds
D: 0.9973 containment intervals: {+/- 0.0362} seconds
R time: [04:57:01.7595]
R: 0.6800 containment intervals: {+/- 0.0072} seconds
R: 0.9500 containment intervals: {+/- 0.0177} seconds
R: 0.9973 containment intervals: {+/- 0.0362} seconds
Duration (R - D): 6.3791 seconds
Duration: 0.6800 containment intervals: {+/- 0.0104} seconds
Duration: 0.9500 containment intervals: {+/- 0.0231} seconds
Duration: 0.9973 containment intervals: {+/- 0.0416} seconds
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This time using "analyze in field mode", and also catching the "scope bump" quicker and recovering more light curve. The timing accuracies are improved, despite the fact the light curve has more scatter and so DNR is reduced to 2.96 from 4.25. That's expected, since there's 1/4 the light (1/2 due to integration, and 1/2 due to cutting the pixels counted in half) per integration. NIE confidence = 99.1 sigma.
Timing accuracies improved by about 10-20% for 1, 2 sigma limits. 3-sigma limits on accuracy were worse, but not a lot - to be expected if the point-to-point range is larger given it's 1x and only even or odd lines counted..
magDrop report: percentDrop: 90.9 magDrop: 2.598 +/- 0.194 (0.95 ci)
DNR: 2.96
D time: [04:56:55.3896]
D: 0.6800 containment intervals: {+/- 0.0059} seconds
D: 0.9500 containment intervals: {+/- 0.0160} seconds
D: 0.9973 containment intervals: {+/- 0.0424} seconds
R time: [04:57:01.7588]
R: 0.6800 containment intervals: {+/- 0.0059} seconds
R: 0.9500 containment intervals: {+/- 0.0160} seconds
R: 0.9973 containment intervals: {+/- 0.0424} seconds
Duration (R - D): 6.3692 seconds
Duration: 0.6800 containment intervals: {+/- 0.0086} seconds
Duration: 0.9500 containment intervals: {+/- 0.0205} seconds
Duration: 0.9973 containment intervals: {+/- 0.0476} seconds
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I got a 6.5829s event for Croatia, 1x at the BD eco reserve. I don't see any secondary events. NIE sigma of 84.7!
magDrop report: percentDrop: 86.0 magDrop: 2.135 +/- 0.145 (0.95 ci)
DNR: 3.43
D time: [04:56:55.2384]
D: 0.6800 containment intervals: {+/- 0.0049} seconds
D: 0.9500 containment intervals: {+/- 0.0135} seconds
D: 0.9973 containment intervals: {+/- 0.0383} seconds
R time: [04:57:01.8213]
R: 0.6800 containment intervals: {+/- 0.0049} seconds
R: 0.9500 containment intervals: {+/- 0.0135} seconds
R: 0.9973 containment intervals: {+/- 0.0383} seconds
Duration (R - D): 6.5829 seconds
Duration: 0.6800 containment intervals: {+/- 0.0076} seconds
Duration: 0.9500 containment intervals: {+/- 0.0180} seconds
Duration: 0.9973 containment intervals: {+/- 0.0473} seconds
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Duration: 0.9973 containment intervals: {+/- 0.1298} seconds
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Observed from the "red realty" place on Hwy 17 south of Summit Rd/Hwy 17. The closest chord was mine, north of him but this possible secondary event was only 0.0359 seconds which is 1/200th of the primary body, and so anyone more than 1/200th of the spacing of the shadow path would be likely to have not seen this event. None of our chords were at all close enough to confirm this event. PyOTE found the event easily, with these timings.
magDrop report: percentDrop: 83.6 magDrop: 1.965 +/- 1.664 (0.95 ci)
DNR: 3.69
D time: [04:56:38.0642]
D: 0.6800 containment intervals: {+/- 0.0033} seconds
D: 0.9500 containment intervals: {+/- 0.0085} seconds
D: 0.9973 containment intervals: {+/- 0.0251} seconds
R time: [04:56:38.1001]
R: 0.6800 containment intervals: {+/- 0.0033} seconds
R: 0.9500 containment intervals: {+/- 0.0085} seconds
R: 0.9973 containment intervals: {+/- 0.0251} seconds
Duration (R - D): 0.0359 seconds
Duration: 0.6800 containment intervals: {+/- 0.0052} seconds
Duration: 0.9500 containment intervals: {+/- 0.0120} seconds
Duration: 0.9973 containment intervals: {+/- 0.0316} seconds
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Bernard's light curve near/before the primary event |
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Close up of the possible secondary event. On the video playback, the star does look gone in a dark-ish sky background at this time. Each point is independently integrated in his camera. |
Light curve of secondary event and NIE histogram, 2.2 sigma significance. |
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