This event is nice and long, being due to the large asteroid Brixia, at 8.2 seconds. However, the target is faint and low in Libra at Alt=26 Az=224 in the SW. I've set out a marker at Sunlit Lane, on the center line. The target should be over the tree at the south end of the air field, approximately. The path is so wide that anywhere in the SC Mtns is a "sure thing" for a positive. Best to try and separate widely for this one. If there's no fog, the that will be easier. However, there is another long event just 4 minutes later (!) and that has a much narrower path. So, we'll have to take what Nature gives us and position ourselves according to that event, by Glia.
The target is in Libra, halfway between the top of the scale's triangular top, and the top star in the head of Scorpio.
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Kirk and I got data, he from home, me from Sunlit lane. Under clear dry skies. Karl bumped the scope before the event and couldn't get it back on target on time. No data.
I recorded at 8x, from Sunlit Lane on the edge of the driveway just east of the airfield. Skies were clear, seeing was fairly stable. While I could see no detectable clouds, there are correlated changes in brightness beween the reference stars, suggesing very thin aerosols perhaps. The reference star calibrated light curve of the target looks flat, without waves. I could see the target star and Brixia separated well, an hour before the event. On the external monitor, the two objects looked equal in brightness.
magDrop report: percentDrop: 45.1 magDrop: 0.652 +/- 0.088 (0.95 ci)
DNR: 2.44
D time: [08:58:01.6031]
D: 0.6800 containment intervals: {+/- 0.0777} seconds
D: 0.9500 containment intervals: {+/- 0.2413} seconds
D: 0.9973 containment intervals: {+/- 0.6081} seconds
R time: [08:58:09.7630]
R: 0.6800 containment intervals: {+/- 0.0777} seconds
R: 0.9500 containment intervals: {+/- 0.2413} seconds
R: 0.9973 containment intervals: {+/- 0.6081} seconds
Duration (R - D): 8.1599 seconds
Duration: 0.6800 containment intervals: {+/- 0.1260} seconds
Duration: 0.9500 containment intervals: {+/- 0.3472} seconds
Duration: 0.9973 containment intervals: {+/- 0.7669} seconds
Waviness in the ref stars are clearly correlated. Sky transparency changes? |
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Target was adequately bright at 8x. |
Although the sky looked clear, I got a minimum in the flatness by this rather bumpy smoothing curve, perhaps thin aerosols? Moving the smoothing interval larger than 24 made the fit distinctly worse. Moving in time in either direction made the flatness worse also. |
The mag drop calculated was 0.65, but given the slight clipping of the sky, and the resulting slight upward bias in the sky level, a drop of 0.8 actual, is reasonable.
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FP test passed far beyong the 5-sigma level. |
Recorded at 8x integration setting. Kirk's confidence limits are slightly worse than mine, but that may be a combination of the 20% lower light per setting for NTSC vs. PAL, and also that I observed at 2,000 ft elevation vs Kirk's more coastal ~100 ft elevation. Or that at least seems like a reasonable explanation.
Kirk's best smoothing interval setting was also rather small, showing a bumpy optimal light curve in the reference star, similar to what I saw from Sunlit Lane.
magDrop report: percentDrop: 46.7 magDrop: 0.683 +/- 0.109 (0.95 ci)
DNR: 2.21
D time: [08:58:01.5625]
D: 0.6800 containment intervals: {+/- 0.0806} seconds
D: 0.9500 containment intervals: {+/- 0.2810} seconds
D: 0.9973 containment intervals: {+/- 0.6793} seconds
R time: [08:58:09.0365]
R: 0.6800 containment intervals: {+/- 0.0806} seconds
R: 0.9500 containment intervals: {+/- 0.2810} seconds
R: 0.9973 containment intervals: {+/- 0.6793} seconds
Duration (R - D): 7.4740 seconds
Duration: 0.6800 containment intervals: {+/- 0.1360} seconds
Duration: 0.9500 containment intervals: {+/- 0.3982} seconds
Duration: 0.9973 containment intervals: {+/- 0.8355} seconds
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