The Orion Q70 eyepiece view
LCD screen view.
Zoomed in, to show the target star is in the middle of a tight trio of stars. Will take some careful PyMOvie work to get good photometry.
This path goes centrally across Santa Cruz, which is very convenient. However, the rank is low so even on the centerline, the odds of a hit are only 47%. The 12.7 star is in the spout of the tea kettle of Sagittarius, at 20 degrees altitude in the SSE at azimuth 166. It should be do-able from the driveway. The asteroid is small enough that perhaps letting both Kirk and I to observe from home is OK. Or one can drive up to UCSC upper meadow. Karl should be in the mix too, with odds similarly in the 40's %. The target star will disappear completely for up to 2.5 seconds. It is very close to another similar magnitude star in a very dense area of the central bulge of our Milky Way so that will complicate things a bit. The value is in refining the orbit and if we get 3 good chords in defining the shape we also improve the orbit knowledge dramatically, for the benefit of future events.
The star in C2A is listed at 14.5 magnitude, as are the close neighbors on either side. However, I believe these are B magnitudes, and in this heavily dust obscured part of the sky, I will trust the V magnitude of 12.7. For our red-sensitive Watec 910hx cameras, it may be easier still. But at 20 degrees, it will definitely take some integration to get clearly.
The Orion Q70 eyepiece view |
LCD screen view. |
Zoomed in, to show the target star is in the middle of a tight trio of stars. Will take some careful PyMOvie work to get good photometry. |
Results:
A success! Clean calm moonless skies w/ no fog, and Kirk and I both got positive occultations from our respective homes.
Richard Nolthenius Results:
I set up at the base of my neighbor's stairs to get the star in the spout of Sagittarius just above the redwood tree tops from down the street. I used 8x on my Watec and had good calm conditions, not bothered much it seems from the lights in the area. The target star, unlike shown on the chart above, was a good 2 magnitudes brighter than the similar looking star images on either side of it. However, those two stars did contaminate my aperture in PyMovie, unavoidable. My PyOTE log file
PyMovie composite of tracking star (saturated pixels in the middle), target in green, and blank sky (red) |
Target star, with occultation in the middle |
PyOTE screen capture. I used 8x setting on my Watec. |
Zoom on the occultation. It did not go to zero because the two neighboring 14.5 stars were often inside the aperture. |
False positives histogram. The odds of my event being a false positive are 0.0000 |
Kirk Bender Results
Kirk used 16x on his Watec, and had a slight breeze and apparently more difficult conditions and pooer seeing conditions. Kirk's PyOTE log file
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PyMovie target light curve. Harder to judge sureness of event because his event was less than a second and integration was 16x or 1/4 second per integration. Not quite 4 points inside the occultation |
PyOTE light curve solution, zoomed in. |
