Station Map for the Occultation by (9) Metis at Monday, 2008 December 29 (~ 22:53 UT)
Good Test for Video Equipment
V-Magnitude of target star TYC 0637-00036-1: 12.0 mag
Johnson B-V Colour Index: + 1.3
The UCAC2 gives a „pseudo-R magnitude“ of 11.8 mag
The combined light of star and asteroid will be ~ 9.8 mag (the magnitude of the asteroid) during an occultation!
„Occult Watcher“ indicates (9) Metis as suspected binary asteroid!
The max duration is expected to be 35.5 sec with a max drop of 0.13 mag only.
David Dunham (IOTA) wrote about this small drop in magnitude:
„This occultation by a large asteroid and a fainter star provides a good test of video equipment, to see what can be recorded, preferably from several sites so that the consistency of results can be assessed from a fit of the observed chords. Metis‘ mag. will be 9.8 while that of the star is only 12.0, producing a magnitude drop of 0.13 (or 0.16 in red).
Tony George recorded a similar event in 2006 (see below), but nobody else recorded it. We are trying to see how small the mag. Drop can be and still obtain reliable results from video, so this Dec. 29th event is a good opportunity for that. Recently, a few IOTA observers in the southern USA recorded an occultation of a faint star by (4) Vesta with a mag. drop predicted to be only 0.01, and Limovie analysis failed to find the occultation in any of the recordings; that small a drop is too small for our video equipment to reliably detect. Other events with mag. drops of 0.2 have been successfully recorded with video equipment in the USA.“
Tony George about his experience and the event at Dec 29:
„I successfully observed an occultation by Metis in 2-13-2006. It was video recorded. I defocused the target star to make sure pixels were not saturated. The mag drop was 0.12, similar to this event. The SNR was 0.64, relatively low, but the event is clearly visible in the data. This would be a good one for multiple chords.“
The event will take place at an altitude of 30 deg and at azimuth 251 deg. The sun will be at an altitude of -60 deg. (At predicted centre line for longitude E 10 deg)
There is a 1 sigma uncertainty interval of ± 0.15 path widths.
The probabilities to see a positive event:
Centre line: ~ 100 %
Path limits: ~ 50 %
1 sigma lines: ~16 %
2 sigma lines: ~ 2 %
(Calculation according to Raymond Dusser, E.A.O.N. Circular #10)
PLEASE REMEMBER: Predictions are sometimes wrong. Please observe even with a small probability.
Let other observers know about you observing plans: Announce you station with OccultWatcher !
More information (coordinates, finder charts) at Steve Preston’s prediction:
Table of potential observing stations and cities with distance from center of predicted path (Derek C. Breit):
Good luck with your observation,