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(521) Brixia occults TYC 1977-01111-1


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About this observation
Alex Pratt
Time of observation
13/02/2018 - 22:41
Asteroid (521) Brixia and star TYC 1977-01111-1
Observing location
C11 f/10 and f/3.3 focal reducer
Watec 910 video camera
IOTA-VTI GPS video time inserter
Tangra and AOTA
0.16s (4 integrated video frames)

On 2018 February 13 the mag 12.3 111km diameter asteroid (521) Brixia was predicted to occult the mag 12.3 star TYC 1977-01111-1. Their combined magnitude of 11.7 would drop by 0.77 mag for up to 8.6 seconds.

My observatory was inside the predicted shadow zone. The predicted probability of success at my site was 96.9% and I recorded an occultation duration of 4.16s. It was fascinating to watch the asteroid approaching the star, then they merged and the occultation occurred. The times of disappearance and reappearance were:-

D     22:41:00.46 +/- 0.08s

R     22:41:04.62 +/- 0.08s

The attached plot shows the analysis of the light curve using Tangra and AOTA software.

There were 18 stations across Europe logged in OccultWatcher for this event and 11 have reported positive (light drop) observations. This is one of the best observed occultations by this main belt asteroid, producing a good shape profile from the multiple chords. It can be viewed here.

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