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(2111) Tselina occults UCAC4 491-028819


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About this observation
Alex Pratt
Time of observation
24/12/2018 - 21:52
Asteroid (2111) Tselina occults star UCAC4 491-028819
Observing location
C11 f/10 and f/3.3 focal reducer
Watec 910 video camera
IOTA-VTI GPS time inserter
OccuRec (recording)
Tangra and AOTA (reduction)
0.16s (4 integrated video frames)

The mag 14.5 27 km diameter asteroid (2111) Tselina was predicted to occult the mag 12.4 star UCAC4 491-028819 on 2018 December 24. Their combined magnitude would drop by 2.3 mag for up to 2.2 seconds.

My observatory was 1 km inside the predicted shadow zone. The predicted probability of success at my site was 21.1% and I recorded an occultation duration of 0.96s. The times of disappearance and reappearance were:-

D     21 52 25.87 +/- 0.08s

R     21 52 26.83 +/- 0.08s

The attached plot shows the analysis of the light curve using Tangra and AOTA software. No other observers were registered for this event, so we can't derive a shape profile, but a single positive observation can give high quality astrometry at the instant of the occultation.

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