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Observation by Alex Pratt: (73995) 1998 FQ25 occults UCAC4 625-0132...

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Alex Pratt


Alex Pratt


2020 Nov 30 - 18:40


2020 Dec 02 - 22:42



  • C11 f/10 and f/3.3 focal reducer
  • Watec 910 video camera
  • IOTA-VTI GPS time inserter
  • OccuRec (recording)
  • Tangra and AOTA (reduction)

0.08 s



Target name

(73995) 1998 FQ25 occults UCAC4 625-013281


(73995) 1998 FQ25 occults UCAC4 625-013281

About this image

You wait weeks for a successful asteroidal occultation observation, then two come along within a few days.

Mag 18.5 outer main-belt asteroid (73995) 1998 FQ25, 7.4 km in diameter, was to occult a mag 12.1 star in Perseus on the night of 2020 November 30. Observers within the 9 km wide shadow track could see a 6 mag drop in brightness for up to 0.6 s.

I was inside the predicted shadow zone, with 3.2% probability of success. The prediction was accurate and I recorded a dip lasting 0.5 s:

   D: 18 40 39.77 ± 0.06

   R: 18 40 40.27 ± 0.04

This is the first observation of an occultation by this asteroid.

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