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Observation by Alex Pratt: Video astrometry and photometry of PHA (...

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Alex Pratt


Alex Pratt


2020 Apr 24 - 20:33


2020 May 17 - 15:03

  • C11 f/10 with f/3.3 focal reducer
  • Watec 910 video camera
  • IOTA-VTI GPS time inserter
  • OccuRec (recorder)
  • Tangra (analysis)

Video integration settings between 0.16s and 0.64s



Target name

PHA (52768) 1998 OR2


Video astrometry and photometry of PHA (52768) 1998 OR2

About this image

I was able to monitor this Potentially Hazardous Asteroid during March and April. Its long-duration apparition and reasonable weather resulted in 90 GPS-timestamped video astrometric measures from 22 nights submitted to the MPC.

NEODyS use MPC data to derive an object's residuals in RA, Dec, magnitude and a chi-squared data quality assessment. The attached diagram shows these residuals from stations using standard CCD astrometry, my video astrometry (Z92) and another video observer (Z43).

NEODyS magnitude residuals are obtained from the tangle of G, R and V magnitudes submitted by observers. In the chi-squared results, values nearer to 0 are assessed as being better quality.

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