Occultation of USNO-B1 0742-0417905 (15m2) by (50000) Quaoar on 2012 Feb 17 for Europe

Based on astrometry from the RIO group for Europe and updated by other astrometry an occultation of a 15m1 star can be observed in the morning of the 17^th of February 2012 at 4h 30min UTC.

The occultation is very well in reach of many video and digital camera systems attached to telescopes as small as 8 inch. We urgently ask everybody, to take part in the international campaign for observation.

The goal is to determine the diameter of Quaoar and find out, if the TNO has an atmosphere. Therefore, not only the determination of the exact time point of dis- and reappearance is necessary, but also the exact determination of the lightcurve during dis- and reappearance of the star behind the disk of Quaoar.

On this site, more infos will be posted, to give you informations about how to observe. The RIO astrometry group, leaded by Marcelo Assafin, has made astrometric observations with large telescopes, to define the position of the star as well as possible in the milliarcsecond range.

There will be no more accurate astrometry on the star or Quaoar, because right now the star is too close to the sun, to provide high accuracy astrometry.

More informations about final updates of the astrometry can be found on Felipe Braga-Ribas (LESIA) Website about this and other actual events.

The occultation track

Including the last updates from Felipe, the occultation track is shown as follows: