[BAA-ebulletin 00664] (50000) Quaoar is predicted to occult an 11th magnitude star in Serpens on April 17.

[BAA electronic bulletins service]

On 2012 April 17, 0212 – 0234 UT, the Trans-Neptunian Object Quaoar is 
predicted to pass in front of, i.e occult, a magnitude 11.4 star which 
will be totally extinguished for a short time, the duration depending on 
the geographical location of the observer. An updated prediction issued 
on April 4 places the UK and Europe north of the region of greatest 
probability of an event; even so, predictions are uncertain, and 
monitoring the star for any occultation is desirable.

Interested observers can monitor the star visually or with CCD/video 
equipment. The aim is to record the time of disappearance and 
reappearance of the star to an accuracy of a few seconds (UT). This can 
be achieved with a continuous sequence of short CCD exposures
(e.g 1 to 3 sec) or by visual observation using stopwatches, lap timer 
or voice recorder. The total extinction of the star could last for up to 
1.8 minutes (108 seconds). Clocks in the equipment used, should be 
synchronised to UT so that the timings are reliable.

A prediction and star charts can be found at

http://www.maidenhead-astro.net/astocc/

The star is at an altitude of 15-20 degrees in the South East, so an 
unobstructed horizon is required.

For more information on this or other asteroid occultations, please 
contact the ARPS occultation coordinator. Negative and positive 
observations (timings) can be reported to:

Tim Haymes
Tvh.observatory at btinternet.com
Assistant Director (Occultations)
Asteroids and Remote Planets Section
2012 April 4