photometry

Special Notice #253: Request for Observations of MAXI J1836-194

September 10, 2011: Dr. Gregory Sivakoff (U. of Alberta) requests observations of the X-ray binary star MAXI J1836-194 as part of the JACPOT collaboration studying stellar radio jets from compact binaries.  There is no predetermined duration for this campaign, but observations are requested now to coincide with ongoing X-ray and radio observations.

Special Notice #245: Outburst of SV Ari

August 2, 2011:  SV Ari, a suspected WZ Sge star, has gone into outburst.  Rod Stubbings posted a 15.0 magnitude estimate on 110802.788 that has been confirmed by Gianluca Masi.  Gary Poyner says:

"Discovered by M & G Wolf on Heidelberg plates taken in November 1905 at mag 12.0p.  Kimpel & Jansch reported a possible sighting in September 1943, but this was not confirmed.  Nothing has been seen since."

Bob Nelson's Database of Eclipsing Binary O-C Files

Nelson Database of Eclipsing Binary O-C Files

Bob Nelson has developed over 5400 O-C (Observed - Computed) files of eclipsing binaries, all in Excel format, that we are hosting on our site. The purpose is to provide information on period variation for selected eclipsing binaries (for astronomers interested in a particular star) and to determine the best elements for predicting future eclipses.