eclipsing binary

The 2022 Eclipsing Binary Ephemeris and 2022 RR Lyrae Ephemeris are now available.

Many thanks to Gerry Samolyk for all his hard work putting these two valuable documents together!

Note: Please continue to observe ASASSN-21co to help build a long-term light curve.  -  Elizabeth O. Waagen, January 3, 2023

March 2, 2021

Note:  Please continue observations at a cadence of 1 observation per week until further notice. - Elizabeth O. Waagen, July 6, 2021

Please continue observations at a cadence of 1 observation per week at least through 2021 June 15. See the post by Principal Investigator Dariusz Kubicki in the forum threads for this campaign (URLs below).  -  Elizabeth O. Waagen, 2020 June 29

The eclipse of EE Cep has occurred but continued monitoring is requested to establish post-eclipse behavior.  - Elizabeth O. Waagen, 2020 May 21

August 17, 2017: In AAVSO Alert Notice 593 we announced a campaign on the very long period VV Cep M2Iabe+B0/2Ve binary. The amplitude of the eclipse was wrongly given as slightly under a magnitude in the V band when it is actually around 0.1 mag. This means that the VV Cep eclipse is largely undetectable visually,  and is not a good candidate for visual observations. CCD and DSLR photometry, however, are still encouraged.

Edit: The information given in this alert notice has been updated to correct eclipse depth values. Please see AAVSO Alert Notice 594

August 16, 2017: The AAVSO is requesting monitoring of the eclipse of the very bright Algol-type eclipsing binary variable VV Cep, predicted to have begun in June 2017 and to conclude in November 2019.

June 30, 2017: Dr. Octavi Fors (University of North Carolina at Chapel Hill) and colleagues have requested AAVSO observers' assistance in following up on some targets from the Evryscope survey.

June 8, 2017:  Dr. Milena Ratajczak (University of Wrocław) has requested AAVSO observers' assistance in monitoring the very bright (V = 4.23) and very unusual eclipsing binary HD 148703 (HR 6143, N Sco) during its infrequent primary and secondary eclipses scheduled for 2017 June 11 and June 14, respectively.