The AAVSO Circulars – See what’s been happening in the night sky as you plan your observing program!

The AAVSO has numerous observing aids designed to help you make the most efficient use of your valuable observing time. Each Observing Section and each mode of observing has a variety of resources – be sure to visit these pages and explore the links. The best place to start is the "Observing at a Glance – for Observers" page (

A very useful set of resources is the AAVSO Circulars. These publications are issued automatically every Friday morning (US Eastern time), and cover the preceding four weeks. They summarize observations submitted to the AAVSO International Database for all stars of the relevant type(s) for which the AAVSO has received data during that interval.

The four AAVSO Circulars cover the following types of variable objects:
      AAVSO AGN Circular – AGN, QSOs, and Blazars/BL Lac objects
      AAVSO CV Circular – Cataclysmic variables of all types
      AAVSO LPV Circular – Long Period Variables (Miras, semiregulars, symbiotics)
      AAVSO RCB Circular – R CrB variables

Each Circular includes for each star
    - star name
    - variability type
    - average magnitude for each date for which observations were submitted
    - observer codes of observers whose observations were used in determining that average

A table of all contributing observers is included at the end of the Circular. Samples of each Circular and a typical observer table are shown below.

Use these Circulars to see what “your” stars have been doing or find new stars to observe as you plan your observing. Is a CV in outburst (or overdue)? Is an RCB star fading (or finally approaching maximum after a prolonged fade)? Is your favorite Mira a lot fainter than you expected it would be at this point in its cycle? Are there only a few observations – or none – of stars that should be covered regularly? Is there unexpected behavior reported that you think should be followed up on? Let the Circulars assist, inform, and intrigue you!

To subscribe to any of these Circulars, please email Elizabeth Waagen ( Also, if you presently subscribe to a Circular and wish to change your address or unsubscribe, please let Elizabeth know.

                                              - Elizabeth O. Waagen, Senior Technical Assistant (Science Operations)
                                                Excerpted from Observer Corner, AAVSO Newsletter No. 78 (October 2018)

Samples of  AAVSO Circulars (showing format, content truncated)