Alert Notice 600: Dates for R Aqr Chandra and HST observations

October 1, 2017 : Further to AAVSO Alert Notice 589, the likely windows for the Chandra and HST observations of the symbiotic variable R Aqr have been set as follow:

Chandra: 2017 October 11 - October 15
HST: 2017 October 13

As stated in Alert Notice 589, Dr. Karovska requests visual and photometric (UBVIJH; CCD/PEP/DSLR) observations, and optical spectroscopy, including in the Halpha, [OIII]5007A region, in order to monitor the state of the system and correlate with the satellite observations.

Dr. Karovska requests the following cadence of observations:

now through 2017 October 9, twice per week
October 10 - 15, nightly
October 16 - 23, twice per week
October 24 - December 15, once per week

She adds: "Also requested is high-speed photometry in U and B bands (a cadence of as low as a few seconds would be ideal, but a cadence of about a minute may also be all right) to reveal any possible high-speed variations in the central binary."

R Aqr, which has a range of ~ V = 5.2 - 12.4, is currently at magnitude V ~ 10.0 and fading, according to observations in the AAVSO International Database.

Coordinates (2000): RA 23 43 49.46  Dec. -15 17 04.2

Charts with a comparison star sequence for R Aqr may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations to the AAVSO International Database using the name R AQR.

This campaign is being followed on the Campaigns and Observation Reports Forum at

Observers are reminded that R Aqr is the target of another AAVSO observing campaign underway, this one to detect the next eclipse of this symbiotic system, predicted for 2022 but which may come early (AAVSO Alert Notice 535).

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.


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