Note: The HST observations were successfully obtained. Please continue to observe R Aqr until further notice. - Elizabeth O. Waagen, July 6, 2021
Note: The Chandra observations have been completed. The HST observations will take place 2021 May 13 10:57:01 - 18:08:28 UT. - Elizabeth O. Waagen, May 4, 2021
April 5, 2021
Note: Continued observations, particularly in B, V, and visual, are needed now and through the coming year. R Aqr is presently approaching solar conjunction and observations are very difficult, but they are extremely important as R Aqr is also approaching minimum. Please observe as long as possible now and pick up again as soon after conjunction as possible. - Elizabeth O. Waagen, 1 February 2021
Note: Continued observations in all bands (particularly B and V) and spectroscopy are extremely important. Please continue nightly observations until further notice. - Elizabeth O. Waagen, 31 January 2020
Note: The exact schedules for the Chandra and HST observations of R Aqr (Alert Notice 689) are as follow:
Chandra (UT) Note that this date is EARLIER than given in Alert Notice 689.
12 Jan 2020 00:13:21.409 - 12 Jan 2020 14:06:41
Note: Dr. Margarita Karovska (Center for Astrophysics|Harvard & Smithsonian) is also urgently requesting BVRI photometry, visual observations, and spectroscopy of R Aqr through (at least) the end of the observing season. - Elizabeth O. Waagen, August 5, 2019
Note: R Aqr is out of its seasonal gap and is increasingly observable. Continued coverage is requested as described below until further notice. - Elizabeth O. Waagen, May 3, 2019
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
Note: This campaign has been extended through the 2018 observing season.
August 4, 2017: Dr. Margarita Karovska (Harvard-Smithsonian Center for Astrophysics) has requested "visual, photometric, and spectroscopic observations of the symbiotic variable R Aqr in preparation for and in support of Chandra and HST observations currently scheduled for October 2017."
Ongoing visual, photometric, and spectroscopic observations of R Aqr about once every 10 days are requested, both to detect and observe the next eclipse and to continue the light curve of this star that has been in the AAVSO observing program for over a century. Elizabeth O. Waagen, August 2017, March 2019
December 1, 2015
The long period variable R Aquarii is an extremely interesting system. Its type is both Mira (M) and symbiotic (ZAND) - R Aqr is a close binary system consisting of a hot star and a late-type star, both enveloped in nebulosity. In the case of R Aqr, the late-type star is a Mira. As a result, the very interesting light curve shows not only the Mira pulsation but also eclipses as the two stars interact.
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