Alert Notice 778: RY Ser observations needed now for HST coverage

June 6, 2022

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Further to AAVSO Alert Notice 758, Dr. Anna Francesca Pala (European Space Agency, ESAC, Spain) informs us that the dwarf nova RY Ser will be observed by the Hubble Space Telescope on June 10, 2022.

The exact time of the HST observations is:

2022 June 10 00:14:23 UT - 03:44:08 UT

Coverage is requested from now through June 17. Observations from the next few nights are crucial. Please observe RY Ser a few times per night tonight through June 12, then nightly through June 17. As with all targets for HST, it will be crucial to have a positive V measurement 24 hours before the scheduled HST time so the HST team can make a go-nogo decision.

A minimum SNR~20 is requested. If the target is too faint to obtain the minimum SNR in V, switch to CV. If a target is observed going into outburst, please submit your observation(s) as soon as possible and begin obtaining multiple observations per night.

Dr. Pala writes: "We know that some observers carry out time-series observations and also spectroscopy, and we welcome any additional contributions. Nonetheless the monitoring to assess quiescence should have the highest priority since, without it, there is the risk to lose the allocated orbits.

"In case of time-series observations, an uninterrupted light curve in a single filter (preferably B or V) would be better than alternating with different filters. CV observations can still be useful but V-filter observations should be the priority (whenever possible).

"DSLR observations, particularly if they are transformed to V, will be useful and are welcome. Visual observations will also be very valuable."

Coordinates for RY Ser (2000.0): R.A. 17 23 07.18  Dec. -12 48 09.7  (from VSX page for RY Ser)
Range: 13.6 - 16.6 V
Variability Type: UG

Charts with comparison stars for RY Ser may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations using the name RY SER to the AAVSO International Database.

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen using material provided by Dr. Pala.

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SUBMIT OBSERVATIONS TO THE AAVSO

Information on submitting observations to the AAVSO may be found at:
 - Photometry/visual observations: https://www.aavso.org/webobs
 - Spectroscopy: https://www.aavso.org/apps/avspec/

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