Alert Notice 787: V485 Aqr being observed by HST this week

July 25, 2022

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Further to AAVSO Alert Notice 783, Dr. Anna Francesca Pala (European Space Agency, ESAC, Spain) informs us that the Hubble Space Telescope will observe the dwarf nova V485 Aqr on:

2022 July 29  00:34:33 - 06:17:04 UT

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. Dr. Pala writes: "Any observations that you can provide in the next days will be the most crucial to assess the safety of the target for the HST detectors. Given that the HST observations will occur on the night between Thursday and Friday, the data collected on Wednesday night will be decisive to allow the HST team to give its final approval."

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 continues: "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 (2000.0) and other information:

V485 Aqr:  R.A. 20 44 48.92   Dec. -04 59 28.8 (from VSX page for V485 Aqr)
Range: 14.3 - 17.1 V
Variability Type: UG

Charts with comparison stars for V485 Aqr may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations using the name V485 AQR 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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