April 27, 2022
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Further to AAVSO Alert Notice 758, Dr. Anna Francesca Pala (European Space Agency, ESAC, Spain) informs us that the cataclysmic variable GP Com will be observed by the Hubble Space Telescope on April 29-30, 2022.
The exact time of the HST observations is:
2022 April 29 23:22:51 UT - April 30 01:54:27 UT
Coverage is requested from now through May 20. Observations from tonight and tomorrow night are crucial. Please observe GP Com a few times per night tonight through April 30, then nightly through May 20. 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 GP Com (2000.0): R.A. 13 05 42.40 Dec. +18 01 03.8
Range: 15.7 - 16.2 V
Variability Type: IBWD
Charts with comparison stars for GP Com may be created using the AAVSO Variable Star Plotter (VSP).
Please submit observations using the name GP COM 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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