Alert Notice 790: ASASSN-14cn to be observed with HST

August 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 ASASSN-14cn (Dra) will be observed by the Hubble Space Telescope on September 01-02, 2022.

The exact time of the HST observations is:

01 Sep 2022 23:46:01 - 02 Sep 2022 08:33:58 UT

Coverage is requested from now through September 5. Dr. Pala writes: "The data collected on the night of Wednesday August 31st and Thursday September 1st will be the most crucial to assess the safety of the target for the HST detectors. It would be very helpful if you could try to obtain two or three positive measurements per night (in V or CV), from today till the 2nd." Then, please make nightly observations through September 5. 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 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 for ASASSN-14cn (2000.0): R.A. 16 11 33.97  Dec. +63 08 31.9 (from VSX page for ASSSN-14cn)
Range: 13.6 - 18.7 V
Variability Type: UG/IBWD+E

Charts with comparison stars for ASASSN-14cn may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations using the name ASASSN-14cn 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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