Alert Notice 762: YZ LMi to be observed with HST - coverage needed now

December 21, 2021

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Further to AAVSO Alert Notice 758, Dr. Anna Francesca Pala (European Space Agency, ESAC, Spain) informs us that the SU UMa-type dwarf nova YZ LMi will be observed by the Hubble Space Telescope on December 30, 2021.

Coverage is requested to begin immediately and continue through January 20, 2022. Please observe YZ LMi a few times per night through December 30, then nightly until January 21. 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 YZ LMi (2000.0): R.A. 09 26 38.73  Dec. +36 24 02.5
Range: 16.3 g-20.5 CV
Variability Type: UGSU/IBWD+E

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

Please submit observations using the name GM AUR to the AAVSO International Database.

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


Information on submitting observations to the AAVSO may be found at:
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