May 7, 2024
AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Campaigns and Observing Reports: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024
- Cataclysmic Variables: https://www.aavso.org/hst-campaign-dwarf-novae-2023-2024-01
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Further to AAVSO Alert Notice 838, Dr. Anna Francesca Pala (European Space Agency, ESAC, Spain) informs us that observations of the cataclysmic variable ASASSN-20pv (Vel) have been scheduled with the Hubble Space Telescope for:
2024 May 30 UT
When the exact time is announced, it will be reported in the above forum threads.
Beginning May 17, please observe ASASSN-20pv in V nightly from through May 23, then one to a few times per night through May 30, then nightly through June 9. 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; the nights of May 27-28, 28-29, and 29-30 will be critical.
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."
ASASSN-20pv has a range of 12.3 g - 17.4 V and variability type UGSU/IBWD. The most recent observations of it in the AAVSO International Database show it at magnitude 17.177 V +/-0.017 on 2024 May 06.08137 UT (T. Rutherford, Blountville, TN) and visual magnitude <15.6 on May 05.56960 UT (R. Stubbings, Tetoora Road, VIC, Australia).
Coordinates: R.A. 10 40 19.50 Dec. -49 51 29.7 (from VSX entry for ASASSN-20pv)
Charts with comparison stars for ASASSN-20pv may be created using the AAVSO Variable Star Plotter (VSP).
Please report all photometry observations to the AAVSO International Database using the name ASASSN-20pv. Reduce and submit observations as soon as possible after making them.
This Alert Notice was compiled by Elizabeth O. Waagen using information provided by Dr. Pala.
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