View here: Details for Crucial photometry requested for ASASSN-20pv HST observation
Abstract: UPDATED RE COORDS AND CHART 11/19/25. Further to AAVSO Alert Notice 838 (Alert Notice 838: Monitoring requested for 11 dwarf novae in support of HST observations in 2023-2024 (backup copy) | aavso), Dr. Anna Francesca Pala (European Space Agency, ESAC, Spain) informs us that the cataclysmic variable ASASSN-20pv (Gaia DR3 5360970516650651136) (Vel) is scheduled to be observed with the Hubble Space Telescope on 2025 November 28 (exact time not yet available). Please observe ASASSN-20pv in V nightly now through November 26, then a few times per night through Nov. 30, then nightly through Dec. 13. A positive V measurement 24 hours before the scheduled HST time is crucial so the HST team can make a go-nogo decision; the nights of November 26-27, 27-28, and 28-29 will be critical. See below for updated instructions. When the exact time is known, it will be posted in the forum given below. UPDATED Coordinates (2000.0): RA 10:40:19.4978928, Dec -49:51:29.693483. Coordinates are from the Gaia catalogue; high precision needed to separate target and companion.
Justification: ASASSN-20pv is the final target being covered in this four-year campaign on cataclysmic variables (extended by a year from its original three years). Optical coverage in V is essential to confirm that the target is not in outburst and so may safely be observed by HST. Without this confirmation, HST observations will not proceed. Optical coverage also allows for the HST observations to be analyzed in context of the optical behavior of the target. Coverage by AAVSO observers is therefore critical to this campaign.
