OGLE-IV Pre-discovery Observations of Nova Sagittarii 2023
ATel #15914; P. Mroz, A. Udalski (Astronomical Observatory, University of Warsaw), on behalf of the OGLE team
on 23 Feb 2023; 10:29 UT
Credential Certification: Przemek Mroz (pmroz@astrouw.edu.pl)
Subjects: Optical, Cataclysmic Variable, Nova
We report pre-eruption photometric observations of Nova Sagittarii 2023 (CBAT #5225, ATel #15910, ATel #15911). The nova was first detected on images taken on 2023 Feb. 18.834 UT (CBAT #5225). The object is located in the field BLG838 that has been observed by the OGLE-IV project since 2017. We measure its equatorial coordinates of 17:56:27.88, -17:14:53.4 (J2000). The progenitor of the nova shows irregular variability in the magnitude range 16.48 < I < 18.07 mag with a mean brightness of I = 17.30 +/- 0.04 mag. The last pre-eruption image was taken on 2023 Feb. 18.38 UT (HJD 2459993.87735), when the object was I = 16.864 +/- 0.015 mag. We also measured I = 11.638 +/- 0.003 mag on 2023 Feb. 23.37 UT (HJD 2459998.86793).
