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Discovery of a Probable Nova in M81

ATel #17011; K. Hornoch (Ondrejov), A. W. Shafter (SDSU)
on 2 Feb 2025; 21:00 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Allen W. Shafter (ashafter@sdsu.edu)

Subjects: Optical, Nova, Transient

We report the discovery of a probable nova in M81 on a co-added 3000-s unfiltered CCD frame taken on 2025 Feb. 1.765 UT with the 0.65-m telescope at Ondrejov. The new object is faintly visible also on a prediscovery co-added CCD frame taken on Jan. 29.746 UT with the same instrumentation.

The object designated PNV J09550507+6909090 is located at R.A. = 9h55m05s.07, Decl. = +69o09'09".0 (equinox 2000.0), which is 150.3" west and 313.9" north of the center of M81 (see link to discovery image below).

Here we list the observing dates and corresponding photometry:
 
  Date [UT]    |  Mag   | Err  | Filter  | Telescope 
 
2025-01-26.834 | >21.8  |      | C       | OND 
2025-01-29.746 |  20.4  | 0.3  | C       | OND 
2025-02-01.765 |  19.8  | 0.15 | C       | OND 
 
As with all extragalactic novae, follow-up spectroscopic and photometric observations to determine the nova's spectroscopic class and rate of decline (speed class) are encouraged. The OND 0.65-m is a reflecting telescope at the Ondrejov observatory operated jointly by the Astronomical Institute of ASCR and the Astronomical Institute of the Charles University of Prague, Czech Republic. It uses a Moravian Instruments G2-3200 MkII CCD camera (with a Kodak KAF-3200ME sensor and standard BVRI photometric filters) mounted at the prime focus. The unfiltered OND photometry was calibrated against R-band comparison stars from Perelmuter & Racine (1995).

Discovery image