NGC 691 is an unbarred spiral galaxy located in the constellation Aries.

The total star formation rate of the galaxy is estimated to be about 0.6 M☉ per year.

It was discovered by Yoji Hirose in unfiltered CCD frames taken on Feb. 1.442 UT with a 0.35-m f/6.8 Schmidt-Cassegrain reflector.

The supernova was located 56" east and 1" south of the center of NGC 691 and at the time of the discovery had an apparent magnitude of 15.2.

[6] Spectrographic observations indicated it was a type Ia supernova about a week before maximum.