It was discovered at 10:34 UT on 5 December 1986 by Mitsuri Suzuki, a 28-year-old school teacher living in Ena, Japan.

He photographed the portion of the Milky Way that passes through northern Andromeda with a 200-mm telephoto lens, and found the nova when its apparent magnitude was 8.0.

[7][5] OS Andromedae had an intrinsic decay time (for a three magnitude drop) of 25 days, making it a "fast" nova.

A sudden decrease in visual and ultraviolet light, which occurred 30 days after the peak, was due to dust formation during the nova event.

[4] At the estimated distance of 4.2 kiloparsec, its absolute magnitude at the peak was -7.56.