S Andromedae

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**Supernova 1885**
Observation data (Epoch ?)

Supernova type	Ia
Remnant type	{{{SNRtype}}}
Host Galaxy	Andromeda Galaxy
Constellation	Andromeda
Right ascension	00^h 42^m 44^s
Declination	+41° 16′
Galactic coordinates	{{{gal}}}
Discovery Date	20 August 1885 UTC
Peak magnitude (V)	6
Physical characteristics
Progenitor	Unknown
Progenitor type	Unknown
Colour (B-V)	1.31
Notable features	First and only supernova observed in Andromeda; first extragalactic supernova observed

S Andromedae (also SN 1885A) was a supernova in the Andromeda Galaxy, the only one seen in that galaxy so far by astronomers, and the first ever noted outside the Milky Way. It is also known as "Supernova 1885".

It was discovered on August 20, 1885 by Ernst Hartwig, working at Dorpat (Tartu) Observatory in Estonia. It reached magnitude 6, but faded to magnitude 16 by February 1890.

The star was reported to be reddish in color and declined very rapidly in brightness, which is atypical for Type Ia supernovas. Unfortunately no spectroscopic data is available.

In 1988, astronomer R. A. Fesen and others, using the 4-meter Mayall telescope at Kitt Peak, discovered the iron-rich remnant of the explosion. Further observations were made with the Hubble Space Telescope in 1995.