Spiral galaxy · Coma Berenices

M91

Also known as: NGC 4548

mag 10.25′ across

About

M91 is a spiral galaxy of magnitude 10.2 in Coma Berenices, about 5′ across.

M91 is in the constellation Coma Berenices.
Best evenings: around mid-May it is highest at about 9 pm (10 pm in summer time); a month earlier, two hours later.
Where on Earth: it is seen well, at least 10° up, from north of 66° S.

When it rises and sets tonight, how high it climbs and how much the Moon gets in the way are worked out in your browser for your place.

EyesNot visible to the naked eye.
Binoculars (10×50)Too faint for binoculars.
Telescope (6–8 inch)A faint oval glow with a brighter middle — no spiral arms without a camera.

For a dark country sky with no Moon. From a city, faint galaxies and nebulae can disappear completely.

Designations	M91, NGC 4548, PGC 41934, UGC 7753
Type	Spiral galaxy (Sb)
Magnitude	10.2The smaller the number, the brighter.
Apparent size	5′ × 4.1′position angle 150°; the full Moon is 31′ across
Surface brightness	23.2 mag/arcsec²Average over its disc, in the blue band: the lower the number, the easier it is to see.
Constellation	Coma Berenices
Right ascension (J2000)	12h 35m 26.4s
Declination (J2000)	+14° 29′ 47″