Spiral galaxy · Coma Berenices

M100

Also known as: NGC 4321

mag 9.47′ across

About

M100 is a spiral galaxy of magnitude 9.4 in Coma Berenices, about 7′ across.

M100 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 64° 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)A faint smudge, only from a dark site.
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	M100, NGC 4321, PGC 40153, UGC 7450
Type	Spiral galaxy (SABb)
Magnitude	9.4The smaller the number, the brighter.
Apparent size	7′ × 6.4′the full Moon is 31′ across
Surface brightness	22.6 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 22m 54.8s
Declination (J2000)	+15° 49′ 18″