Open cluster · Sagittarius

M23

Also known as: NGC 6494

mag 5.527′ across

About

M23 is an open cluster of magnitude 5.5 in Sagittarius, about 27′ across.

M23 is in the constellation Sagittarius.
Best evenings: around early August 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 south of 61° N.

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.

EyesA faint smudge at the limit of vision, only from a dark site.
Binoculars (10×50)A rich scattering of stars — binoculars often give the best view.
Telescope (6–8 inch)Dozens of stars, many sharp and some coloured.

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

Designations	M23, NGC 6494
Type	Open cluster
Magnitude	5.5The smaller the number, the brighter.
Apparent size	27′the full Moon is 31′ across
Constellation	Sagittarius
Right ascension (J2000)	17h 57m 04.8s
Declination (J2000)	−18° 59′ 07″