Globular cluster · Sagittarius

M55

Also known as: NGC 6809

mag 7.019′ across

About

M55 is a globular cluster of magnitude 7.0 in Sagittarius, about 19′ across.

M55 is in the constellation Sagittarius.
Best evenings: around late 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 49° 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.

EyesNot visible to the naked eye.
Binoculars (10×50)A fuzzy ball, brighter towards the middle.
Telescope (6–8 inch)Resolves into a swarm of stars at medium power, with a dense core.

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

Designations	M55, NGC 6809
Type	Globular cluster
Magnitude	7.0The smaller the number, the brighter.
Apparent size	19′the full Moon is 31′ across
Surface brightness	≈ 22.0 mag/arcsec²Estimate from the magnitude and size, per square arcsecond.
Constellation	Sagittarius
Right ascension (J2000)	19h 39m 59.4s
Declination (J2000)	−30° 57′ 44″