M69 is a globular cluster located inside the prominent teapot asterism of Sagittarius. It shines at magnitude +7.6 and is therefore within the range of good quality 7x50 or 10x50 binoculars, although it appears faint and star like.

This globular is located 29,700 light-years from Earth and was discovered by Charles Messier on August 31, 1780. On this night he also discovered M70, which is a physically close neighbour of M69. Spatially, they are separated by just 1,800 light-years and any potential observers located on planets inside one of these clusters, would have a spectacular view of the other and vice-versa. Of course, this is assuming that the many thousands of bright stars, visible in their own backyard, didn't block the view of the other cluster.

Finding M69 is easy once one is familiar with Sagittarius. Start by focusing on the base of the teapot and then image a line connecting Kaus Australis (ε Sgr - mag. +1.8) with Ascella (ζ Sgr - mag. +2.6). M69 is positioned 1.5 degrees along and 2 degrees to the north of this line. There are two 5th magnitude stars located just south of the cluster.

M69 is best seen from the Southern Hemisphere during the months of June, July and August. From mid-northern latitudes, it's a difficult object that never climbs particularly high above the southern horizon.

Messier 69 globular cluster by the Hubble Space Telescope (credit:- NASA, The Hubble Heritage Team (AURA/STScI))

Finder Chart for M69 (credit:- freestarcharts)

Finder Chart for M69 - pdf format (credit:- freestarcharts)

Finder Chart for M6 (also shown M4, M7, M8, M19, M28, M62 and M69) (credit:- freestarcharts)

Finder Chart for M6 (also shown M4, M7, M8, M19, M28, M62 and M69) - pdf format (credit:- freestarcharts)

When viewed through 80mm (3.1-inch) refractors, M69 appears small with a bright centre surrounded by a faint halo. It looks somewhat like a comet but even at high powers isn't resolvable. Of the three Messier globulars (M54, M69 and M70) inside the teapot, M69 is the brightest. All three clusters are fine examples in their own right, but they suffer from small apparent sizes and are difficult to resolve with amateur scopes. Nevertheless, a 200mm (8-inch) reflector at high powers reveals M69 as a sharp centre that tails off gradually in brightness towards the outer edges. Averted vision helps, but to get the most out of this globular a larger scope is recommended.

In total, M69 has an apparent size of almost 10 arc minutes but visually appears much smaller. It's estimated to contain 125,000 stars and is extremely poor in variable stars. Outstanding twentieth century American astronomer Harlow Shapley couldn't find any variables and to date only 8 have been discovered.

M69 Data Table

Messier69
NGC6637
Object TypeGlobular cluster
ConstellationSagittarius
Distance (light-years)29,700
Apparent Mag.+7.6
RA (J2000)18h 31m 23s
DEC (J2000)-32d 20m 53s
Apparent Size (arc mins)9.8 x 9.8
Radius (light-years)42
Age (years)13.06 Billion
Number of Stars125,000
Notable FeatureOne of the most metal rich globulars known.

Sky Highlights - July 2017

The Planets
This Month's Guide

Algol Minima
Algol eclipse dates and times for July

Meteor Shower
Southern Delta Aquariids (Aquarids) meteor shower peaks on July 29

Northern Hemisphere
Evening
West:- Mercury (mag. -0.5 to +0.3) (second half of month)
Southwest:- Jupiter (mag. -2.0)
South:- Saturn (mag. +0.2)
Midnight
West:- Jupiter
South:- Saturn
East:- Neptune (mag. +7.8)
Morning
Southwest:- Saturn
South:- Neptune
Southeast:- Uranus (mag. +5.8)
East:- Venus (mag. -4.1)

Southern Hemisphere
Evening
West:- Mercury (second half of month)
Northwest:- Jupiter
East:- Saturn
Midnight
West:- Jupiter
North:- Saturn
East:- Neptune
Morning
West:- Saturn
North:- Neptune
Northeast:- Venus, Uranus

Deep Sky

Small telescopes:-
Messier 13 - M13 - Great Hercules Globular Cluster
Messier 92 - M92 - Globular Cluster
Messier 11 - M11 - The Wild Duck Cluster (Open Cluster)
Messier 7 - M7 - The Ptolemy Cluster (Open Cluster)
Messier 6 - M6 - The Butterfly Cluster (Open Cluster)
Messier 4 - M4 - Globular Cluster
Messier 8 - M8 - Lagoon Nebula (Emission Nebula)
Messier 16 - M16 - Eagle Nebula (Emission Nebula with Open Cluster)
Messier 20 - M20 - Trifid Nebula (Emission and Reflection Nebula)

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