Home
Site tour

Latest news
Society archive
News archive

Forums
Member's area

Calendar
About us
Location
Committee
Join us

Image gallery
Old Image gallery
Our observatory
Observing

Sky almanac
Deep sky
Weather

Web links

Search our site
Email us

M4
M4 in Scorpius is one of the closest globular clusters at approximately only 7200 light years, and one of the least concentrated. M4 can be detected by the naked eye under very dark skies (1.3 degrees west of Antares), and is prominent with the slightest optical aid. M4 is obscured by heavy clouds of dark interstellar matter which reddens the colour of the light from the cluster. It would be very spectacular if it was unobscured. Its angular diameter, seen on deep photographs, is about 36 minutes of arc, more than that of the Full Moon; this corresponds to a linear diameter of about 75 light years. M4 can be easily found as it is only 1.3 deg west of bright Antares, just south of the line to Sigma Scorpii. A round diffuse patch in binoculars, it is a circular glow in small telescope, and even a 4-inch resolves the brightest stars, which are of about mag 10.8. Larger telescopes show a halo of stars around the bright central portion of the cluster to a diameter of over 16 arc minutes. (Image: SEDS)

M6 & M7
Two fine open clusters in Scorpius, quite easy to find if you have a good horizon. The Butterfly Cluster (M6) and Ptolemy's cluster (M7 - shown). Open cluster Messier 6 is described by Burnham as a "charming group whose arrangement suggests the outline of a butterfly with open wings." M6 has about 80 cluster members, spread over a region about 54 arcmin in diameter. The main portion of the cluster fills a field of about 25' angular diameter at a distance of approximately 1600 light years. M7 is a large, bright group easily detectable with the naked eye. M7 consists of about 80 stars brighter mag 10 in a field of about 1.3 degrees apparent diameter which at its distance of perhaps 800 light years corresponds to a linear extension of 18 or 20 light years. (Image: SEDS)

M39
M39, a fine open cluster in Cygnus, is a very large but very loose open cluster, situated some 9 degrees east and a bit north of Deneb (Alpha Cygni). Its distance is only about 800 light years, and it is of intermediate age (estimates between 230 and 300 million years). 30 stars are proven members and contained in a volume of about 7 light years diameter. It's apparent visual brightness is 4.6 magnitudes. This cluster is best observed with lowest powers because of its considerable angular size of 32 arc minutes, more than the Moon. (Image: SEDS)

M57 - The Ring Nebula 
M57 is the truly fabulous planetary nebula known as the Ring Nebula was discovered in Antoine Darquier de Pellepoix in 1779. It is often regarded as the prototype of a planetary nebula. Recent research has confirmed that it is actually a ring of bright light-emitting material surrounding its central star. M57 is very easy to locate as it is situated between Beta and Gamma Lyrae, at about one-third the distance from Beta to Gamma. It can be seen with binoculars as an almost stellar object, difficult to identify just because of its small apparent diameter. In smaller amateur telescopes, the ring becomes apparent at about 100 magnification, with a darker middle; a 12th-mag star is east of the planetary nebula, about 1' of the centre. (Image: STScI)

M22
M22 is a relatively nearby globular cluster that is stuck firmly in the middle of a rich milky way star field. It was probably the first globular cluster discovered, by Abraham Ihle in 1665. M22 is a very remarkable object. At 10,400 light years, it is one of the nearer globular clusters. Its 32' angular diameter is sligtly larger than that of the Full Moon. It is visible to the naked eye for observers at not too northern latitudes, as it is brighter than the Hercules globular cluster M13. It is the third brightest overall, outshone by only Omega Centauri (NGC 5139) and 47 Tucanae (NGC 104) (Image: SEDS)