 Antares, the brightest star of Scorpius, is a red supergiant, spectral type M2. In binoculars it's a brilliant or appears like a red flame far away. Antares is about 500 light-years from us and 600 times larger than the Sun, easily big enough to encompass the orbit of Mars. Like other red supergiants, it has shown evidence of being oblong rather than round. Antares is the brightest member of the vast Scorpius-Centaurus Association of highly luminous young stars, which spills across several constellations and gives them their brilliance.
Bracketing Antares in the same binocular field is an association member: silvery bluish Sigma Scorpii, type B1. It's is a 3rd magnitude star and is located 2° from the central fire of Antares. A fine sight on a clear steady night through binoculars |  Antares, (Alpha Scorpii) a red super giant, is shrouded in nebulosity (lower left). Simga Scorpii is on the right and the magnificent M4 Globular Cluster is on bottom. NGC6144 is next to Antares, embedded in the nebulosity. |
| M4 is a globular star cluster tucked conveniently under the line from Antares to Sigma (see picture above). This object is the nearest globular clusters to the Solar System.
M4 can be detected by the naked eye at little more than 1 degree west of Antares.
It is one of the most loose globulars and it's diameter is about 55 light years.
Forty-three variables are known in it. In 1746, it was discovered by de Cheseaux and eventually added to the Messier catalogue. In 1987, a millisecond pulsar was discovered (a neutron star rotating once every 3.0 milliseconds) within M4.
In a pair of hand-held 7x50s binoculars you can detect M4 almost at first look. At a distance of 7,000 light-years, M4 may be the nearest of all the globular clusters. But it's less densely packed with stars than most. And, unfortunately, it's somewhat obscured by the clouds of interstellar dust that riddle this entire area. NGC6144 can be seen in the same spectacular, star-studded field, as a fairly faint "dot", looking in fact very much like M4 does under worse skies! |
 Antares and NGC6144 with M4 on the right. |
M NGC Con RA Dec Mag Size (min) Typ Distance Common Name --- ---- --- ------- ------ ---- ---------- --- -------- ------------- 4 6121 Sco 16 23.6 -26 32 7.5 26.3 GCl 7 |