Scorpius 7

The star table indicates just how bright many of Scorpius's stars are; in fact the constellation is one of the brightest of the larger constellations.
Alpha Scorpii is better known as Antares ("Rival of Mars"). This is one of the four Royal Stars of the ancients, along with Aldebaran, Regulus, and Fomalhaut. It glitters with an unusual metallic red while the entire region is bathed in a pale red nebula, lit from the same star.
This red supergiant has a visual binary that just might be visible, depending on local conditions and the size of one's scope (see below). The star is estimated to be between 285 sun diameters to about 700 suns. It's 600 light years away.
Due west 1º (about half the distance to sigma Sco) is the bright globular cluster M4, while another globular cluster, M80, is 4º NNW of Antares. See below for these deep sky objects.


Double stars in Scorpius:

Alpha Scorpii is a visual binary which may be difficult to resolve due to the brightness of the primary. Try a moonlight night, which should cut the glare of the brighter star: 1.1, 5.4; PA 274º, separation 2.6".
The companion is usually described as green in colour, probably a visual effect created by the red glow of Antares. The star is estimated to orbit its primary every 900 years.
Beta Scorpii. This superb double has a pleasant colour contrast: white and bluish-green. 2.6, 4.9; PA 23º, 13.7".
Nu Scorpii is a multiple system, a "double-double". That is, each of the visible components (AC) is also a primary of a closer component; these are termed AB and CD.
AC: 4.4, 6.4; 337º, and 41" separation.AB: 4.4, 5.4; PA 2º, 1.3".CD: 6.3, 8.0; 51º, 2.3".
Xi Scorpii is also a multiple system, a system which also includes the next binary system as well (Struve 1999).
Components AB form a close binary with period of 45.7 years. The companion is now gradually drawing away from the primary: PA 308º and separation 0.39".
Sigma Scorpii: a double with faint companion. AB: 2.9, 8.5; PA 273º, separation 20".
Struve 1999 is gravitationally attached to the Xi Scorpii system, although at a distance of about 7000 AU (an "AU"--astronomical unit-- being the distance of the earth from the sun).
The binary is found just south of Xi Scorpii, two yellow stars of nearly equal brightness: 7.4, 8.1; 99º, 11.6".


Variable stars in Scorpius:

RR Scorpii is the brightest long-period variable in the constellation, with a visual magnitude range of 5.0-12.4 every 281.45 days. In 1999 the maximum should occur around the end of May.