Ophiucus 9

Double stars in Ophiuchus:
Ophiuchus has one of the finest collections of double stars, including several close visual binaries.
Eta Ophiuchi is a close visual with an orbit of 88 years: 2.9, 3.4; presently the companion is at PA 247º and separation 0.6".
Lambda Ophiuchi is also a rapid binary. 4.2, 5.2; currently the PA is 27º and its separation is 1.5".
Xi Ophiuchi: 4.5, 9.0; PA 50º, separation 3.7".
Rho Ophiuchi: 5.3, 6.0; PA 344º, 3.1".
Tau Ophiuchi: 5.2, 5.9; with an orbit of 280 years. Presently the companion is at PA 282º and separation 1.7".
36 Ophiuchi is a binary with period of 548 years, of two equal stars: 5.1, 5.1; 148º, 4.9".
70 Ophiuchi is another close binary with a period of 88.3 years. 4.2, 6.0. In 2000.0 the values are PA 149º and separation 3.7".
Struve 2276. This is a very beautiful fixed binary of two fairly faint stars: 7.0, 7.4; PA 257º, separation 6.9".


Variable stars in Ophiuchus:
Kappa Ophiuchi is an irregular (Lb) variable that fluctuates betweem 4.1 and 5.0.
Chi Ophiuchi is a gamma Cas variable: 4.2-5.0.
U Ophiuchi is an Algol type (EA) variable: 5.84-6.6 every 1.7 days.
X Ophiuchi is a long-period variable, 5.9-9.2 with a period of 328.85 days. In the year 2000 the maximum should occur during the last week of March.