vendredi 11 juillet 2008

Pisces 8

The sun passes through the southeast corner of Pisces; in fact the vernal equinox now lies in Pisces.
Pisces is depicted as two fish connected by their tails at the star alpha Piscium. Indeed, alpha's name, "Al Rischa", means "the cord".

The constellation is rather faint; Pisces' stars are generally fourth magnitude. There are a few fine binaries, an interesting variable, and one Messier object: a splendid face-on spiral, which unfortunately is quite faint and rather a challenge for smaller telescopes.

Double stars:
Alpha Piscium (Struve 202) has an orbit of 933 years (considerably more than the 720 years previously thought): 4.3, 5.2; currently PA 223 degrees, separation 1.6".

Zeta Piscium (Struve 100) is a fine binary: 5.6, 6.5; 63 degrees, 23" separation.

Eta Piscium is a difficult binary to resolve: 3.5, 11; 36 degrees, 1" separation.

Psi1 Piscium (Struve 88): 5.3, 5.5; 160 degrees, 30" separation.

Struve 61 (65 Piscium) is a splendid binary of equal stars: 6.3, 6.3; 297 degrees, 4.4" separation.

The binary is found just on the border with Andromeda. The easiest way to find it is to start from zeta Andromedae, then move north 3 degrees and east half a degree.

Variable stars:
Kappa Psc is an alpha CV variable: 4.87-4.95.
TX Psc (19 Psc) is an interesting irregular, a deep red star that changes only slightly (about 5.0 to 5.5, although some references say from 5.5 to 6.0). Its main attraction is in the exceptionally deep redness of the star.

The star is found between iota and lambda, north two degrees from lambda and one degree east. Or you might find it easier by first starting at gamma Psc and moving seven degrees east. (Burnham, p. 1475, has a finder's chart.)

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