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Lacerta

The Lizard

Constellation of the northern sky

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GenitiveLacertae
AbbreviationLac
Right Ascension21h55 to 22h56
Declination+34.9° to +56.8°
Area (sq deg)201
Brightest StarAlpha Lacertae
Optimum VisibilityOctober
Map of Lacerta
Relative Galactic Position of Lacerta

Lacerta outlines a region that falls between two spiral arms of our Galaxy: hence its stars are generally distant and faint as seen from Earth.

Sandwiched between some of the most prominent and recognisable constellations in the northern sky lies this innocuous zig-zag of faint stars.

Derivation

The sparse region between Andromeda and Cygnus was given various names during the seventeenth and eighteenth centuries. This constellation might have become Sceptrum, the Sceptre, or even Frederick's Glory in honour of Frederick of Prussia. Ultimately, though, the name given to it by Hevelius in 1687 was to survive: Lacerta, the Lizard.

Stars

There are no significant bright stars in Lacerta. Its brightest, Alpha Lacertae, is only of magnitude +3.8, and the constellation contains no other star above fourth magnitude. Some of these stars, such as Alpha and Beta Lacertae, are within two hundred light years of the Solar System, but are relatively lacking in luminosity. Others, such as the supergiant 4 Lacertae, are highly luminous stars, but they are thousands of light years from Earth, and so appear even fainter than the nearer stars of the constellation.

Deep Sky Objects

Though Lacerta is relatively lacking in interesting objects, it does lie on the Milky Way, and as we would expect it is not entirely devoid of features. In particular, there are two open star clusters in its northern parts, designated NGC 7209 and NGC 7243, which are slightly too faint to be seen without a telescope. These clusters both lie about three thousand light years from Earth.

Far, far beyond these clusters is a unusual object lying in the outer regions of the universe, the first of its kind to be discovered. This is BL Lacertae, a huge elliptical galaxy with a volatile core. The core variability can change vary rapidly over short periods of time, and for this reason BL Lacertae was at first mistaken for a variable star.

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