Constellations

Coma Bernices is usually listed as Coma. The constellation of Serpens used to be two constellations separated by Ophiuchus; Serpens Cauda/Caudae [Snake's tail] and Serpens Caput/Caudae [Snake's Head]. Today we simply refer to the two snake chunks as one constellation.

For those who think that Latin is not only a foreign but a dead language, here is a quick guide on using the nominative and genitive forms. If you are talking about the constellation itself, use the nominative. For example, the southern constellation "Cen" is Centaurus. When you are talking about a part of the constellation, (the "something" OF the constellation name) use the genitive form. Continuing our example, the nearest star Toliman to the solar system is called Alpha Centauri because its is "the Alpha (brightest) star OF the Centaur.

If you really want to put on airs, try this quick guide to proper pronunciation of classical Latin. Things ending "ae" are pronounced roughly like the English word "eye". Things ending in "i" are pronounced with a long ee such as in "see". The letter "C" is the Latin equivalent of the English "K". For example, "Chamaeleon" is pronounced "kai-my-lee-yun" rather than "sha-meely-yun" as it would be in English. Similarly "Cancer" is "Kan-ker" rather than "Kan-sir". That being said, I have never heard anyone pronounce Alpha Centauri as "Alfa Ken-tore-ee" even if that is classically correct.

Now that you are Latin scholars, here are a couple of clinkers. The brightness is described by the classical Greek alphabet: The brightest star is Alpha, the next Beta and so on. It is a great idea except that red colored stars are notoriously under estimated and blue stars are overestimated. In no case, do these names reflect anything but naked eye brilliance.

    α:alpha   η:eta    ν:nu      τ:tau
    β:beta    θ:theta  ξ:xi      υ:upsilon
    γ:gamma   ι:iota   ο:omicron φ:phi
    δ:delta   κ:kappa  π:pi      χ:chi
    ε:epsilon λ:lambda ρ:rho     ψ:psi
    ζ:zeta    μ:mu     σ:sigma   ω:omega

In addition to the 87 recognized constellations, there are many asterisms which are so famous that people think of them as constellations. The Summer Triangle Lyra, Cygnus and Aquila portions, the Praesepe Beehive, the Pleiades Seven Sisters and the Hyades are common examples. They have no IAU (International Astronomical Union) designations beyond their constellation.

Constellations were officially designated in the 1930s. Boundaries were drawn along the then current celestial right ascensions and declinations. Today these boundaries have processed a small amount but the constellations still have their 1930's shape.

At one time stars were frequently located in two or more constellations, simultaneously. Sometimes the star bore two names which depended on which constellation you were considering. For example, Alpheratz Alpha Andromedae was a corner of the Great Square in Pegasus as well as the top of Andromeda's head. Today Alpheratz belongs to entirely in Andromeda.