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Astronomy 103, Summer, 2006

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Astronomy 103

Star Naming

You will see a variety of different names for stars on star charts. The most commonly used ones are described here. The descriptions below will use as an example the stars in the constellation Aquilla. The plot of this constellation on your SC-001 star chart is shown below:


Common Names

The brightest stars are given proper names. For example, the brightest star in Aquilla is Altair. Many of the stars with which you will become most familiar with will have names like this that you use (Vega, Deneb, Altair, Fomalhaut, Betelgeuse, Rigel, Regulus, Polaris, etc.)

Bayer Names

While only the brightest stars have proper names in common use, a larger set of stars have Bayer names. These are the stars which you will see labelled with a greek letter on the star chart. They are usually named so that α is the brightest star in a constellation, going on down through the greek alphabet as stars get dimmer. Not every constellation will have all letters in the greek alphabet used on your star charts. Stars with proper names generally also have Bayer names.

These names are the greek letter followed by the possessive form of the constellations name. For instance, Altair is also known as α Aquilae. When written, the contellation possessives are often given a three-letter abbreviation, e.g. α Aql. Just northwest of Altair is γ Aquilae, or γ Aql. On this page (from Jim Kaler at UIUC) you can find a table of the posessive and abbrevation forms of all the constellations.

In case you aren't familiar with the greek alphabet, here's a cheet sheet:

αalpha νnu
βbeta ξxi
γgamma οomicron
δdelta πpi
εepsilon ρrho
ζzeta σsigma
ηeta τtau
θtheta υupsilon
ιiota φphi
κkappa χchi
λlambda ψpsi
μmu ωomega

Flamsteed Names

The flamsteed names number all the stars brighter than a certain magnitude in a constellation from east to west. All of the stars with a Bayer name also have a Flamsteed name. However, if a star has both, it's more common to use the Bayer name.

For exapmle, to the southwest of λ Aql is 12 Aquliae. Few of the other stars in the example above have their Flamsteed name shown on the chart, because the stars all have Bayer names. You will much more often deal with stars that have common or Bayer names than stars that have Flamsteed names. When stars have all three, you will usually use the common name or the Bayer name.

Catalog Names

As if two or three names weren't enough, may stars have several other names. There are a number of catalogs that list all of the stars in the sky down to a certain magnitude limit, or stars chosen by some other criteria. For example, the Henry Draper catalog lists Altair as HD 187642. The Smithsonian Astrophysical Observatory catalog lists Altair as SAO 125122. In Astronomy 102, you will probably never have to worry about the sundry catalog names of any stars.

The astronomical catalog site SIMBAD will show you the vast number of names that some stars have; you can also find references to the astronomical literature for various objects at that page.

Buy a Star Name— a Hoax!

Various outfits will allow you to part with your hard-earned cash in exchange for having a star named after you. Don't do it.

Even if they don't outright lie, these outfits do everything they can to mislead you into believeing that these star names are somehow "official". They aren't. Even if they go into some bound volume in a safety deposit box in Switzerland, no astronomer is going to care. Heck, I could write on a piece of paper that I'm the King of England and bury it on Alumni Lawn, but that still wouldn't get me into the British tabloids.

No astronomer recognizes or uses the names of the stars that you can "buy". We use Bayer, Flamsteed, or catalog names for stars. The people who are selling you the names of stars aren't selling you anything other than a piece of a star map, a meaningless certificate, and a bunch of misleading rhetoric. If you want to name a star after yourself, white out the word "Sirius" on your SC-001, write in your own name, make yourself up a certificate on your computer, and for nearly no cost you will have the brightest star in the sky named after yourself! And, what's more, it will be just as meaningful and official as it would have been if you'd payed more than a hundred dollars to have some dim anonymous star named after you.

Last modified: 2005-August-18, by Robert Knop

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