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What are star charts?
Home » Astronomy » Star Charts » What are star charts?Star charts are portions of the celestial globe printed in a flat format. They might come in a variety of sizes and printing styles but they all have a common ground—they’re expressed in terms of Right Ascension (RA) and Declination (Dec)—just like latitude and longitude. The stars are plotted as dots—the brighter the star, the larger the dot.
On almost all star charts, the primary stars of any constellation are expressed with Greek letters—alpha for the brightest and omega for the dimmest. Another common point is the symbols used to denote types of sky objects—such as a circle with a cross through it for a globular cluster, or an oval for a galaxy.
Some charts include constellation boundaries, while others give constellation lines. Many include Bayer or Flamsteed numbers for some bright stars... And all list catalog object numbers such as M16 for Messier object 16, or NGC 7331 for New General Catalog object 7331.
Don’t be scared. They are really quite easy to use once you become familiar with them and most have keys to the symbols and Greek letters printed on each page.
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