The different Types of Sky Maps

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"The different Types of Sky Maps"
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Sky cartography, the practice of drawing maps of objects and places in the sky, has two distinct types: 1) maps used by astronomers to identify objects found in the night sky, and 2) those that are used to identify the geography of different places in the Universe such as our Moon, Mars, or the Milky Way galaxy. These both range from the simple to the complex, from those designed for amateurs to those used by professional astronomers.

The most fundamental of the maps is the planisphere. Because our Earth is rotating and orbiting, the location of celestial objects changes with the hour, the time of year and your location. So, a printed star map for one location at one particular time may not help you to identify the objects you see in the night sky. A planisphere, however, is able to adjust, taking these factors into consideration. You can buy a simple cardboard planisphere, or you can make one yourself . The diagrams you need are available on several internet sites. Print and trim these diagrams, and attach the two together so they are centered and can rotate freely. A pin, or something similar, works well for holding them together.

Using a planisphere is easy. Simply dial the planisphere so that the time on the inner ring lines up with the date on the outer ring. You will also need to be sure that if the planisphere is pointing north, so are you. The size of the star on the planisphere is based on its brightness, not the size it appears to be in the night sky.

Atlases with large quantities of star maps are also available. Each map, however, will be of specific times in specific locations. For one to be useful, you will need a map that corresponds to your place and time.

Different maps are designed for different degrees of magnifying the night sky. Some are useful with the naked eye, some are intended for use with a pair of binoculars, and others require telescopes. Depending on the map, it could be used with the cheapest available telescope, or may require a space-based telescope such as the Hubble telescope. You will need to choose a map that works with your equipment.

There are also computer programs that can provide you with precise, up-to-date maps. These are particularly useful when you are very close to either the equator or the poles. To use these you will need to know your latitude and longitude. These programs can be displayed in a variety of ways, from a simple printed copy, to information that can be stored on your handheld

The second major group of maps is those that are of a specific object or location. Such maps will label the features of an object. So, for example, a map of the moon would label places such as craters and plains. Any space object that has labeled locations on it has a map that labels these.


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