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TELESCOPES

3

mounts
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MOUNTS

2 BASIC TYPES
telescopes
INDEX

Alt-azimuth and Dobsonian mounts

mounts
alt-azimuth The idea of an alt-azimuth mount is to enable the telescope to move simply up and down and round and round. Alt-azimuth is a two angular system used to locate the position of an object on a celestial sphere. This type of mount is named after the system, but cannot be used to locate objects in the sky using degrees because it can not be referenced to the position the telescope is on the earth which needs to be known. This can be done with the other common type of mount called the equatorial mount (see below). The Dobsonian mount is also an up and down, round and round mount but was designed by John Dobson as an inexpensive way to mount large reflecting telescopes. No astrophotography can be done with these mounts, but photographs can be taken during the day, of daytime objects because they don't need to be tracked unlike the moving night sky.
TELESCOPE LINKS:
Basics
Light Gathering Power
Closer Look At Refractors
Closer Look At Reflectors
Dimensions
Balancing
For more information on equatorial mounts go to Astrophotography or
Eyepieces
Balancing.
Cleaning Optics
Equatorial mounting systems
These are the mounts which can be used to track the night sky. The night
sky is always moving due to the earth rotating. The mount tracks the
object by way of a motor drive or slow motion controls, which are turned
by hand to keep the object located in the eyepiece. The equatorial mount
can track objects because of it's ability to be aligned to the north or south
celestial pole (SCP or NCP) according to the telescopes position on the earth. Make out the earth's rotation is on a shaft which is running directly through the North and South Poles and the shaft continues out into space. The ends of the shaft are the north and south celestial poles and all the
stars rotate around them as our perspective of the Earth turning. The telescope has to know the position on earth because simply, as when your in the Southern hemisphere you look north to the Sun, but if you live in the Northern Hemisphere, the Sun is in the south.
Tips
Astrophotography
Build your own telescope
Build your own telescope
for schools
Binoculars
Equatorial mounts are used for astrophotography or just to keep the object
tracked in the eyepiece for comfortable viewing, free from the vibrating
movements of always moving the mount. When the mount is positioned
correctly, one is able to use the degree wheels to locate objects according
to their co-ordinates.

Final word on mounts!
A mount is as important as the telescope! If you double a given
magnification, you are halving the field of view. When viewing intricate
details on a planet, like its cloud, band or ring systems at around 200x
magnification, your only seeing a small area of sky and the image will not
take long to travel from one side of the eyepiece to the other. If a telescope
Dobsonian
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