Telescopes

Celestron

The word "telescope" is derived from the Greek τῆλε, tele "far" and σκοπεῖν, skopein "to look or see"; τηλεσκόπος, teleskopos "far-seeing", and was coined in 1611 by the Greek mathematician Giovanni Demisiani after Galileo Galilei's telescope was presented at a banquet at the Accademia dei Lincei.

[hide][top]Reflector Telescopes

Reflector Telescopes

Advantages of Reflector Telescopes (including Newtonian types)

Color-free images
Relatively cheaper in relation to aperture
Often shorten tubes than an equivalent aperture refractor
Easier observing positions
Good light grasp in large sizes

Disadvantages of Reflector Telescopes (including Newtonian types)

Temperature changes affect adjustment
Telescope tube not sealed
More maintenance necessary
Scatter of light by 'spider" support of secondary mirror can be detrimental to the image
Spider generates star diffraction patterns

[hide][top]RefractorTelescopes

Refractor Telescopes
see the detailed page here: Refractor telescope

Advantages of Refractor Telescopes

Little adjustment required
Maintenance virtually nil
Closed tube minimizes tube currents
No refracting obstructions.
Often longer tubes than an equivalent aperture reflector (with exception of newer fast shorty tubes)
Telescope tube is sealed
High contrast views
No central obstruction

Disadvantages of Refractor Telescopes

Temperature changes affect adjustment
Colour effects can be annoying
Much more expensive than other telescopes in relation to aperture
Longer tube can be a nuisance
Mounting must be high for observation near the zenith

[hide][top]Catadioptric Telescopes

Includes SCT Schmidt Cassegrain Telescopes and Maksukov Cassegrain Telescopes.

Advantages of Catadioptric Telescopes

Shorter tubes for easy storage
Can be pushed to very high magnification
Closed tube minimizes tube currents
Telescope tube is sealed
Excellent for planetary and double-star viewing and imaging because of the higher focal ratio / maximum obtainable magnification level.

Disadvantages of Catadioptric Telescopes

Large central obstruction
The tube is heavy and needs a sturdy mount
High focal ratio make it tough to do deep sky astrophotography and long exposure astroimaging
Long cool-down times

[hide][top]Telescope Mounts

Telescopes require mountings to be used effectively and to provide stable views at high magnifications.

See also Telescope Mount

[hide][top]Care of Telescopes

see Telescope Care

[hide][top]Telescope eyepieces

see eyepiece

Telescopes

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