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Types Of Telescopes For Astronomy

Types Of Telescopes For Astronomy

Primary Telescope Designs

The job of a telescope is to gather light, not to magnify an image (the eyepiece does that job). The larger the target (the half that collects the light) whether or not it's a lens, in refractors, or a mirror, in reflectors, the more light the telescope will collect. The more light you can acquire, the more detail you can be able to capture, and in addition vital for astrophotography, the shorter your exposures will must be to seize this detail.

Refractor Telescopes

The type of telescope most people visualize once they hear the word telescope is the 'Refractor'. This is what Galileo used for his break-through discoveries. A refractor has an objective lens at the entrance which passes the light straight by means of to the back of the tube, focusing this light at an eyepiece or for astrophotography a camera.


-No central obstruction (see more within the reflecting scopes), giving higher contrast.

-Because of the simple design they require little maintenance.

-Excellent for planetary and lunar viewing and photography.

-Excellent for wide field viewing and astrophotography particularly in shorter focal lengths (more on this later).

-Because the objective is completely mounted and aligned there is no such thing as a want for collimation (again more on this in another article).

-Glorious shade in apochromatic and ED (Extra Dispersion) designs.


-Costlier per inch of aperture (objective) than reflectors and catadioptric telescopes.

-Can turn into bulky and troublesome to handle, especially in larger lens designs.

Newtonian Telescopes

This design was invented by Sir Isaac Newton (he of the apple on the head fame). Instead of a lens on the entrance of the tube this telescope design uses a concave, parabolic mirror to collect light reflecting it back towards the entrance of the tube to a flat diagonal mirror which displays the light out the side of the telescope to the eyepiece or camera for astrophotography.


-Lowest value per inch of all the telescope designs.

-More light gathering power per greenback because of the lower value design.

-Absolutely excellent coloration rendition.

-More compact design compared to a refractor of comparable light gathering ability.

-Glorious distinction for planetary and lunar astrophotography and viewing in longer focal lengths.

-Can get wonderful broad-field astrophotos and quick exposures in shorter focal lengths.


-Slight lack of distinction because of the central obstruction (the flat secondary mirror) as compared to a refractor.

-Requires more upkeep, akin to collimation (discussed in one other article) which is vital for nice leads to your astrophotography, though you'll learn how to do this shortly with practice.

Schmidt-Cassegrain Telescopes

This is a highly regarded design, with a high tech look. Often known as a CAT (Catadrioptics). They use a combination of lenses and mirrors to collect and focus the light onto the eyepiece or camera. The light enters the telescope through a thin 'lens' called a schmidt corrector plate, goes to the back of the scope to a spherical main mirror which displays the light back towards the front. Right here the light strikes another mirror, the secondary mirror which is mounted on the corrector plate. This secondary mirror then reflects the light back towards the back where it's focused onto a gap in the major mirror where the light is collected by an eyepiece or your astrophotography camera.


-Compact and portable.

-Low maintenance although as soon as again collimation is required for high performance.

-Many, many astrophotography accessories available.

-Cheaper per inch of aperture as compared with refractors.

-Excellent all-spherical telescope, Headphones online Hampshire good to superb for both visible and astrophography.

-Excellent for planetary and lunar viewing and astrophotography.

-Excellent to excellent for DSO (Deep Space Object) astrophotography with a caveat (see the disadvantages).

-Excellent to glorious optics, each Meade and Celestron are putting out excellent optics on a consistent basis.


-Costlier per inch of aperture as compared with Newtonian telescopes.

-Lack of contrast because of the central obstruction which is even bigger than that within the Newtonian scopes.

-Because of their longer focal lengths the sector of view is smaller and longer exposures are required for astrophotography, although a lens referred to as a focal reducer is available which minimizes or removes this problem. The longer focal size is definitely an advantage in planetary and lunar photography.