Types Of Telescopes For Astronomy

Types Of Telescopes For Astronomy

Fundamental Telescope Designs

The job of a telescope is to gather light, not to magnify an image (the eyepiece does that job). The bigger the target (the part 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 may acquire, the more element you will be able to seize, and in addition necessary for astrophotography, the shorter your exposures will should be to capture this detail.

Refractor Telescopes

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

Advantages:

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

-Due to the simple design they require little maintenance.

-Excellent for planetary and lunar viewing and photography.

-Wonderful for broad subject viewing and astrophotography especially in shorter focal lengths (more on this later).

-Because the objective is completely mounted and aligned there isn't any need for collimation (again more on this in one other article).

-Excellent color in apochromatic and ED (Extra Dispersion) designs.

Disadvantages:

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

-Can turn out to be bulky and troublesome to handle, particularly in bigger lens designs.

Newtonian Telescopes

This design was invented by Sir Isaac Newton (he of the apple on the head fame). Instead of a lens at the front of the tube this telescope design makes use of a concave, parabolic mirror to gather light reflecting it back towards the front 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.

Advantages:

-Lowest value per inch of all of the telescope designs.

-More light gathering power per greenback because of the decrease price design.

-Completely excellent color rendition.

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

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

-Can get glorious extensive-subject astrophotos and quick exposures in shorter focal lengths.

Disadvantages:

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

-Requires more upkeep, corresponding to collimation (discussed in one other article) which is significant for nice leads to your astrophotography, although you will 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 mixture of lenses and mirrors to collect and focus the light onto the eyepiece or Magnetic levitating Lamp Hampshire camera. The light enters the telescope by means of a thin 'lens' called a schmidt corrector plate, goes to the back of the scope to a spherical major mirror which reflects the light back towards the front. Here the light strikes another mirror, the secondary mirror which is mounted on the corrector plate. This secondary mirror then displays the light back towards the back where it is centered onto a gap within the primary mirror where the light is collected by an eyepiece or your astrophotography camera.

Advantages:

-Compact and portable.

-Low upkeep although as soon as once more collimation is required for prime performance.

-Many, many astrophotography equipment available.

-Cheaper per inch of aperture as compared with refractors.

-Glorious all-spherical telescope, good to excellent for both visible and astrophography.

-Excellent for planetary and lunar viewing and astrophotography.

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

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

Disadvantages:

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

-Lack of contrast due to the central obstruction which is even bigger than that in the Newtonian scopes.

-Attributable to their longer focal lengths the sphere of view is smaller and longer exposures are required for astrophotography, although a lens often known as a focal reducer is available which minimizes or removes this problem. The longer focal length is actually an advantage in planetary and lunar photography.

Follow Us on Facebook