Vietnamese Chinese (Simplified) English Japanese Korean Russian
Types Of Telescopes For Astronomy

Types Of Telescopes For Astronomy

Primary Telescope Designs

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

Refractor Telescopes

The type of telescope most individuals 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 on the entrance which passes the light straight through to the back of the tube, focusing this light at an eyepiece or for astrophotography a camera.


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

-Due to the easy design they require little maintenance.

-Wonderful for planetary and lunar viewing and photography.

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

-Because the objective is completely mounted and aligned there isn't a need for collimation (once more more on this in another article).

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


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

-Can grow to be bulky and troublesome to manage, especially 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 on 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 reflects the light out the side of the telescope to the eyepiece or camera for astrophotography.


-Lowest cost per inch of all the telescope designs.

-More light gathering energy per dollar because of the decrease cost design.

-Completely good coloration rendition.

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

-Wonderful contrast for planetary and lunar astrophotography and viewing in longer focal lengths.

-Can get glorious large-discipline astrophotos and brief exposures in shorter focal lengths.


-Slight loss of contrast as a result of central obstruction (the flat secondary mirror) as compared to a refractor.

-Requires more maintenance, reminiscent of collimation (discussed in another article) which is vital for nice ends in your astrophotography, although you'll learn how to do this rapidly with practice.

Schmidt-Cassegrain Telescopes

This is a very fashionable design, with a high tech look. Often known as a CAT (Catadrioptics). They use a mix of lenses and mirrors to collect and focus the light onto the eyepiece or camera. The light enters the telescope by a thin 'lens' called a schmidt corrector plate, goes to the back of the scope to a spherical primary mirror Astranaut Art 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 is targeted onto a hole within the main mirror the place the light is collected by an eyepiece or your astrophotography camera.


-Compact and portable.

-Low maintenance though as soon as again collimation is required for top performance.

-Many, many astrophotography accessories available.

-Cheaper per inch of aperture as compared with refractors.

-Glorious all-spherical telescope, good to very good for each visible and astrophography.

-Very good for planetary and lunar viewing and astrophotography.

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

-Very good to glorious optics, each Meade and Celestron are placing out excellent optics on a consistent basis.


-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.

-On account of their longer focal lengths the sector of view is smaller and longer exposures are required for astrophotography, though 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.

With Us

  • Certification
  • Mission
  • Vision
  • Departments
  • Company


Đang cập nhật

Đang cập nhật

Board of Directors   -   0904 845 678   -   0915 630 064

Equipment leasing division :     -   0917 527 547
Human Services lease :          -   0126 894 5152
Services provided materials and equipment orders :  -  0986 820 844   -  0907 879 588

Fabrication and mechanical products / construction :
0982 889 694

NamPhuongXanh Company

Dong Xuyen Industrial Zone, P. Rach Dua, Vung Tau

Tel.: +84 643 522 003 / 597 277 / 615 861

Fax : 0643 524 379

Email : ;

Photo gallery