How to choose your first telescope?

Everyone who is in love with space dreams of buying a telescope but is often left disappointed because of their high prices. Telescopes are not cheap. Especially, the high quality ones.

This is because they are high precision equipment. Small errors during their manufacture can sometimes produce out of focus images which is certainly not desirable.

A telescope in general has five important parts namely:

  • the aperture,
  • the eyepiece,
  • the optical tube,
  • the finderscope and
  • the mount (Refer the figure below).
telescope.png
Parts of a telescope

The aperture of a telescope represents the amount of light that the telescope can gather. The larger the aperture, the brighter the object would appear. Eyepiece is that part of a telescope where you keep your eye to view the final image of an object. Eyepieces come in a variety of focal lengths. Remember that the final magnification provided by the telescope is the ratio of the focal length of the telescope to the focal length of the eyepiece. So an eyepiece of focal length 4 mm would provide a magnification of 300 times in a telescope of focal length 1200 mm. Smaller the focal length of eyepiece, more will be the magnification.

The optical length of a telescope is the length of the main tube. The finderscope is used to identify the location of objects in the sky before peeping into the eyepiece whereas the mount supports the tube.

Telescope types

The most common types of telescopes available in the market are Reflecting telescopes and Refracting telescopes.

Reflecting telescopes use mirrors to reflect light and are usually short and wide in appearance. These type of telescopes are best to view deep-sky objects like galaxies, star clusters, nebulae, etc. Large space telescopes like the Hubble Space Telescope are generally reflecting ones.

Refracting telescopes on the other hand are slim and long. These telescopes use lens to bend light. They are one of the best telescopes for beginners and provide excellent views of relatively larger and brighter objects like our Moon and the planets like Jupiter, Mars, etc.

Another variety of telescopes is the Catadiotropic telescope. These telescopes use both lens and mirrors and can be used to view bigger and brighter objects as well as deep-space objects.

Now that you know about the basics, you’re ready to choose your very own telescope. While choosing a telescope, check for the type of telescope you wish to buy. Also, look at the description of the equipment and find its magnification, aperture size, optical length, etc and compare them based on the information provided above.

Telescope suggestions for beginners

If you are a beginner, the best suggestion would be to start stargazing using a binocular and become an expert in finding the location of objects in the sky. Today, there are a large number of star tracking apps available online for free which ease this task.

Finally, when you’re confident enough to buy a telescope, choose the kind of telescope (reflecting, refracting or catadiotropic) depending on the type of objects that you wish to see. Do not forget to compare the telescope models based on their aperture, magnification of eyepiece, highest useful magnification and resolution.

My personal recommendations for beginners are Celestron Astromaster 130EQ and Orion SpaceProbe II 76mm Altazimuth Reflector Telescope.

Good luck to you!

Note that the views provided in the article are based on my personal knowledge and experience.

 

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