Choosing the Right Telescope

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Everything I sell in my ebay shop I have a personal interest in, and every item either reflects my Christian faith or my belief that all the best Hobbies are educational.

Click below for my current stock of telescopes.

 Stampman Astonomy Domain

I saved for two years to buy my first telescope for £30.00 in 1968 ironically the quality of that Scope is no better than the current starter scopes I can sell today for around the same price.
Let's get started by learning about the several different types of telescopes to choose from. Each type has their advantages and disadvantages.
You might notice that when you touch a display model in a local shop or department store that the telescope wobbles quite a bit. Not a problem when you're looking AT the telescope, but when you're looking THROUGH the telescope at 50 to 100 power, that movement is magnified 50 to 100 times! There's not much hope of seeing detail on planets or other heavenly objects when they're whizzing around in the eyepiece!

When reading the instructions for your new telescope you may see the scope comes with all sorts of accessories (depending on model) such as solar screens, barlow lenses, camera adapters, etc., etc. The scope in the picture looks real impressive with all those gadgets dangling from it. In reality those things are added to the telescope to help improve performance for experienced onbserver, not to help beginners. Most of those accessories would be rarely used by a knowledgeable telescope user, but you won't know that until you bring it home and try to use it.

The Myth of "POWER"! Here's the real pitfall that traps new telescope buyers, the word Power or Magnification. Many telescope sellers tout the word power as if to imply that the more powerful a telescope is, the better it is, and that's not true. You'll see "500X" or higher in the ebay adds or on the side of the box. In fact, most amateur astronomers rarely use more than 200X on any given night, and most likey they use less than 100X most of the time.

The Earths atmosphere is very unsteady, you can see this whenever you see a star twinkle in the night sky. When you use a telescope to look at a celestial object, that twinkling is magnified by the telescope, making the image of a star or planet seem to "boil" in the eyepiece. Some nights are steadier than others, and that's when you can use moderate magnification. But most nights aren't so steady, so you need to keep the magnification low. Even very large high quality telescopes are rarely used at much more than 300X on very good nights. So the idea of using 300-500+ on a beginners telescope is pretty far fetched.

When looking for a telescope don't worry about power, what's more important is the QUALITY and diameter of the main lens or mirror, this is also known as its "aperture". In telescopes, if quality was equal, then bigger would better. The lens or mirror of a telescope is its light collector. the larger the lens or mirror, the brighter the images will be, and assuming good quality, the sharper the image will be. You might see a label on a telescope that says D=60mm, that means the telescope has a main lens of 60mm diameter. You might read an ad that describes a 4 inch telescope, that's not its length, that's the diameter of the telescopes mirror.
If you're a child or a beginner a good size refractor would be 50 to 90mm. (2-4 inches)  A good size reflector for a more serious Astronomer might have a mirror of 90mm-150mm (4 to 8 inches). The size you choose depends on two things, your budget, and your back. You want the biggest telescope you can afford, but you don't want one too big to lift. If it's heavy, you probably won't want to use it after the first few outings and it'll sit collecting dust. Reflectors over 8 inches start to weigh in at over 50 lbs., doesn't sound like much until you have to carry it across your lawn in the dark. Furthermore if purchasing a larger scope quality is everything, consider sticking to a reconized brand like Tasco, Meade, Telstar etc. Where possibe I would recomend buying new if possibe, with larger reflectors even with normal use the aluminium coating will eventually wear away. Re coating is a job for the professional, not for the amateur. 

Telescope (from the Greek tele = 'far' and skopein = 'to look or see'; teleskopos = 'far-seeing') is an instrument designed for the observation of remote objects. The term usually refers to optical telescopes, but there are telescopes for most of the spectrum of electromagnetic radiation and for other signal types.

A refracting or refractor telescope is a dioptric telescope that uses a lens as its objective to form an image. The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used in other devices such as binoculars and long or telephoto camera lenses

A typical refractor has two basic elements, a convex objective lens and an eyepiece lens. The objective in a refracting telescope refracts or bends light at each end using lenses. This refraction causes parallel light rays to converge at a focal point; while those which were not parallel converge upon a focal plane. This can enable a user to view the image of a distant object as if it were brighter, clearer, and/or larger. Refracting telescopes can come in many different configurations to correct for image orientation and types of aberration.

A reflecting telescope (reflector) is an optical telescope which uses a combination of curved and plane (flat) mirrors to reflect light and form an image (catoptric), rather than lenses to refract or bend light to form an image (dioptric). The Italian monk Niccolo Zucchi is credited with making the first reflector in 1616, but his inability to shape the concave mirror accurately and the lack of means of viewing the image without blocking the mirror, caused Zucchi to give up on the idea. It was another 54 years before British scientist Sir Isaac Newton implemented the first reflector circa 1670. He designed the reflector in order to solve the problem of chromatic aberration, a serious degradation in all refracting telescopes before the perfection of achromatic lenses. The traditional two-mirrored reflecting telescope is known as a Newtonian reflector.

While the Newtonian focus design is still used in amateur astronomy.

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