So Many Telescopes!


Like venturing anto any new hobby, there is a multitude of choices. So many makes and models! But telescopes basically fall into one of two types: those that utilize a lens for the light-gathering element, and those that use a mirror for the same purpose.

Refractors employ a simple, and old, design. A compound lens, typically two elements, gathers photons of light and bends or refracts them down the length of the tube to a focal point, where the eyepiece picks them up. Refractors have been around longer. And with good reason: they are sturdy, easier to use, require little maintenance, and will provide a lifetime’s enjoyment, if properly taken care of.

Reflectors, as the name implies, employ a concave mirror (actually a parabolic-shaped curve) which reflects incoming photons of light, and bounce them to a secondary mirror, which in turn reflects them to the eyepiece. All modern, observatory-level telescopes are reflectors (including the iconic Hubble Space Telescope). While somewhat trickier to learn to use, and needing periodic alignment or collimation of the primary and secondary mirrors, reflectors are cheaper instruments, especially as you get into large aperture: “light buckets” (diameter of the actual light-gathering element).

Author's Stable of Telescopes: two refractors in foreground; reflector in the background.

Author’s Stable of Telescopes: two refractors in foreground; reflector in the background.

Advantages and disadvantages of each type?

Refractors, while easy to use (and are almost always the ones you will see in the background as a “prop” in a movie or television show), get very expensive as they get larger. Plus cumbersome. A traditional refractor with, say, an eight-inch lens would have a tube as much as eight to ten feet in length…in other words, you couldn’t transport the monster. It would require a permanent mount, and a shelter to enclose it.

Reflectors can be cumbersome too, but not not nearly to the degree of a refractor. An example of that same eight-inch aperture utilizing a mirror would be a significantly much shorter tube, ranging from as little as one foot in length to maybe five (more on the different types of reflectors later). While this relatively compact size makes for easier transport to a dark site, it also necessitates periodic realignment between the mirror elements. It’s a pretty easy task, but can be daunting for the novice astronomer.

There are other pros and cons associated with each type. Each camp has its enthusiasts as well as detractors. Fans of refractor telescopes swear by their pristine, razor-sharp planetary images, and “ink black” stellar backgrounds resulting from the greater contrast inherent in refractor telescopes. Reflector aficionados, on the other hand, applaud their relatively enormous light-gathering ability, especially when it comes to resolving detail on those “faint fuzzy” deep sky objects (again, galaxies, nebulae and star clusters).

For further analysis of the types of scopes and advantages/disadvantages of each, I cannot recommend a better link than the one following:

Astronomics, a mail-order company that sells a massive inventory of scopes and accessories, has a link on its home page: “How To/More Info”. There is an absolute wealth of unbiased information here. I strongly urge the beginner to do the homework and read up on the plethora of amateur instruments available today.

Decorum in this Forum merely allows me to scratch the surface of this subject!

Till next time,



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