Using Big (or any) Telescopes

We are bounded in a nutshell of Infinite Space: Free Form #8: Using Big (or any) Telescopes

One of the most important skills necessary for any astronomer is the ability to use and prepare telescopes in order to view everything we have talked about the last couple of months. First off, know your different types of telescopes. There are 3 main, widely used telescopes: Refractors, Reflectors, and   Catadioptric telescopes.

The Thirty Meter Telescope
http://blogs-images.forbes.com/alexknapp/files/2015/06/top-view-of-tmt-complex-1940x1089.jpg

Each of these has its advantages, but there is a reason for each. Getting Catadioptrics out of the way, they are huge and very expensive telescopes which work with a large back mirror which pools the light into an aperture just above the focusing mirror. This is the type of telescope one would use to observe deep space objects, and as such are usually the type built in places like Mauna Kea in Hawaii, and in the Atacama Desert in Chili. However, these telescopes are almost entirely motorized and have little value for the regular star-gazer, so we shall focus on ones we can readily use.

Moving on, another key telescope type is the Newtonian Reflector, which operates very much like a Catadioptric telescope, but shifts the light from the pooling mirror into an aperture on the side of the telescope, as seen below:

A Newtonian Reflector
http://ecx.images-amazon.com/images/I/51r8pTAaiKL._SX466_.jpg

Furthermore, Reflectors are very powerful telescopes since they can pool much more light than refractors (as we shall see in a moment), and can thus see farther into the night. They are usually heavier than refractors, but this is offset by their impressive angular resolution. Reflectors are used by looking into the aperture on the side of the telescope, after the light has been pooled into the aperture.

The other kind of telescope is the Refractor, a model which has gone virtually unchanged since Galileo Galilei used them. These are very long telescopes which condense light into a lens which is then pooled by a secondary lens which we observe through. Although possibly not the best kind of telescope, it is one of the most versatile and easily usable. Refractors need to be very large to see at long distances, which is how they end up in large observatories.

The Great Refractor- CfA
https://www.cfa.harvard.edu/figs/grref.gif

An observatory for a refractor has a fairly simple construction an operation. After identifying the object you wish to observe, one closes doors which would let in harsh light into the observatory, shuts off any of these lights interior to it, and turns on red lights which hardly make a difference when observing, like a dark room used in photography. Next, the dome is opened and subsequently rotated to the desired object, on which the telescope is pointed to after placing the aperture, removing the cloth over the main lens of the refractor, and turning on the motor which turns at one revolution per day (if you happen to have one of these), which helps keep the telescope trained on the object. These are the basic skills necessary to operate a telescope, aside from knowing where to observe (preferably away from urban areas) and when (most definitely not while it is raining). Happy Observing!