Mnemovore

Which is the best telescope ? …Dobsonians ? Maybe? …

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A question asked by amateur astronomers all the time, beginners and experienced. Well the best answer finally is the scope that you use all the time. The same goes for bicycles. The same goes for everything. As a species we are nomadic, expansionist and of course garbage collectors. We enjoy having something for every situation. But back to the subject..

There are 2 types of scopes. Reflectors and refractors. Reflectors use mirrors, refractors use lens. Also there are 2 types of mountings. Equatorial and Altazimuth. There are some reflector types..Newtonians, Cassegrains (Maksutov-Cassegrain, Ritchey-Chrétien(Hubble telescope) and Dall-Kirkham).

One type of reflector that uses the altazimuth mounting and the Newtonian type tube is the Dobsonian telescope. Taken its name by John Dobson, a former monk of the Ramakrishna Order and amateur astronomer, this scope is built with simplicity in mind, is constructed by cheap materials and is mainly used for deep sky and planetary observing. Unfortunately we live in a world that money leads the way. But the sky is ours and the dobsonian is a very good way to observe it. Most dobsonians are atm (amateur telescope making) projects and have 3 main parts. The tube, mirror box and rocker box (mount). All parts can be easily made using a hammer and a saw. As for the mirror you can grind one by yourself or buy a readily made one. Of course there are commercially made Dobsonians like the Meade Lightbridge and others..

Yesterday in science.nasa.gov there was an article regarding mirror making using moon dust. Its not hard to think that future generations in moon with no special components will start building dobsonians for their observations..

Of course nothing is perfect and there are some tradebacks. For starters its pretty difficult to motorize this kind of mounting if you want to use it for astrophotography. But there are commercial(expensive) products to make your life easier. Or you can make a DIY project 😉 Also there are issues regarding heavy finderscopes or uncommon eyepieces that will alter balance. There’s a solution to that too by adding counterweight to the rocker box.

This video by truemartian makes a small comparison:

Well.. its not hard to decide which is the most practical enjoyable and easy to transport.

This is considered to be the largest made dobsonian.. A magnification of 1600x has been achieved.. and you can actually make it!!!

Note: There are many good telescopes of any kind type or mounting. The above are just my views of a scope that has some more pros than cons.

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Written by aperturefever

July 10, 2008 at 4:09 pm

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