Thursday 3 July 2014

More about starting out.

The Maksutov-Cassegrain telescope design has basically the same advantages and disadvantages as the Schmidt. It uses a thick meniscus-correcting lens with a strong curvature and a secondary mirror that is usually an aluminized spot on the corrector. The Maksutov secondary mirror is typically smaller than the Schmidt's giving it slightly better resolution for planetary observing.

However, the Maksutov is heavier than the Schmidt and because of the thick correcting lens, it takes a long time to reach thermal stability at night in larger apertures. The Maksutov optical design typically is easier to make but requires more material for the corrector lens than the Schmidt Cassegrain.




Telescope Mountings

Now that you have learned about aperture, power and the different types of telescopes, let us discuss an often overlooked but very important aspect of using a telescope - the mountings. Remember that shaky view is all it takes to kill your enthusiasm! And a good mount can enhance your views. There are two basic telescope mountings:

    * The equatorial and
    * The altazimuth.

An Equatorial mount is designed so you can easily track the motion of the sky as the Earth turns and its motions indicate celestial north south and east west in the eyepiece. This is a great help when you're trying to find your way among the stars with a map. The Altazimuth mounts are simpler and just swing up, down, left and right. You have to move the scope along every so often to follow the stars, moons and planets. An altazimuth mount is both cheaper and lighter for the same degree of stability, advantages that are offered by an equatorial mount design.





You and your telescope

Whichever telescope you pick, choose one that will meet your precise needs and hobbies. The planets, the Moon, and close stars require high power, good contrast, and sharp resolution, and if these are the objects of your attention, a refractor or reflector is probably the best bet. While very faint objects like galaxies and nebulae need a huge aperture and you should invest in a big reflector telescope to view these. And if you haven't specialized, an all-purpose midrange telescope should serve best, for example a 6" or 8" reflector or an 8" Schmidt-Cassegrain.

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