Focus on challenging optical components

Yet Another 'Buying Your First Scope' Guide

by:ChangHui     2020-04-15
Before I begin yet more suggestions on what things to buy, here are a few points which could potentially save you some disappointments later on: Magnification matters. To see the gap between rings of Saturn, you need at least three-hundred to four-hundred times magnification. But the thing to remember is that magnification factor is dependent upon eyepiece, and not upon the telescope itself. Therefore, telescopes known as 'department store telescopes', which advertize 'magnification 500 x telescopes', are not to be trusted. At the same time, every telescope has its maximal useful magnification, which is dependent on the diameter of the telescope and its construction, and which basically indicates the most powerful eyepiece that can reasonably be inserted into telescope. More magnification, and you just get fuzzier picture. For 8 inch (20 cm) diameter Schmidt-Cassegrain, maximum magnification is about 450 times. For those who wish to calculate magnification factor of an eyepiece/telescope, the combination is calculated as the focal length of the telescope divided by the focal length of the eyepiece. These numbers are usually written on eyepieces and telescopes.You WILL see a great deal more stars than even through binoculars. So much more, in fact, that it becomes really tricky to find your bearings. Add to that different radii of different eyepieces, and you have an instant recipe for stress. Your new telescope will quickly transform into a really expensive dust collector.You will NOT see shiny blue or red nebulae through telescope. In the best of circumstances, you will see grey clouds with hints of structure. This is true for both emission and reflection nebulae. Even brightest ones, such as Dumbell Nebula or Ring Nebula have color only on photographs. Galaxies are even worse. They are large and scattered and really hard to see. Especially from light polluted areas. This is due to the fact, that color receptors in our eyes are much less sensitive than the receptors that detect light (i.e. black and white). To view colors, you'll need to collect lots more photons to your eyes, and for that you would need telescope the size of the Keck telescope on Mauna Kea, Hawaii. Not your average beginners telescope, by any standard. Developing from the bottom up Astronomy gear is similar to house building - you will need a reliable foundation if you don't want your skyrise apartment to collapse or be wobbly in the lightest wind. And the foundation of the telescope is called mount with tripod. The tripod holds all of the gear on it; for that reason, it must be sturdy and quite heavy. Experienced users, who have a permanent arrangement built for their telescope, prefer to replace the tripod with a solid concrete pier. This is how robust and firm an ideal tripod should be. In any case, you will wish to have the tripod that doesn't vibrate very long after you tap it or stumble on it. Because, believe me, you will stumble on tripod. Tripod normally holds the mount. Mount is the gadget that moves the telescope's optical tube. It has to move it smoothly. If you want to see a crater on the Moon, that is currently at the edge of your field of view, and, because of poor mount mechanism, you jerk the telescope half way across the sky, the desire to discover secrets of the night skies will dwindle very quickly. The mount also needs to be firm. If you point it to a particular star, you don't want your telescope turning to the lawn all by itself.
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