Monthly Archives: October 2017
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A Guide to Imaging Filters
Figure 1-1: A multi-panel image of the Orion and Horsehead Nebulae. The images are a composite of separate images taken with an H-alpha line filter and red (R), green (B), and blue (B) color imaging filters. The H-alpha image was taken from a large urban location near Toronto, Canada. Credit:
Adam Evans/Flickr.
1. Overview
Thanks to continuous advances in semiconductor technology and image processing techniques, amateur astronomers now have at their disposal camera technology that rivals what was available to professional astronomers less than twenty years ago. Compared to the old days of film astrophotography, modern digital astronomy cameras and DSLRs are extremely sensitive and relatively easy to use,
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Choosing a Non-magnifying Finder for Your Telescope
1. Overview
Other than an eyepiece and a good star chart, no other accessory is as important to a stargazer as a finder. That's because most telescopes, even with a low-power eyepiece, show you a very small slice of sky, often less than one degree wide, which makes it very difficult to point the scope quickly and accurately at even a bright target like the Moon or Jupiter. To help you find your way around the sky, many telescopes come with a finder scope, a small telescope with a wide field of view mounted on the main tube and aimed in the same direction as the main scope. But many stargazers rely on another type of finder, a non-magnifying or unit-power finder to quickly and easily find their way around the sky.This article takes you through the pros and cons of non-magnifying finders so you can decide if they are right for you.
2. How
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