How to Interpret an Image Histogram

The Histogram

The histogram is probably the most important tool available in any astro-imaging application, both for capturing images and for processing them once captured. For those just starting out in astrophotography, the histogram is also one of the simplest but most frequently misunderstood tools.

In this short guide will explain the histogram; both what it means and how it can help you to make better images.

Observatory Planning and German Equatorial Mounts

I am in the early stages of planning to build a pico-observatory for my imaging gear. My aim is to make it as small as possible in order to save cost and also to make it easy to build and maintain. There are a number of rough guides to building micro-observatories and pico-observatories on the web, but one key consideration seems to be glossed over in all of them. That is how to determine the space needed for the scope and German Equatorial Mount (GEM) to operate without colliding with the floor, walls or roof of the observatory.

As we will see, the calculations are relatively straightforward, but the slightly counter-intuitive nature of GEMs makes it tricky to figure them out from first principles. Following this guide, you can work it all out with a tape measure, paper and pencil and some string (option) in a couple of minutes flat. Read on for the solution.