How to Visually Observe the Caldwell Objects

Abstract

In days gone by the majority of amateur astronomers were visual observers who trained their eyes, brains, and hands to sketch the objects they saw through the eyepiece. The planetary observers trained their eyes to see the finest details glimpsed in multiple brief moments when the atmosphere was steady, whereas the comet and nebulous object observers trained their dark adapted vision. In the era when advanced astronomy was largely the hobby of the wealthy Victorian gentleman a 6- or 8-in. (15 or 20 cm) brass tubed refractor in a substantial domed observatory was often the norm, and a custom built observing chair was always available so the observer could observe in a civilized manner. In this era of CCD imaging, where portable telescopes are very common and observatories are often sheds on wheels, the comfortable observatory seems to have become a thing of the past, especially when a telescope can be controlled robotically in your garden or half way across the world. However, some degree of comfort is still vital for visual observing, as telescope eyepieces can invariably end up in the most inconvenient positions on the coldest and dampest of nights. For example, an f/4.5, 0.4 m Dobsonian will have a tube length similar to its focal length of 1.8 m, necessitating a ladder to reach the highest eyepiece altitudes and some neck-twisting observing positions. Observer discomfort is not good for seeing down to those very faint targets, and if you are a beginner, craning your neck to get to the eyepiece while holding a chart in one hand and a red torch in the other is no fun at all.