About Deep Sky
To stand beneath a dark, moonless sky is an awesome experience. Thousands of stars can make us feel small indeed. It seems possible to see to infinity, although we cannot reach beyond arm's length. The beauty of the universe defies description.
Turn a telescope on a seemingly empty part of sky and swarms of new stars come into view - and possibly a faint glow of nebulosity. Imagine that the fuzzy patch at the threshold of visibility is really a trillion suns - a galaxy larger than our own, in which our Sun is but a tiny speck. Incomprehensible; yet somehow we try. Seeing that galaxy first-hand, even through a small telescope, is much more inspiring than each photograph in the astronomy books back indoors. Nothing can compare to viewing the universe directly.
Before the late nineteenth century all astronomy - amateur and professional - was visual. Everything depended on skilled use of the eye. Today, however, the professional astronomer rarely looks through the large telescopes at his or her disposal. As photographic film became more sensitive, both professionals and amateurs devoted more time to photography. In the last few decades, the advent of sensitive electronic light detectors (CCD's) diverted professional and even some amateur work further from visual astronomy. Direct viewing - at least of deep-sky objects is now mainly for those interested just in beauty and inspiration.
There are literally thousands of interesting objects, primarily galaxies but also star clusters and nebulae, within reach of amateur telescopes. Most are very faint, hundreds of times fainter than can be seen with the naked eye. However, a telescope with only 6 inches of aperture gathers about 400 times the light of the unaided eye, so these beautiful but dim objects can be brought into view.
The first-time user of a telescope is often disappointed that galaxies and nebulae do not look like the photographs in astronomy books. In some respects, the eye is no match for the camera. The beautiful photos are the result of very long exposures on sensitive film that builds up an image out of light too faint for the eye to see at all. Nevertheless, the human eye is a very sophisticated light detector in its own way, and if used correctly and in combination with a large telescope, such as my own 18 inch Dobsonian, it can reveal a tremendous amount of detail in galaxies, nebulae and clusters.
Personally, I am amateur astronomer with 22 years of observing experience, although I started with visual deep sky in 1992. In the following years I scanned thousands of objects with my 18 inch Dobsonian telescope - sketching a few hundreds of them. So I made pencil sketches from more than 150 galaxies - and I also brought to paper many planetary and galactic nebulae.
Andreas Domenico (November, 2007)