For as long as man has gazed up at the skies there has been a fascination with the stars. In the early days of astronomy, there was no distinction between amateurs and professionals. Today, astronomy is a very complex and technical pursuit, yet many of us are compelled to investigate the wonders of the Universe. Because there is so much to the science of astronomy, amateurs can pursue a varied set of courses to their end. In my case, I am interested in the far distant “fuzzies” in the sky, which are usually referred to as DSOs or Deep Sky Objects. DSOs include galaxies, star clusters, and nebulae. My approach to observing these wonders is to photograph them.
Not having access to the clear dark skies of a mountain top where the major observatories are located, amateurs around here must work around our light-polluted skies. This is accomplished using telescopes that are modest in size, but which are augmented by modern electronic imagers. It is these digital “cameras” that make it possible to take long exposures from our backyards, resulting in images only available from major instruments just 20 years ago. There is an enormous satisfaction in imaging a galaxy, cluster or nebula whose light started its journey millions and millions of years ago.
The instruments we amateurs use vary in size from ordinary digital cameras with wide angle lenses to large apertures up to 20” or more in diameter. Many visual observers use the simplest of mounts with no tracking or electronic aids.
Imaging systems for DSOs have more stringent requirements. Mounts that track the movements of the stars and include “goto” computers, which can point the telescope to any of thousands of stars, planets, and DSOs, are commonly used. The imaging electronics may be a simple point-and-shoot digital camera, a regular DSLR (digital single lens reflex), or a special cooled CCD camera that has very low noise and high sensitivity.
The images of DSOs are usually created by taking many relatively short exposures ranging from 30 seconds to ten or more minutes. Overall exposures from 20 to 30 minutes up to several hours are created by combining multiple images using specialized computer programs. These techniques reduce noise and light pollution effects and reduce the necessity for mounts that can keep an image accurately centered for several hours. All this technology has become available to amateurs over the past 15 to 20 years.
My journey in astronomy began in high school. My first telescope was an inexpensive 2″ refractor on a simple alt/az mount. Not much beyond a few planets and the moon were visible. During my college years, I ground and polished a 6” mirror for a Newtonian telescope. This was to be put away for many years and only recently did I actually complete the scope.
My next scope was an 8” SCT (Schmidt-Cassegrain) on an equatorial mount with motorized tracking and an object-finding computer. This created the ability to visually observe much more. I did take a few images with this scope, mainly of the moon.
Over the last several years I upgraded my equipment to a 5” refractor on a precision equatorial mount. The mount have been augmented with active guiding that allows very long exposures with computer control. My camera is a dedicated CCD with electronic cooling.
Many long nights have been dedicated to acquiring the images and lots more hours have been spent in processing the many sub-frames into the final images shown. The resulting images certainly do not rival those captured by Hubble or any of the large telescopes professionals use, but the personalization of the process yields an intimate connection to astronomy and the objects imaged that no textbook can supply. Seeing and imaging the real thing is the best way to gain an appreciation for the extent and majesty of this Universe in which we live. There is nothing like having experienced a Lunar eclipse in 13 degree weather (February 2008) to give one an appreciation for the science of astronomy.
My future plans include imaging all of the 110 Messier catalog objects. I am about halfway there as of now. This is a hobby of the pursuit of perfection. There is lots of challenge and there are more than enough objects out there to last a lifetime. Hopefully the images presented here and my experience will inspire other aspiring amateurs to start imaging and experience the thrill of seeing their first DSO appear on the computer screen.
My Astronomy 