Back to Basics: Astronomy Unplugged
Michael Purcell
(This article is especially applicable for those of you who are accustomed to the use of digital setting circles or who use the "go to" feature of their computerized mount. The rest of us might just smile knowingly.)
Something good happened to me during our club's recent (April 2001) trip to New Mexico: my SCT died. I had traveled for two days, bringing with me my PC and CCD camera for the purpose of spending my time capturing more images of deep sky objects. Now, before I had taken a single image, my plans were over. What to do? The answer, born of necessity, was a simple one - return to the basics of star hopping.
For me, this required an abrupt change in observing habits. In the 1980's I had star hopped my way through the Messier list using my grandfather's Unitron refractor and an 8-inch Newtonian "Kramerscope". All this changed when I purchased my first SCT and the Uranometria star charts for the specific purpose of CCD imaging. I had not done any significant star hopping since then. Moreover, I had never star hopped using an SCT and had neglected to bring my Tirion star charts with me because I no longer used them.
I began by using the scope setting circles. The scope was already roughly polar aligned, so all I did was to find M42 in Orion and then rotate the Right Ascension indicator to 5h35m, and I was all set. Or so I thought. I quickly (re)learned the hard way the two essential truths about mechanical setting circles: a) the R.A. is always wrong, and b) even in the rare moment when the R.A and Dec. are correct, they are only an approximation. This was adequate during the first night because I was revisiting my favorite Messier objects, which tend to be easy to find. This was most definitely not adequate when I began attempting to find objects from the Caldwell list.
I then abandoned the setting circles in favor of pure star hopping by using my Caldwell card and the Uranometria. This was not always easy because the finder scope inverted the images both vertically and horizontally, and the Uranometria representation of star brightness does not always match what you actually see in the finder. Practice making perfect, I kept at it, found many Caldwell objects, and had a wonderful time in the process.
So, what's the big deal, you say? My point is that it is easy to become dependent on the computerized "go to" capabilities and digital setting circles of modern telescopes. You quickly forget how much fun it is to work your way through a star field. You lose the chance to view extra objects on the way to your primary target. You can also lose familiarity with the constellations and the objects within them.
Does this mean I have given up CCD imaging? Not at all. It does mean that I will work to have a better balance between computerized and manual observing. As you can see, my equipment failure was really a blessing in disguise. It forced me to rediscover the pleasures of unpowered astronomy. Try it for yourself.
