Statistics: The Last Refuge from Cloudy Sky
By Jay Reynolds Freeman

A few months ago, there was a thread on sci.astro.amateur regarding what telescopes get used the most. Every six months or so, I add up running totals of things observed, and enter the data in my logbook. Last time, I took a moment to organize things to answer that question for myself. The results are rather interesting.

The overall data are simple: From 1978, when I started keeping my present kind of records, through the end of 1998, I logged 11133 observations altogether of 4783 different celestial objects. Only 53 of those objects were in the solar system, and of the ones beyond, only 876 were single or multiple stars. The rest were all galaxies, clusters, or nebulae, of one kind or another. These observations were made during 777 setups, a setup being use of one instrument at one place on one night, but that includes 109 occasions on which I made observations -- 150 altogether -- with the naked eye, and 215 occasions in which I observed through someone else's telescope, with a total of 846 observations so made. The remaining 10137 observations were made with a total of 27 different telescopes or binoculars which I either owned or had borrowed for a long period.

The distribution of observations over instruments is skewed. 20 of those 27 instruments were what most call "very small" -- binoculars or telescopes of four inch aperture or less -- but it was with the others that I did the lion's share of the observing. Harvey, my Celestron 14, is the largest telescope on my list, and he was the overall winner, with 2302 observations during 55 setups. My 6-inch Intes Maksutov was runner-up, with 1880 observations in 61 setups. A six-inch hand-held Newtonian was third, with 965 observations in 46 setups, and an 8-inch f/5 Dobson-mounted Newtonian fourth, with 848 observations in 75 setups. Those four telescopes accounted for 5995 observations, or 59 percent of the 10137. Only one "small" telescope yielded more than 500 observations; that was Refractor Red, my 55 mm Vixen fluorite, and only because I did a Herschel-400 survey with it. All binoculars combined provided 908 observations, 9 percent of the total.

I perform a Messier survey with every instrument of reasonable size that I have for long enough, and when I subtract off that observing, the results are more skewed. About 2460 of the observations were for Messier surveys, so subtracting them leaves 7677. Harvey accounts for 2193 observations other than his Messier survey, or 29 percent of the total. The top four telescopes produced 5559 non-Messier-survey observations, or 72 percent of the total. Binoculars accounted for only 363 such observations, less than five percent of 7677.

So the bottom line in my observing habits seems to be that despite the convenience of small equipment, aperture wins: For the most part, I play with very small telescopes, but observe seriously with larger ones. That result is interesting because most people deliver the good advice, that the right telescope for an amateur astronomer to buy is the one that will be used the most, with the additional comment, or at least the implication, that the telescopes that get used the most are small ones. My experience seems rather to indicate the contrary, even up to telescopes as large and -- UNGAWAH!! -- bicep-bulging as a Celestron 14. On the other hand, I suspect I am weirder than most.