|
Telescope Economics ...or one way of measuring optical 'bang for the buck' |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Just for the heck of it, I decided to look at the telescope market to see what large Dobs were available that were greater in aperture than Brutus (Brutus Main Page) and comparable in characteristics (i.e. premium mirror and f/4 or faster focal ratio). I compiled theses scopes' vital statistics-- including the important eyepiece height at zenith and (more important), list price. All were compared in 'bare bones' configurations. The results were intriguing, and gratifying to my wallet. Replacing Brutus with a new commercial scope would cost a cool 15 grand to net an extra 33% light grasp, and spending over $20K would still yield only a 78% increase in light gathering capability. The exercise did show that, with a few outliers (from vendors known to be on the pricey side), large Dobs with premium optics cost roughly the same per square inch of aperture-- regardless of vendor. Intrigued, I broadened the sample to include premium and mass market medium-sized (15" or 16") Dob comparable in size to Frankenscope and Natasha (Natasha Main Page). Not too surprisingly, Frankenscope-- based on a budget-class Meade "Starfinder" Dob-- gave the most 'bang for the buck' of any scope on the list. Somewhat surprisingly, my up-scale scope Natasha proved to yield as much viewing glass per dollar spent as a medium-grade brand like Discovery, and was significantly more cost effective than the comparably-sized Starmaster and Obsession models. I further expanded the exercise to include several small refractors I own. Most paled in comparison to Dobs in terms of 'bang for the buck'. And a semi-premium grade small apo like the Williams Optics 80mm is nearly quadruple the cost per inch of light grasp of any Dob, even before adding in the necessities (tripod, finder, 2" diagonal) to actually use the scope in the field. (I can only imagine how an AstroPhysics or Takahashi refractor would stack up, but 'bang for the buck' is not the point with such scopes.) What does all of this mean? Well, I think it's no
great secret that building your own reflector yields a less expensive and
more customized instrument than buying one of the 'name brands', but the
magnitude of the difference in price was a bit surprising, whether you are
building average or premium scopes.
|
|