Commercial astronomical telescope optics development has followed a straight tangent for decades now. Focal lengths have shortened while image sizes have grown. Refractive telescopes houses five or even six lenses, making them more and more like over-sized camera optics, driving up manufacturing costs fast. Producing more and more expensive and generic products for smaller and smaller range of enthusiasts does not pay back development.
Several manufacturers can provide pre-fabricated optical parts for very reasonable prices. For a customer they are very attractive, but for the designer they are that sinister oppressive path through a damp dark forest after reading Lovecraft novels – how can anything innovative come out of something as coarse as pre-fabricated parts? Client is demanding the impossible! Or when viewed with a positive attitude, just kicking you forward. Pre-fabricated components design is very attractive and here to stay, so best to make the best of it. Here I design some basic finite conjugate objectives with pre-fabricated parts and see their limitations first-hand.
Originally published 15.5.2014 by Jani Achrén.