Keywords: telescope optical design optics optician software freeware source code excel visual basic applications java scripts applets cgi borland turbo pascal delphi kylix c++ builder dos windows linux susse redhat astronomy ray trace raytrace raytracing spot diagram aberration seidel third order spherical coma astigmatism distortion chromatism spherochromatism opd optical path diference encircled ensquared fft psf mtf otf optimization optimize global local merit function damped least square dlsq lsq tolerance layout telescope refractor objective doublet achromatic aplanatic cemented broken airspaced fraunhofer steinheil clark triplet christen glass schott hoya hikari ohara sumita corning gost lzos reflector mirror sphere ellipsoid prolate oblate paraboloid hyperboloid toroid mangin one mirror newtonian dob dobson dobsonian two mirror cassegrain gregorian ritchey-chretien dall-kirkham pressmann-camichel schwarzschild three mirror loveday picht catadioptric camera maksutov schmidt baker wright sigler gregory simak rumak relay wright lurie houghton loveday tct tilted brachyt shiefspiegler yolo off-axis stevick stevick-paul brunn kutter buchroeder herschel focal corrector extender reducer flattener plate lens menisc meniscus barlow ross winn bird brixner eyepices huygenian abbe ramsden kellner erfle plössl ploessl könig koenig ortoscopic amateur astronomer telescope maker atm atm's modas jodas eodas ivan krastev oslo zemax sigma vob code v optix optalix lensview winlens asap synopsis raycad opticad optikwerks winlens winspot optec optica opticalc lensview atmos dboptic opus autoray ados kdp roadrunner aberrator test startest grid terebizh ronchi mosby null inverse wire foucault knife edge millues-lacroix sinnott texerau book article magazine journal letters atmj atmlj sky & telescope skywatch amateurastronomy coelum applied optics josa sterne und weltraum starobserver