10-minute Video of Telescopes: www.youtube.com/watch?v=Qnrjve2AEhY Click "Show More" for more information... Pictures of Telescopes: imgur.com/a/HkQvK#0 For Sale: Rare research grade 12" f12.2 achromatic refractor of superb optical quality together with companion telescopes. This large refractor, which took over a decade to complete, is capable of long exposure astrophotography. It was custom manufactured by D&G Optical and rides on a unique, accurate, and rigid Byers Series III mounting and pier. This extremely beautiful cluster of telescopes (large refractors that are reminiscent of the old Alvin Clark and Unitron telescopes that we dreamed of in our youth) is excellent for solar, lunar, planetary, globular cluster, planetary nebula, etc. viewing. This custom-made instrument and its auxiliary telescopes possess many important features, including the following: • This telescope was featured in the February 2013 issue of Sky & Telescope (pages 66-69) o 12" Achromatic objective lens made to very high standards by D&G Optical from proprietary crown & flint glasses that are fully multicoated o Oversized 14" powder coated tube designed for superior cooling and thermal properties o Extra flat black interior baffles minimize internal reflections & ensure a velvety black background to the image o Custom 24" x 16" dia. dew cap is fitted with a heater & adapter that accepts various aperture stops and filters o Custom-made, extremely accurate, heavy duty Byers 2" focuser of double helix design o Rigid stainless steel yacht steering wheel (custom machined onto the eyepiece end of this large refractor by Edward R. Byers Co.) makes slewing the telescope easy • Includes a cluster of 4 auxiliary telescopes (plus a finder) specifically made for solar observing o Two custom 5" f/30 achromatic refractors in oversized tubes by D&G Optical o Two 3" f/30 singlet refractors (with internal fans to promote laminar air flow)custom made for full disk solar observing in H-alpha and Ca-K by the late Bob Mortimer • Custom hexagonal tube rings with collimation adjustments by Edward R. Byers Co. rigidly support the 12" refractor and auxiliary telescopes—and enable them to be accurately aligned • These telescopes ride on a unique, custom-made Byers Series III mounting made by Edward R. Byers Co. o The electronics provide accurate solar, lunar, and sidereal tracking rates o This mount has 5" diameter bearings at the top of both the polar and declination axes o Both axes are driven by large worm gears that are diamond lapped for maximum tracking accuracy o Highly accurate drive gear on polar axis is 18 ½" diameter with 584 teeth o Highly accurate drive gear on declination axis is 15" diameter with 480 teeth o Both drive gears have worms that are spring loaded to eliminate backlash o The drives use DC servo motors—which have a greater speed range, more power, and are smoother than stepping motors o This telescope includes 2 rigid steel piers of different heights custom made for the Series III mounting by Edward R. Byers Co., each having its own storage compartment o A unique feature of this mounting is that it has both traditional analog setting circles and digital readouts for right ascension and declination • Ed Byers states that his company will no longer be making analog setting circles o The highly accurate 18 ½" right ascension setting circle is unusual for having its own electronic sidereal drive system that keeps in synchronized with the sky o Once this setting circle is initialized at the beginning of an observing session, the scope can then be pointed to any object by dialing in the RA directly on the circle o Thus, one does not need to worry about making hour-angle calculations or having the setting circle lose accuracy when the telescope is slewed o The digital setting circles are initialized by using any of 6 bright stars, 3 of which are above the horizon at any given time All reasonable offers will be considered. Please contact the owner, Ed Noffsinger, either by e-mail (TheDIGMAmodel@aol.com) or by his home phone in California (831-427-1011).

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