D & G is pleased to offer Classical Cassegrain optics and complete tube assemblies. Many Cassegrain telescopes do not perform well because of the high degree of optical quality necessary to achieve diffraction-limited performance. A relatively large central obstruction necessitates the most precise optics for superior resolution. Each set of optics is hand figured, diffraction-limited and quaranteed to equal or exceed the performance of any obtainable at any cost. A working unit is available here in PA for viewing to all interested parties.

Tube Asembly Includes

  • 20" F/15 Classical Cassegrain optical set of fine annealed Pyrex
  • Baffled aluminum tube, 23 ½" O.D., 80" long
  • Tube painted flat black inside, gloss white outside
  • Large rack and pinion focuser as described elsewhere
  • 2" and 1 ¼" adapters
  • 50mm finderscope
  • Dustcovers
  • Diameter of secondary 5"
  • Back focal distance : 9 ½" behind backplate
  • Weight: 158 pounds


20" F/15 Classical Cassegrain Tube Assembly………..$19,990.00

20" F/15 Classical Cassegrain Optic set……..………..$11,990.00

Shipping charges collect

© 2007 D & G Optical
2075 Creek Road - Manheim, PA - 17545
Phone: 717.665.2076 - Fax: 717.665.1850 - Email


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