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

PRICES

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

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

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