Schupmann Telescope CDs & DVDs maps provide maximum clarity and

maps provide maximum clarity and are optimized for use with red light—ideal for nighttime observation

the Duplex Moon Atlas is the ultimate tool for telescopic observers of the Moon‘s surface

deep-sky objects

and NGC 5728

Schupmann Telescope CDs & DVDs maps provide maximum clarity andBy James Daley. Product Information: Hardbound, 6 by 9 inches, 200 pages. Perfecting the refracting telescope has frustrated lens designers and glass makers since the invention of the telescope. This is because when using standard crown and flint glasses, residual longitudinal color (its dominant defect) cannot be reduced to an optically harmless value. Even today, the most expensive special glass apochromats show some noticeable color, especially at