Celestron CGX Equatorial 800 HD Telescopes Whitepaper EdgeHD Optics - Page 18

.Celestron EdgeHD 925 Celestron EdgeHD 925 The spot matrix shows that on-axis images are diffraction limited at all three wavelengths, and remain diffraction-limited over the central 15mm. While blue and red are slightly enlarged, in green light images are fully diffraction-limited over a 38mm image circle. The size of the off-axis blue and red spots remain nicely balanced. On a night of average seeing, stars will display a FWHM of 23µm, comparable in size to the spot pattern at the very edge of a 42mm field. Relative illumination in the EdgeHD 925 is excellent. The central 12mm is completely free of vignetting, while field edges receive 90% relative illumination. For most imaging applications, flat fielding would be optional. For full-field imaging on a tight budget, the EdgeHD 925 is an excellent choice. It offers nearperfect on-axis performance and outstanding images over a full 42mm image circle. 18 I The Celestron EdgeHD