ED APO FPL-53 Series
The ED APO FPL-53 Series represents the most advanced refractor design currently available from Explore Scientific. These instruments feature FPL-53 glass that is is manufactured by Ohara in Japan. These FPL-53 ED Carbon Fiber Series Apochromatic high-performance astrograph refractors designed to take your astrophotography to the next level.Apochromatic (ED APO) lenses are designed to bring three widely separated wavelengths into focus in the same plane where as Achromatic lenses are corrected to bring two wavelengths into focus in the same plane. FCD-100 is manufactured by Hoya in Japan and has a lower refractive index than the FCD-1 used in the FCD1 series telescopes. This results in better color correction, contrast, and image sharpness at higher magnifications.
Chromatic aberration is the phenomenon of different colors focusing at different distances from a lens. Telescope objective lenses for wide-band digital imaging in astronomy must have apochromatic correction, as the optical sensitivity of typical CCD imaging arrays can extend from the ultraviolet through the visible spectrum and into the near infrared wavelength range. Apochromatic designs require optical glasses with special dispersive properties to achieve three color crossings. Explore Scientific achieves this using costly ED (Extra-Low Dispersion) glass.