Coma Free GSO 8" Newtonian F4
- Aperture 200 mm (8") / focal length 800 mm / photographic speed f/4
- High quality parabolic primary mirror with 94% enhanced reflectivity coatings
- Precise 2" Crayford focuser with 1:10 dual speed transmission
- Primary mirror cooling fan and battery case
- 8x50mm Finder Scope and Bracket
- 35mm 2” CNC extension tube
- Tube rings and Vixen style dovetail
- 2” Coma corrector
- Total weight is 28 lbs with Free Shipping in US mainland only
Basic Manual for Focuser Adjustment & Optical Alignment
The Advantages of Newtonian:
The Newtonian telescopes are free of chromatic aberration found in refracting telescopes. They are usually less expensive for any given objective diameter (or aperture) than comparable quality telescopes of other types. A short focal ratio can be more easily obtained, leading to wider field of view.
The difference between Newtonian and Dobsonian:
Basically, the optical performance on Newtonian and Dobsonian is almost the same; however, the design of backfocus between them is quite different. The backfocus is much longer on Newtonian for astrograph. Briefly, Newtonian was originally designed for the purpose of photography. Besides, we recommend users should seriously consider about the coma free design if you are going to take photo of deep sky with Newtonian.
Coma Free Optics
This big GSO Newtonian reflector features a 8" (203mm) diameter parabolic primary mirror with 94%-96% reflectivity. Coma is an inherent property of telescopes using parabolic mirrors. This results in an image that is not in the center of the field looking wedge-shaped. This causes stars to appear to have a cometary coma in traditional Newtonian reflector.
Built in GSO Coma Corrector is optimized by 3 elements fully coated lens, providing pinpoint stars to the edge of the field with no increase in magnification. We pursue the optical performance beyond everything. We provide the excellent optical performance with affordable price.
Why do you purchase Newtonian from GSO ?
You would be confused about which brand of Newtonian is most valuable in current market. GSO would be one of the best choices. Actually, GSO manufactures lot of Newtonian for Orion, Meade and other brands every year. Why does Meade still ask GSO to provide them telescope, such as light bridge? GSO is famous for the quality of their optics, and are generally better than the Chinese standard. GSO provides customers the professional Ritchey-Chrétien optics these years successfully, the manufactures of parabolic mirror became almost piece of cake for them. Every parabolic primary mirror was polished and corrected perfectly under the inspection of Zygo interferometer.
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