About the Celestron EdgeHD 8 Optical Tube Assembly...
The EdgeHD is an aplanatic Schmidt Celestron Telescope designed to produce aberration-free images across a wide visual and photographic field of view. The optical system was designed to reduce more than just off-axis star coma, but also to give an astrograph quality flat focal plane all the way to the edge of the field of view.
True Astrograph Quality - Many optical designs that advertise themselves as "astrograph" quality actually only produce pinpoint stars across a curved focal plane. While this may be acceptable for visual observing, stars will appear out of focus at the edge when used with a flat chip sensor of a digital camera. Celestron Telescope EdgeHD optics produce a focal plane more than three-times flatter than a standard Schmidt Cassegrain telescope and dramatically flatter than other competing coma-free designs. This guarantees you visibly sharp stars across some of the largest CCD chips available today.
Improved Performance - Superior edge performance not only creates rounder, more pleasing stars but actually improves the resolution and limiting magnitude when compared to telescopes of equal aperture. Celestron Telescope Starbright XLT Coatings coupled with Celestron'''s StarBright XLT coating group on every surface, EdgeHD optics gives you maximum light throughput across the widest visual and photographic spectrum.
Mechanical Features - In addition to Celestron'''s new optimized optical design, the EdgeHD tube has been redesigned to make sure you get the most from your Celestron Telescope optics each and every night.
Mirror Clutches - Flexible tension clutches hold the mirror in place and reduce image shift when rotating the tube around the mount. The flexible rods allow the Celestron Telescope mirror to be held in place without putting any force or pressure on the mirror assembly, keeping the image centered in the eyepiece (or chip).
Tube Vents - Cooling vents located on the rear cell allow hot air to be released from behind the primary mirror. Each vent has an integrated 60 micron micro-mesh filter guaranteed to let warm air out without letting dust in.
Fastar Versatility - The EdgeHD is the most versatile imaging Celestron Telescope available today. At its native f/10 you can achieve the image scale necessary to capture the smallest of deep sky objects. With the optional reducer lens (coming soon) you can increase your field of view without sacrificing optical performance. A barlow gives you the added power for high resolution planetary, lunar and solar imaging. And of course all EdgeHD optical tubes are Celestron Telescope Fastar compatible for ultra fast f/2 wide field imaging. Each tube has been fitted with a removable secondary mirror and are opto-mechanically aligned on a laser bench to ensure they are axially symmetric in any configuration.
Celestron EdgeHD 8 Optical Tube Assembly Features...
- 8" EdgeHD Optical Tube Assembly
- Aluminum Optical Tube
- Celestron premium StarBright XLT coatings
- 2032 mm focal length (f/10)
- 40 mm eyepiece included (51x)
- Visual back allows for use with 1.25" accessories
- 9x50 finderscope to help accurately find objects
- Star diagonal provides more comfortable viewing position when observing objects that are high in the sky
- Mirror Support Knobs hold the mirror in place and reduces image shift during imaging.
- Tube vents with integrated 60 micron mesh filter allowing hot air to be released from behind the primary mirror.
- Fastar Compatible optical tubes are equipped with a removable secondary mirror for fast f/2 ccd imaging
- Includes dovetail rail compatible with CGE mount
Celestron EdgeHD 8 Optical Tube Assembly Specifications...
Optical Design: EdgeHD
Aperture (mm): 203.2 mm (8 in)
Focal Length (mm): 2032 mm (80 in)
Focal Ratio: f/10
Eyepiece 1 (mm): 40 mm (1.57 in)
Magnification 1: 51 x
Star Diagonal: 1.25
Optical Tube: Aluminum
Highest Useful Magnification: 480 x
Lowest Useful Magnification: 29 x
Limiting Stellar Magnitude: 14
Resolution (Rayleigh): 0.69 arc seconds
Resolution (Dawes): 0.57 arc seconds
Light Gathering Power (Compared to human eye): 843 x
Secondary Mirror Obstruction: 2.7 in (69 mm)
Secondary Mirror Obstruction by Diameter: 34 %
Secondary Mirror Obstruction by Area: 11 %
Optical Coatings: StarBright XLT
Optical Tube Length: 17 in (432 mm)
Optical Tube Weight: 14 lbs (6.35 kg)
Dovetail Compatibility: CGE Mount
Celestron Product Number: 91030-XLT