Celestron 9.25" EdgeHD optical tube, CGE/Losmandy dovetail


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The EdgeHD high definition flat field optics of this Celestron 9.25" EdgeHD optical tube give you true astrographic-quality 9.25" optics with a definite edge over other reduced coma optical systems . . .
Our Product #: C9HDOTA
Celestron Product #: 91040-XLT
Recommended Accessories

Product Description

This Celestron EdgeHD 9.25 optical tube has:
• 9.25" EdgeHD Faster-compatible high definition aplanatic Schmidt-Cassegrain optics
• StarBright XLT optical multicoatings for the highest possible light transmission
• mirror locks and cooling vents
• 9 x 50mm finderscope in quick-release bracket
• 2" star diagonal
• ultra-premium 23mm 82° field 2" Axiom eyepiece (102x)
• CGE (Losmandy-style "D-plate") dovetail
• 2-year warranty

The compact and easily transportable Celestron 9.25" EdgeHD optical tube has new and unique 9.25" aperture aplanatic (free from coma and corrected for spherical aberration) EdgeHD high definition/high contrast Schmidt optics. The advanced EdgeHD optical system uses a dedicated dual-element field flattener lens made from premium Schott optical glass in its central baffle tube to reduce off-axis coma and produce aberration-free images across a wide 42mm image circle (as large as the diagonal of a 35mm negative or large format CCD chip and ideal for astrophotography).

In addition to reduced off-axis coma, the EdgeHD optics deliver an astrograph-quality focal plane more than three times flatter than standard Schmidt-Cassegrains and dramatically flatter than competing coma-free designs. Stars are smaller and more concentrated, creating brighter images and allowing you to see down to a fainter magnitude than other equally-sized telescopes. With EdgeHD optics, you see sharp point-like stars to the very edges of some of the largest CCD and DSLR chips available today.

For the ultimate in brightness and contrast, the 9.25" EdgeHD optical tube has state-of-the-art Starbright XLT multicoatings. Its light grasp is more than 1100 times that of even the sharpest dark-adapted eye, revealing to your eye and camera star clusters, nebulas, planets, and galaxies in amazing detail. The Fastar-compatible optical tube even allows imaging down to an incredibly-fast f/2 focal ratio using optional accessories.

This Celestron Optical Tube's Optics . . .

EdgeHD aplanatic Schmidt-Cassegrain optics: 9.25" aperture (2350mm focal length f/10). Guaranteed diffraction-limited optical performance, free from coma and corrected for spherical aberrations (aplanatic design). Dual-element field flattener lens built into central baffle tube. The 22" long aluminum optical tube has a large handle on the rear cell and weighs only 20 pounds, making it easy to transport and assemble the optical tube to a mount in the field. For more details, click on the "EdgeHD optics" link in the support tab above.

Starbright XLT fully multicoated optics: This high transmission/high reflectivity optical coatings package applied to each optical surface gives you visibly higher light transmission for brighter deep space images and shorter exposure times during imaging. It also increases the contrast on subtle lunar, planetary, and nebula details when compared with optics using ordinary coatings or multicoatings. For more details, click on the "Starbright XLT" link in the support tab above.

Fastar compatible: For the ultimate in wide-field catadioptric imaging, the EdgeHD optical tube is Fastar compatible to allow CCD imaging at a blazingly-fast f/2 focal ratio. For f/2 imaging, an optional Fastar lens assembly lens replaces the scope's removable secondary mirror (an exchange that takes only a few minutes). Your CCD camera is attached to the Fastar lens. This puts your camera at the f/2 position in the center of the Schmidt corrector lens at the front of the optical tube, rather than in its normal f/10 position at the Cassegrain focus at the rear. The Fastar option is for imaging only and cannot be used for visual observing.

This Celestron Optical Tube's Mechanics . . .

Focusing: Focusing is accomplished by turning a knob on the rear cell that moves the primary mirror fore and aft along the central baffle tube to adjust the focus. The Celestron focusing mechanism is supported by two pre-loaded ball bearings, minimizing the "mirror flop" typical of bushing-type focus mechanisms that causes image shift during critical focusing.

Mirror locks: Flexible tension locks hold the mirror in place after correct focus is achieved for imaging and reduce image shift when rotating the tube around a mount (when moving past the zenith during astrophotography, for example). Unlike other designs that have only one locking knob located off to one side of the mirror, the Celestron system uses three locks equally spaced around the mirror to distribute the mirror locking force symmetrically.

The focuser itself acts as one of the locks, while two flexible rods spaced 120° away in either direction act as the second and third locks. Controlled by variable tension knobs on the rear cell, these rods act in conjunction with the focuser to hold the mirror in place without putting any asymmetrical force or pressure on the mirror. This keeps the image centered in the eyepiece (or chip) no matter what the orientation of the optical tube.

Tube vents: Two cooling vents on the rear cell allow warm air to be released from behind the primary mirror when the scope is taken out for a night's observing or imaging. This shortens the amount of time needed for the optics to cool down to ambient air temperature for peak performance. Each vent has an integrated 60 micron micro-mesh filter guaranteed to let warm air out without letting dust in.

Dovetail rail: The full length dovetail rail mounted under the optical tube fits Celestron CGEM, CGE, and CGE Pro mounts, as well as any other make or model German equatorial mount that uses a Losmandy-style "D-plate" mounting dovetail slot.
This Celestron Optical Tube's Supplied Accessories . . .

Finderscope: The supplied 9 x 50mm straight-through achromatic design finderscope has a wide 5.8 degree field of view. It is mounted in a spring-loaded easy-adjust quick release bracket.

Star diagonal: The supplied star diagonal is a 2" first surface mirror. Also included is a 1.25" visual back.

Eyepiece: The standard equipment eyepiece is a premium 2" 23mm 82° field Axiom (102x). The eyepiece field of view is 0.8° wide, over 50% larger than the full Moon, and an exceptionally wide field for the 102x magnification.

Two-year warranty: All Celestron optical tubes have a two-year warranty.

Tech Details

Aperture 9.25"
Focal Length 2350mm
Focal Ratio f/10
Highest Useful Magnification 470x
Weight 20 lbs.
Resolution 0.49 arc seconds
Visual Limiting Magnitude 14.4
Warranty 2 years


Review by:
I bought this OTA about years ago and never regretted it once. It's outperformed all my other telescopes for both visual and AP over the years and it's always a big hit at star parties. It's heavy and you really need a solid mount, especially when you begin adding things to it. Even so, it's a worthwhile purchase and will do anything I want it to do aside from dispersing clouds. (Posted on 10/4/2019)
Review by:
I use this scope on a SkyWatcher EQ6-R Pro GEM for AP. The 2350mm FL is perfect for imaging galaxies. globulars, and other DSOs that need some reach, and I've been able to get nice round stars "all the way to the edge." To avoid vignetting when imaging with a full frame DSLR, I replaced the stock adapter with the Celestron Large Adapter for OAG. For wider field targets, I hope to stitch together mosaics, and when budget allows, add the 0.7 focal reducer. (Posted on 7/23/2019)
Review by:
When I first received this scope, I set it up on a street corner in a suburb of Memphis, TN just to check it out. With a major light dome always present at this location I wasn't expecting much; just wanted to dial it in by catching a couple of planets. With an Explore Scientific 2" 18 mm eyepiece, Saturn and Jupiter were exceptional, even through the haze. I was soon joined by neighbors and passers-by who experienced the typical "Wow" factor. From then on, I was the main attraction every night I hauled the 9.25 out. It does collect moisture, but the passive dew shield from Celestron has so far kept it clear if you aren't too near the zenith.

Unfortunately, I was a victim of my own age and infirmities and dropped this beautiful instrument, breaking the corrector plate among other indignities. When the budget allows, I will definitely replace this scope. It's a keeper. (Posted on 10/16/2018)
Review by:
I use mainly visually, with a 17mm Nagler that almost never comes out. This combo gives 138x magnification and 36 arcmin FOV, which for average skies and the majority of targets gives bright crisp views. When seeing is above average, I pop in a 10mm Delos, giving excellent views of globular clusters (one of my guilty pleasures). When collimation is tight, great views of the planets and moon! I really enjoy the Dumbell Nebula and Orion's Nebula core with this combination.
I have not imaged much with the scope yet, but on the few occasions I have, a very flat FOV is produced with very little coma at the edges (must be pixel peeping to notice).
The inclusion of a Losmandy style dovetail plate was a nice feature and makes for a solid connection with very little flexure on my Paramount MyT. And for a stock focuser, I have been very impressed...not disappointed enough to upgrade.
If the scope would hold collimation more consistently, I would have given 5 stars, as it seems very sensitive to temperature. Not a deal breaker, and the scope is easy to collimate.
(Posted on 10/7/2018)
Review by:
I bought the 9.25 Edge HD ota for imaging. The optics are flat across the entire field out to the edge. The OTA is very light and easy to carry even with my guidescope on top. This size is the best weight for most medium size mounts. Especially when imaging. The 2350mm focal length is perfect for imaging galaxies and star clusters. The focuser is smooth with very little image shift and the mirror locks prevent mirror flop when crossing the meridian. One of the most important features is that it's Fastar capable. With an optional Fastar lense you can image widefield at F/2. Theres even a nice big handle to carry it with. The 9.25 235mm size lets in plenty of light for imaging and visual use.
Neilson (Posted on 8/4/2017)
Review by:
I have only used this visually... but, so far the views have been impressive. Saturn, Jupiter and the moon have looked great through this scope. On DSO's I've also been impressed with how bright galaxies, planetary nebulae and globular clusters have been in this f/10 optic. My intentions were to use this for AP but have not had the chance yet, but if it's as good as it has been visually, I'll be very happy. The only reason I'm not giving 5/5 stars is for the focuser which is somewhat sloppy for the price. I'm considering upgrading this feature. (Posted on 8/4/2017)
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Supplied Accessories

  • Starbright XLT fully multicoated 9.25" f/10 Fastar-compatible EdgeHD optics
  • 9 x 50mm finderscope
  • 2" star diagonal with 1.25" visual back
  • 2" 23mm Axiom eyepiece (102x)
  • Dust covers
  • CGE (Losmandy-style "D-plate") dovetail mounting rail.