Celestron’s EdgeHD telescopes represent a major advancement on both the optical and mechanical features of their renowned Schmidt-Cassegrain telescopes.

Optical Features

From an optical point of view, EdgeHD is an aplanatic flat-field Schmidt optical system developed to produce aberration-free images with pinpoint stars all the way to the edge of the field of view of today’s largest imaging sensors and wide field eyepieces. The EdgeHD optics virtually eliminates both field curvature and off-axis star coma, providing an astrograph-quality system at a fraction of the price of competitors. EdgeHD optical tubes are sold separately or paired with our most popular telescope mounts.

Many current optical designs advertise themselves as “astrographs,” but only produce pinpoint stars across a curved focal plane. This means that when focused sharply in the centre of the field of view, this curved plane cannot bring stars at the edges into focus and the more pronounced this defect becomes with a wider the field of view. Although this may be acceptable for visual observing, when a curved plane is paired with the flat sensor of a digital camera, stars become noticeably out of focus towards the edges.

Celestron’s 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, guaranteeing you visibly sharp stars all the way across the imaging sensor.

 

Curved Focal Plane

Curved Focal Plane

A curved focal plane cannot produce consistent results on a flat CCD chip. Stars will appear out of focus at the edges.

Now, if you compare the two images of M3 below. The first was taken with a competing coma-free optical design, the second with EdgeHD. Both images were taken with the same 35 mm chip (42 mm diameter focal plane) camera under the same conditions.

When focused on-axis, both images appear to be sharp in the centre. But in the first image, as you examine the stars closer and closer to the edge, the stars become larger and less focused. Finally, at the very corners, the stars are so de-focused that they appear as rings instead of pinpoints.

The competing coma-free design, when focused on the axis, shows sharp stars in the center of the image, but dramatically out-of-focus stars (rings or donuts) at the edges.

The competing coma-free design, when focused on the axis, shows sharp stars in the center of the image, but dramatically out-of-focus stars (rings or donuts) at the edges.

Now look at the second image. As you move from the centre outward, the stars retain their focus from edge to edge, appearing as crisp, solid points of light.

EdgeHD produces a consistent, sharp focus across the entire FOV.

EdgeHD produces a consistent, sharp focus across the entire FOV.

Superior edge performance not only creates rounder, more pleasing stars, but actually improves the resolution and limiting magnitude compared to telescopes of equal aperture.

Celestron’s high definition optics let you resolve smaller spot sizes all the way to the outer edge, revealing finer detail and greater contrast. Compare the two cropped images below, both taken with a 37 mm chip (52 mm diameter focal plane) camera.

Fig. 1 (left): The off-axis coma inherent in many optical designs (such as the SCT shown above) distorts star images and compromises resolution. Fig. 2 (right): EdgeHD focuses sharply across the entire FOV, revealing fine detail lost with other systems.

(left): The off-axis coma inherent in many optical designs (such as the SCT shown above) distorts star images and compromises resolution.
(right): EdgeHD focuses sharply across the entire FOV, revealing fine detail lost with other systems.

What’s more, EdgeHD optics give you smaller, more concentrated stars so you can see fainter magnitudes than with other equally-sized telescopes. Poor edge quality can spread out starlight so much that the brightness of a star appears the same as the sky background, making it undetectable to your eye or camera. With EdgeHD optics, you can capture the faintest of galaxies all the way to the corner of your full-frame camera chip. Compare the two cropped images below, both taken with a 37 mm chip (52 mm diameter focal plane) camera.

Fig. 1 (left): In telescopes that exhibit off-axis coma, faint starlight can go unnoticed at the edge of the field of view. Fig. 2 (right): EdgeHD optics resolve faint detail missed in telescopes of equal aperture.

Fig. 1 (left): In telescopes that exhibit off-axis coma, faint starlight can go unnoticed at the edge of the field of view.
Fig. 2 (right): EdgeHD optics resolve faint detail missed in telescopes of equal aperture.

All EdgeHD optical tubes also feature Celestron’s StarBright XLT coating system on all mirror and lens surfaces. When added to the EdgeHD optical system, StarBright XLT provides maximum light throughput across the widest visual and photographic spectrum. Learn more about StarBright XLT.

 

Mechanical Features

The Celestron EdgeHD tube features innovative mechanical designs to ensure you get the most from your optics each and every night you use the telescope whether it is for visual or imaging purposes.

  • Mirror support: Flexible tension clutches hold the primary mirror in place and reduce image shift. The flexible rods hold the mirror in place without putting any force or pressure on the mirror assembly, keeping your target 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 micromesh filter guaranteed to let warm air out without letting dust in.
  • Fastar versatility: EdgeHD is the most versatile imaging telescope available today. At its native f/10, you can achieve the image scale necessary to capture the smallest of deep-sky objects. To increase your field of view without sacrificing performance, add the optional EdgeHD reducer lens. Each one is custom-made for your size EdgeHD optical tube and brings your focal ratio down to f/7. A Barlow lens provides additional magnification for high-resolution planetary, lunar, and solar imaging. And, of course, all EdgeHD optical tubes are Fastar-compatible for ultra-fast f/2 wide field imaging. Each EdgeHD tube is fitted with a removable secondary mirror and is opto-mechanically aligned on a laser bench to ensure it is axially symmetric in any configuration.
  • Easy collimation: Guarantee ideal performance every time. Edge HD’s precision-machined mechanics and a spherical secondary mirror make collimation simple and accurate.

If you want the full story behind Celestron’s EdgeHD optics, the Celestron’s Product Development team has released a whitepaper outlining the development of EdgeHD, the manufacturing and QA process, and how to get the most out of your system.  It also includes cross-sections of the EdgeHD series, comparative spot diagrams for the EdgeHD and competing “coma-free” Schmidt-Cassegrain designs, a table with specifications for visual and imaging, and graphics showing how to place sensors at the optimum back-focus distance for astroimaging.

Download a PDF of the EdgeHD Whitepaper here.

Products with EdgeHD

Celestron CGX Equatorial 1100 HD TelescopeOut Of Stock

Celestron CGX Equatorial 1100 HD Telescope

£5,750.00
  • Celestron EdgeHD 11” HD aperture
  • CGX computerised equatorial mount
  • Celestron’s premium StarBright XLT coatings provide maximum light transmission
  • A 9×50 finderscope, 2” mirror diagonal for more comfortable viewing, and 2” 23mm wide angle Luminos eyepiece included
Celestron CGX Equatorial 800 HD TelescopeOut Of Stock

Celestron CGX Equatorial 800 HD Telescope

£3,525.00
  • Celestron EdgeHD 8” HD aperture
  • CGX computerised equatorial mount
  • Celestron’s premium StarBright XLT coatings provide maximum light transmission
  • A 9×50 finderscope, 1.25” mirror diagonal for more comfortable viewing, and 1.25” 40 mm Plössl eyepiece are all included
Celestron CGX Equatorial 925 HD TelescopeOut Of Stock

Celestron CGX Equatorial 925 HD Telescope

£4,699.00
  • Celestron EdgeHD 9.25” HD aperture
  • CGX computerised equatorial mount
  • Celestron’s premium StarBright XLT coatings provide maximum light transmission
  • A 9×50 finderscope, 2” mirror diagonal for more comfortable viewing, and 2” 23mm wide angle Luminos eyepiece included
Celestron CGX-L Equatorial 1100 HD TelescopeOut Of Stock

Celestron CGX-L Equatorial 1100 HD Telescope

£7,049.00
  • Celestron 11″ EdgeHD and CGX-L computerised equatorial mount package
  • Celestron EdgeHD 11” HD aperture telescope
  • Celestron’s premium StarBright XLT coatings provide maximum light transmission
  • A 9×50 finderscope, 2” mirror diagonal for more comfortable viewing, and 2” 23mm wide angle Luminos eyepiece included
  • Exceptional 34kg/75 lb load capacity CGX-L mount.
  • Larger 144 mm diameter worm wheels to better and more accurately drive heavier loads
  • Longer 270 mm dovetail saddle to better support larger optical tubes
  • Massive 70mm/2.75″  stainless steel tripod legs with a wider stance for improved stability under heavy loads
  • Spring-loaded brass worm wheel and stainless steel worm gear reduce friction and provide optimum gear mesh
  • Internal cabling for worry-free remote operation. Power input and lower accessory ports remain stationary while the mount slews to avoid snags
  • Includes Celestron’s new PWI telescope control software featuring multi-point mount modelling for extremely precise pointing accuracy
Celestron CGX-L Equatorial 1400 HD TelescopeOut Of Stock

Celestron CGX-L Equatorial 1400 HD Telescope

£11,750.00
  • Celestron 14″ EdgeHD and CGX-L computerised equatorial mount package
  • Celestron EdgeHD 14” HD aperture telescope
  • Celestron’s premium StarBright XLT coatings provide maximum light transmission
  • A 9×50 finderscope, 2” mirror diagonal for more comfortable viewing, and 2” 23mm wide angle Luminos eyepiece included
  • Exceptional 34kg/75 lb load capacity CGX-L mount.
  • Larger 144 mm diameter worm wheels to better and more accurately drive heavier loads
  • Longer 270 mm dovetail saddle to better support larger optical tubes
  • Massive 70mm/2.75″  stainless steel tripod legs with a wider stance for improved stability under heavy loads
  • Spring-loaded brass worm wheel and stainless steel worm gear reduce friction and provide optimum gear mesh
  • Internal cabling for worry-free remote operation. Power input and lower accessory ports remain stationary while the mount slews to avoid snags
  • Includes Celestron’s new PWI telescope control software featuring multi-point mount modelling for extremely precise pointing accuracy
Celestron CGX-L Equatorial 925 HD Telescope

Celestron CGX-L Equatorial 925 HD Telescope

£5,999.00
  • Celestron 9.25″ EdgeHD and CGX-L computerised equatorial mount package
  • Celestron EdgeHD 9.25” HD aperture telescope
  • Celestron’s premium StarBright XLT coatings provide maximum light transmission
  • A 9×50 finderscope, 2” mirror diagonal for more comfortable viewing, and 2” 23mm wide angle Luminos eyepiece included
  • Exceptional 34kg/75 lb load capacity CGX-L mount.
  • Larger 144 mm diameter worm wheels to better and more accurately drive heavier loads
  • Longer 270 mm dovetail saddle to better support larger optical tubes
  • Massive 70mm/2.75″  stainless steel tripod legs with a wider stance for improved stability under heavy loads
  • Spring-loaded brass worm wheel and stainless steel worm gear reduce friction and provide optimum gear mesh
  • Internal cabling for worry-free remote operation. Power input and lower accessory ports remain stationary while the mount slews to avoid snags
  • Includes Celestron’s new PWI telescope control software featuring multi-point mount modelling for extremely precise pointing accuracy
Celestron CPC Deluxe 1100 HD Computerised TelescopeOut Of Stock

Celestron CPC Deluxe 1100 HD Computerised Telescope

£4,799.00
  • Celestron 11 inch f/10 EdgeHD optics provides stunning views and sharp astroimages free of visual defects
  • Sturdy dual fork arm mount with upgraded gears and motors anchors the telescope for superior tracking and pointing accuracy
  • Re-designed drive base and drive mechanics with spring loaded RA worm block with enveloping brass teeth
  • Re-designed electronics deliver constant regulated power to the motors making them capable of driving the telescope even when not perfectly balanced
  • Computer assisted All-Star polar-alignment
  • NexStar+ hand control and internal GPS guides users through the simple SkyAlign setup and features a 40,000+ object database
  • Flash upgradeable hand control software and motor control units for downloading updates over the Internet
  • Ready for serious astroimaging, CPC Deluxe HD features All-Star Polar Alignment and Permanently Programmable Periodic Error Correction when equipped with the HD Pro Wedge
Celestron CPC Deluxe 800 HD Computerised Telescope

Celestron CPC Deluxe 800 HD Computerised Telescope

£2,949.00
  • Celestron 8-inch f/10 EdgeHD optics provides stunning views and sharp astroimages free of visual defects
  • Sturdy dual fork arm mount with upgraded gears and motors anchors the telescope for superior tracking and pointing accuracy
  • Re-designed drive base and drive mechanics with spring loaded RA worm block with enveloping brass teeth
  • Re-designed electronics deliver constant regulated power to the motors making them capable of driving the telescope even when not perfectly balanced
  • Computer assisted All-Star polar-alignment
  • NexStar+ hand control and internal GPS guides users through the simple SkyAlign setup and features a 40,000+ object database
  • Flash upgradeable hand control software and motor control units for downloading updates over the Internet
  • Ready for serious astroimaging, CPC Deluxe HD features All-Star Polar Alignment and Permanently Programmable Periodic Error Correction when equipped with the HD Pro Wedge
Celestron CPC Deluxe 925 HD Computerised TelescopeOut Of Stock

Celestron CPC Deluxe 925 HD Computerised Telescope

£3,749.00
  • Celestron 9.25 inch f/10 EdgeHD optics provides stunning views and sharp astroimages free of visual defects
  • Sturdy dual fork arm mount with upgraded gears and motors anchors the telescope for superior tracking and pointing accuracy
  • Re-designed drive base and drive mechanics with spring loaded RA worm block with enveloping brass teeth
  • Re-designed electronics deliver constant regulated power to the motors making them capable of driving the telescope even when not perfectly balanced
  • Computer assisted All-Star polar-alignment
  • NexStar+ hand control and internal GPS guides users through the simple SkyAlign setup and features a 40,000+ object database
  • Flash upgradeable hand control software and motor control units for downloading updates over the Internet
  • Ready for serious astroimaging, CPC Deluxe HD features All-Star Polar Alignment and Permanently Programmable Periodic Error Correction when equipped with the HD Pro Wedge
Out Of Stock

Celestron EdgeHD 11″ Optical Tube Assembly

£3,950.00
  • Popular 11″ aperture EdgeHD Telescope
  • 2800mm focal length (f/10 focal ratio)
  • Celestron’s StarBright XLT coatings provide maximum light transmission
  • EdgeHD’s aplanatic, flat field Schmidt-Cassegrain optics result in pinpoint stars to the edge of today’s largest imaging sensors and widest eyepieces for best optical performance
  • Aluminium optical tube with tube vents with mesh filter allows hot air to be released from behind the primary mirror for improved cooling
  • Mirror support knobs hold the mirror in place and reduce image shift during imaging
  • Focal ratio of f/7 with the addition of an optional focal reducer, or ultra-fast Fastar/Hyperstar f/2 imaging with a removable secondary mirror
  • A 9×50 finderscope, wide-angle 23 mm Luminos 2″ eyepiece, 2” mirror diagonal included

Celestron EdgeHD 14″ Optical Tube Assembly

£8,099.00
  • 14″ aperture EdgeHD Telescope
  • 3910mm focal length (f/11 focal ratio)
  • Celestron’s StarBright XLT coatings provide maximum light transmission
  • EdgeHD’s aplanatic, flat field Schmidt-Cassegrain optics result in pinpoint stars to the edge of today’s largest imaging sensors and widest eyepieces for best optical performance
  • Aluminium optical tube with tube vents with mesh filter allows hot air to be released from behind the primary mirror for improved cooling
  • Mirror support knobs hold the mirror in place and reduce image shift during imaging
  • Focal ratio of f/7 with the addition of an optional focal reducer, or ultra-fast Fastar/Hyperstar f/2 imaging with a removable secondary mirror
  • A 9×50 finderscope, wide-angle 23 mm Luminos 2″ eyepiece, 2” mirror diagonal included
Out Of Stock

Celestron EdgeHD 8″ Optical Tube Assembly

£1,549.00
  • Popular size 8″ aperture EdgeHD Telescope
  • Available with CG-5/Vixen or CGE/Losmandy dovetail bar
  • EdgeHD’s aplanatic, flat field Schmidt-Cassegrain optics result in pinpoint stars to the edge of today’s largest imaging sensors and widest eyepieces for best optical performance
  • Aluminium optical tube with tube vents with mesh filter allows hot air to be released from behind the primary mirror for improved cooling
  • Mirror support knobs hold the mirror in place and reduce image shift during imaging
  • Versatile optical design accommodates 3 focal ratios: native f/10, f/7 with the addition of an optional focal reducer, or ultra-fast f/2 imaging with a removable secondary mirror and third-party accessories
  • Celestron’s StarBright XLT coatings provide maximum light transmission
Out Of Stock

Celestron EdgeHD 9.25″ Optical Tube Assembly

£2,750.00
  • Popular size 9.25″ aperture EdgeHD Telescope
  • EdgeHD’s aplanatic, flat field Schmidt-Cassegrain optics result in pinpoint stars to the edge of today’s largest imaging sensors and widest eyepieces for best optical performance
  • Aluminium optical tube with tube vents with mesh filter allows hot air to be released from behind the primary mirror for improved cooling
  • Mirror support knobs hold the mirror in place and reduce image shift during imaging
  • Versatile optical design accommodates 3 focal ratios: native f/10, f/7 with the addition of an optional focal reducer, or ultra-fast f/2 imaging with a removable secondary mirror and third-party accessories
  • Celestron’s StarBright XLT coatings provide maximum light transmission
  • A 9×50 finderscope, wide-angle 23 mm Luminos 2″ eyepiece, 2” mirror diagonal included
Out Of Stock

Celestron Limited Edition NexStar Evolution 8 HD Telescope with StarSense – 60th Anniversary Edition

£3,095.00
  • 60th anniversary special edition run of only 600 units
  • Each telescope comes with a unique serial number and certificate of authenticity signed by Celestron pioneer Alan Hale and CEO Corey Lee
  • EdgeHD optics provide superb visual and astroimaging performance free of coma and field curvature
  • Carbon fibre telescope tube to minimise thermal expansion with ambient temperature changes
  • Retro details and all-new look with vintage-style badging and logos and a set of 3 interchangeable emblems
  • Rechargeable lithium-iron phosphate battery with enough power for 10 hours of continuous observing
  • Built-in WiFi – No hand control required! Use your smartphone or tablet to control the telescope via WiFi
  • StarSense AutoAlign automatically aligns your telescope in about 3 minutes
  • Fastar compatible so you can image deep sky objects at f/2, often eliminating the need to autoguide or track on a wedge
  • NexStar Evolution mount packed with convenient features including a USB charge port, adjustable lighting and precision machined worm gears for both axes
  • Includes 3 quality eyepieces – 32mm (2”), 15mm, and 9mm (both 1.25”), StarPointer Pro™ finderscope, StarSense AutoAlign, 2″ star diagonal with 1.25″ adaptor and more.
Out Of Stock

Celestron NexStar Evolution 8 HD with StarSense

£2,575.00
  • 8” EdgeHD Optics: Provides superb visual and astro-imaging performance, free of coma and field curvature.
  • Rechargeable lithium-iron battery with enough power for 10 hours of continuous observing
  • Built-in WiFi: No Hand controller required! Just use your smartphone or tablet which connects to the telescope via WiFi.
  • StarSense Auto Align: Automatically aligns your telescope and works with the SkyPortal app for complete wireless control.
  • Fastar/HyperStar compatible: Image deep sky objects in seconds at f/2, often eliminating the need to autoguide or track on a wedge.
  • NexStar Evolution Mount: Packed with convenient features, including manual release clutches and precision machined worm gears for both axes, tray lighting, USB charge port, tray lighting for your accessories, and more.
  • Fully motorized computer go-to: After automatically aligning with StarSense, select and go to objects with a tap on your smartphone.