The Celestron EdgeHD telescope: Corrected image - sharp right up to the edges!
EdgeHD is the name for Celestron’s “aplanatic Schmidt Cassegrain telescope”. After over 50 years of success, Celestron has revolutionised the classic Schmidt Cassegrain telescope.
EdgeHD telescopes ( "Edge High Definition") are true astrographs. This optical system delivers distortion-free, sharp images right to the edge of the visual field. This means that not only the coma outwith the optical axis is corrected, as is the case in currently available “coma-free” lens designs, but also field curvature.
Lots of optical systems are advertised as “astrographs”. As desired, they display stars with pin-sharp clarity, but along a curved image plane. Photographing this using a camera results in a noticeable image field curvature which rises towards the edge of the image field, resulting in increasing star size and aberations with larger sensors. The stars at the edge expand into small rings (“doughnuts”). As well as the coma, the Celestron Edge HD telescopes correct field curvature right up to the edge of the image. This also significantly improves resolution and magnitude limits in comparison to rival optical systems.
The XLT multi-coating helps to give the EdgeHD scopes a significant performance boost compared to similar systems on the market.
The Edge HD telescopes’ mechanisms and lens tube have been fully overhauled:
- mirror clamps hold the primary mirror securely in any desired position without putting pressure on the optical elements. The image is stable, even during long exposure times.
- Air vents behind the primary mirror provide fast air exchange so that the lens cools amazingly quickly. Thanks to an air filter system, dust is prevented from entering the lens tube.
The Celestron CPC mount: The Schmidt Cassegrain scopes in the CPC series are securely mounted in a sturdy, cast aluminium fork mount. This means the telescope tube cannot be changed. However, this disadvantage is counteracted by their compact size, lack of need for heavy counterweights and excellent transportability. Yet, its greatest advantage is its unbelievably fast set-up and alignment. You are ready for observing within a few minutes - whilst others are still tightening screws and carrying out alignment. Simply set the tripod up at the desired height for either sitting or standing observation, level it using the built-in spirit level, fit the fork mount (sits in the middle), secure using the three spring-loaded screws - and switch on.
SkyAlign: The 16-channel GPS receiver sends satellite information about local time, date and coordinates to the electronic system. For initialisation (also known as alignment), the telescope needs to be pointed towards three bright objects in the sky in turn. These could be the Moon, bright planets or bright stars. You do not need to know what objects they are. This is a huge advantage at dawn!
After the third object, the telescope calculates a precise model of what it is seeing relative to the night sky. To achieve this, the electronic system carries out up to 120,000 comparative operations within a few seconds comparing the angles between the three objects against the planetarium catalog stored on the on-board computer. This extremely simple initialisation process for the GoTo controls has been named SkyAlign by Celestron.
Following alignment, over 40,000 database objects are instantly locatable. Up to 100 objects can be saved within the controls, including current comets for example.
The controls not only navigate to selected objects, but also provide recommendations depending on the night and current time. Information on numerous objects is also displayed on the ticker on the remote control’s display.
Furthermore, when the CPC telescope is placed on the optional equatorial wedge, another Celestron technology becomes available in addition to SkyAlign. Thanks to the All-Star Polar Alignment, you do not need a polarscope or view of the Pole Star to align the telescope.
The CPC mount properties at a glance:
- Drive and mechanism for quiet operation, with large gears and quick-lock coupling
- Autoguider and PC connections
- Secure self-centring on tripod.
- SkyAlign technology: Simply select three celestial objects and the telescope will tell you what they are.
- Comfortable mount for remote control: Information visible in display so hands remain free for working with optical accessories.
- Database featuring over 40000 celestial objects.
- The remote control software and motor control unit can be updated via the internet using Flash technology.
- Easy-to-find large coupling knobs on both axes for manual operation.
- Quick-release, spring-loaded solid metal finderscope mount with easy-to-operate x-y alignment.
- Tracking base with extra-large 25cm shelf provides quiet, stable tracking for telescopes of all sizes.
- Ergonomic design: The telescope can be comfortably transported from place to place.
- Permanent periodic error correction (PEC) with optional equatorial wedge for perfect astrophotos.
An important feature of the CPC telescope is its high-load-bearing tripod with stainless steel legs and cast aluminium accessory shelf/tripod spreader for high stability, with spring-loaded mounting screws and central locking device for quick set-up, height-adjustable for standing or sitting observations.
It not only matters which telescope you buy but also where you buy it. Our additional services:
- We are a leading telescope dealer and know the devices we sell. Our customer service team will gladly help you after your purchase if you have problems with assembly or operation.
- We provide a copy of the 80-page Telescope ABC beginners handbook with every telescope.
