User`s guide

14 I The Celestron EdgeHD
FIGURE 14. It is easy to position your digital SLR camera, an astronomical CCD camera, a high-performance video camera, or an
inexpensive webcam at the focus plane of your EdgeHD telescope. For the sharpest wide-field imaging, your goal is to place the
sensor 5.25 inches behind the rear flange of the EdgeHD 800, or 5.75 inches behind the rear flange of the EdgeHD 925, 1100,
and1400.
5.75 inches
146.05±0.5 mm
5.25 inches
133.35±0.5 mm
EdgeHD
800
EdgeHD
925, 1100,
and 1400
Small T-Adapter
Camera Adapter
Digital SLR
Reducing Ring
Small T-Adapter
T-to-1.25” Adapter
Webcam
Large T-Adapter
T-Ring Adapter
Digital SLR
Large T-Adapter
T-to-C Adapter
Astro Video Camera
Large T-Adapter
T-system Spacer
CCD Camera
For those who wish to make images with a faster focal ratio
than EdgeHD 1100’s ƒ/10 or the EdgeHD 1400’s ƒ/11, we
designed a five-element 0.7× reducer lens for each of these
EdgeHD telescopes. (For more information, see Appendix B.)
The Reducer Lens 0.7× for the EdgeHD 1100 is item #94241;
for the 14-inch, item #94240. (The newly-released EdgeHD
800 Focal Reducer is item #94242.)
The reducer lens attaches directly to the 3.290×16 tpi threaded
baffle tube lock nut on the back of the telescope. Since the back
focus distance for the 1100 and 1400 reducer lens is 5.75 inches
(146.05mm), you can use the same T-Adapter and camera
T-Ring you would use for imaging at the ƒ/10 or ƒ/11 focus. The
linear field of view is still 42mm diameter, but the angular field is
43% larger, and exposure times drop by a factor of two.
For super-fast, super-wide imaging, the EdgeHD telescope
series supports Starizona’s Hyperstar lens. Mounted on the
corrector plate in place of the secondary mirror, the Hyperstar
provides an ƒ/1.9 focal ratio on the EdgeHD 1400, and ƒ/2.0 or
ƒ/2.1 on the 800, 925, and 1100. Covering a 27mm diameter
field of view, the Hyperstar is a perfect match for APS-C format
digital SLR cameras. Because of the short focal length and
fast focal ratio, sub-exposures are just a minutes. With a solid,
polar-aligned equatorial mount, guiding seldom necessary.
Of course, the focal length of any EdgeHD telescope can be
extended using a Barlow lens such as the Celestron 2x X-Cel
LX (item #93529) or 3x X-Cel LX (item #93428). Using a
Barlow, imagers can reach the desirable f/22 to f/32 range for
ultra-high-resolution lunar and planetary imaging.
In summary, the Celestron EdgeHD telescopes provide a flexible
platform for imaging. You can work at the normal ƒ/10 or ƒ/11
Cassegrain focus for seeing-limited deep-sky images or add
the reducer lens for wider fields and shorter exposure times.
With a Hyperstar, you can grab wide-field, deep-sky images
in mere minutes. And finally, you can extend the focus to capture
fine lunar and planetary images with a quality Barlow lens.
When you buy an EdgeHD telescope, you’re getting an imaging
platform that covers all the bases, from fast, wide-field imaging to
high-resolution imaging of the moon and planets.
Celestron's EdgeHD: The Versatile Imaging Platform