Celestron - Accessories

NexImage is a complete CCD solar system imager capable of producing high quality planetary images with greater light sensitivity and color fidelity than comparable CMOS imagers. Combined with the NexImage software package, NexImage can bring out tremendous detail and reveal a final image that will rival those taken with astronomical CCD cameras costing thousands of dollars more. For more about this product see our NexImage section.

Counterweights

Item #94186, Counterweight, Extra 11# (for CG-5 Mount)
Item #91525-2, Counterweight, Extra 25# (for CGE Mount)
Item #94188, Counterweight, Extra 11# (for 8 CGE Mount)

Using accessories such as cameras, Lens Shades, Tele-Extenders and the 2" Diagonal will affect the balance of your Celestron Schmidt-Cassegrain telescope. Counterweights restore proper balance, increasing ease in handling and improved tracking accuracy.

You don’t need perfect balance to operate your telescope. In fact, it’s not always possible to achieve perfect balance with fixed-position weights. All you need to do is reduce, or eliminate, swing when R.A. and DEC locks are released. Celestron counterweights help you achieve the desired balance and stability with ease.

Counterweight Bar Assembly

Item #94191, Counterweight Bar Assembly - 8" Schmidt-Cassegrain
Item #94192, Counterweight Bar Assembly - 11" Schmidt-Cassegrain
Item #94193, Counterweight, Extra 2.5# (for #94191 & #94192)

The Counterweight Bar Assembly is a metal rail that runs the length of the telescope tube. It attaches to both the front and rear cells of 8"and 11" SCT. Once the Bar Assembly is in place, counterweights can be attached to it and moved along its length, as well as perpendicular to it, for better dynamic balancing. Each Counterweight Bar Assembly comes with mounting hardware and one 2.5 lb. weight.

Fastar Lens Assembly

Fastar

Item #94180, Fastar Lens Assembly - 8"
Item #94181, Fastar Lens Assembly - 14"

Celestron’s long history of being a leader in innovation began in the early 1960’s when it was the first to mass produce the Schmidt Cassegrain Telescope (SCT), known to all as the C8. Today, the term "C8" is synonymous with the SCT. Celestron was also the first to introduce a Schmidt Camera and a completely computer automated fork mounted telescope to the amateur astronomer. In keeping with this tradition of innovation, Celestron has designed multi-focus Fastar compatible SCT telescopes. In addition to using your telescope in the traditional photo/visual configurations, these telescopes are optimized for f/2 (f/1.95 with the C8 and f/2.1 with the 14") prime focus CCD imaging.

	Fig. 1
	Fig. 2

Figure 1 on the top is the conventional SCT optical system. The Fastar configured optical system on the bottom, figure 2, uses a corrector lens assembly with a CCD camera placed at prime focus where the Cassegrain secondary mirror would be.

The Fastar lens assembly comes with the optical lens assembly, and protective holder for the secondary mirror while removed from the telescope. A rear cell counterweight to ensure proper balance when imaging at f/1.95 is also included with the 8" systems.

With the Fastar's f/2 focus, your telescope can provide a field of view larger than CCD systems twice its chip size and costing thousands of dollars more. Objects like M33 and the Veil Nebula, which were previously too large for the narrow fields of view of most commercial CCD's, will easily be seen with the Fastar system. The Fastar compatible C8 used at f/1.95 delivers a field of view 5 times wider than imaging at f/10 and requires exposure times that are 25 times shorter. No more spending valuable observing time trying to locate and frame deep-sky objects in a small field of view. Unguided track and accumulated images of 30 seconds or more capture deep sky objects in their full glory. It's like having a professional observatory in your own backyard!


Tricolor Trifid Nebula (M20) with C8 @ f/1.95. R=2 min, G=2 min, B=2 min	Pinwheel Galaxy (M33) captured with a C14 @ f/2.1 and the Pixcel 237 and Color Filter Wheel accessory. R=4 @ 1 min, G=4 @ 1 min, B=8 @ 1 min

M31 Andromeda Galaxy
4 image mosaic exposed for 2 minutes each with a C8 @ f/1.95 and PixCel237

Radial Guider

Radial Guider Item# 94176

Item #94176, Radial Guider

Specifically for use in prime focus, deep-sky imaging or astrophotography with Schmidt-Cassegrain telescopes, the Radial Guider is compact and sleek in design. This accessory makes it possible to simultaneously photograph and guide through the optical tube assembly of your telescope. The Radial Guider also eliminates the problem of differential flexure, because you’re both guiding and photographing through the telescope.

The Radial Guider is compatible with Celestron’s C5, C8, C9¼, C11 and C14 telescopes and comes with a unique prism angle adjustment screw. It must be used with a guiding eyepiece, camera T-Ring and drive corrector (dual axis preferred). Primarily for use with catadioptric telescopes, but also works on refractor telescopes having adequate back focus.

This guider is a tremendous improvement over conventional off-axis guiders. Not only is the angle of the prism tunable, but it also maintains a fixed rigid camera orientation while still offering users the freedom to move the guiding eyepiece radially about 135°.

Reducer / Corrector f/6.3

Reducer/Corrector Item# 94175

Item #94175, Reducer/Corrector f/6.3

This combination focal reducer and field corrector lens accessory works with all Celestron 5", 8", 9 1/4", 11" and 14" Schmidt-Cassegrain telescopes. This clever accessory makes it possible to have a dual focal ratio instrument, without sacrificing image quality. The Reducer/Corrector is f/6.3 for C5, C8, C9¼ and C11 telescopes and f/7 for the C14 telescope.

If offers wide fields of view with any Schmidt-Cassegrain telescope. Used for astrophotography, it reduces exposure time by a factor of 3.

Celestron doesn’t offer a f/6.3 Schmidt-Cassegrain telescope, because the design is impractical, with a large central obstruction, and resulting loss in contrast. This, added to the inability to utilize longer focal ratios for certain objects, led Celestron to design the four-element, fully multicoated f/6.3 Reducer/Corrector. Results are amazing both visually and photographically.

T-Adapters

Item #94177, T - 1/-1/4" Adapter (for CCD's)
Item #93625, T-Adapter, Universal - 1-1/4"
Item #93633-A, T-Adapter, (C5, 8, 9 1/4, 11, 14)
Item #93635-A, T-Adapter, NexStar 4GT
Item #93628, T-Adapter, 52200 Spotter
Item #93634-A, T-Adapter, Refractors
Item #93640, T-Adapter/Barlow Lens Universal 1-1/4"

T-Adapter Diagram

A T-Adapter allows you to attach your 35mm SLR camera to the prime focus of your telescope or spotting scope. This arrangement is used for terrestrial photography and short exposure lunar and planetary photography. It can also be used for long exposure deep-sky photography when using a separate guidescope.

Both a T-Adapter and T-Ring are required to mount a 35mm SLR camera to your instrument. T-Adapters are available for the following Celestron instruments — some instruments have built-in T-Adapters (see your instruction manual):

T-C 16mm Adapter

T-C 16mm Adapter Item# 93636

Item #93636

This valuable adapter converts video cameras, (or 16mm film cameras) with removable lenses from the standard "C-mount" thread, to the larger T-thread used in still cameras. Thus, any of these cameras can be converted for use with a telescope.

To adapt a C-mount camera for use with a Celestron instrument, first thread the T-C Adapter onto the camera, next thread a T-Adapter onto the T-C Adapter, and last, thread this assembly onto the rear cell of your Celestron instrument.

Please note that some film and video cameras use standard still camera lenses, and therefore use a normal T-Adapter and T-Ring. Check your camera’s instruction manual for more detailed information.

T-Rings for 35mm SLR Cameras

Item #93413, Canon
Item #93419, Canon EOS
Item #93400, Minolta
Item #93418, Minolta Maxxum
Item #93402, Nikon
Item #93414, Olympus
Item #93401, Pentax – Universal M42 Thread Mount
Item #93403, Pentax K – Universal Bayonet Mount

A T-Ring couples your 35mm camera body to a T-Adapter, Radial Guider or Tele-Extender. This accessory is required if you want to do any type of photography through a telescope or spotting scope. Each camera manufacturer has a different mount, which requires a specific T-Ring, so Celestron offers a full line of T-Rings.

To use a T-Ring, remove the diagonal and/or eyepiece from your telescope (some models require use of an eyepiece — see your instruction manual). Then you need only remove your normal camera lens, attach the proper T-Ring for your camera, and mount the combination to the rear cell of your telescope or spotting scope with a Celestron T-Adapter.

If you own an older SLR camera with a thread mount, it will probably accept the Pentax Universal Thread Mount T-Ring. If you have a new camera with a bayonet mount not listed above (Ricoh, Cosina, etc.), it most likely accepts the Pentax K-Universal Bayonet Mount T-Ring. Check your camera’s instruction manual for more detailed information.

Tele-Extender - Deluxe

Tele-Extender Item# 93643

Item #93643

The Deluxe Tele-Extender for Schmidt-Cassegrain telescopes is a hollow tube that allows you to attach a camera to your telescope, with an eyepiece installed. By using the Deluxe Tele-Extender in combination with an eyepiece, you can increase your instrument’s effective focal length to well over 10,000mm! And this corresponds with a matching increase in image size. This technique is known as eyepiece projection photography. The following formula can be used to determine approximate effective focal length: Tele-Extender Diagram

EFL = Telescope focal length/Eyepiece focal length x DF (the distance from the center of the eyepiece to the film).

The Deluxe Tele-Extender is used for high-power lunar, solar and planetary photography as well as for extreme terrestrial photography. It fits over the telescope’s eyepiece (even large eyepieces such as those in Celestron’s Ultima line), and connects to the visual back of the telescope. Optional counterweights will be necessary to properly balance the telescope when using the Tele-Extender.

To use the Deluxe Tele-Extender, remove the diagonal from your telescope and insert an eyepiece directly into the visual back. Place the Tele-Extender over both the eyepiece and the visual back, then attach your 35mm SLR camera to the back of the Tele-Extender, using a T-Ring. The Tele-Extender’s built-in safety device will help prevent your eyepiece from becoming accidentally dislodged.

There are a few things to keep in mind when using this accessory. First, the image you’ll see through your camera’s viewfinder will be upside-down. Secondly, due to the extremely high magnifying effect afforded by this accessory, extra care to prevent camera and telescope vibration, accurate polar alignment and use under good seeing conditions will all assist you in capturing high quality images.