Basic forms of predominantly used types of astronomical eyepiece, positioned to focus at the focal plane FP of the objective, with the approximate range of the exit pupil Ex. The simplest - Kellner - features 45°-50° apparent field and satisfactory correction for spherical aberration at ~ƒ/5 and bellow. Plössl has better overall correction, and goes as the best balanced conventional eyepiece type. Orthoscopic (Abbe) has somewhat smaller field, and not quite as good correction. Conventional wide-fields, König and Erfle, have better spherical correction but more intrusive astigmatism, due to their larger, 60°-70° fields. Most of today's standard wide-fields are variations of these two basic concepts. Nagler (Type 1), whose negative front lens enables better correction of astigmatism, offers well corrected fields exceeding 80°. Wide exit pupil range indicates intrusive spherical aberration of the exit pupil ("kidney bean effect"), better corrected with later types. Darker color tone indicates elements of higher refractive indici. (data from Telescope Optics, Rutten/Venrooij)

New 80° Eyepiece Series

1.25" 1.25"  

1.25" Wied Field

2" 15mm Wide angled



Plossl Eyepice

Product Description
With a wide 50-deg apparent field, our Sirius Plossl line of eyepieces provide clear, sharp images of impressively high contrast. They're suitable all telescope types: reflector, refractor, and catadioptric. Each 4-element Sirius Plossl is fully coated with magnesium fluoride on every air-to-glass surface. Lens edges are blackened to reduce scattering of stray light and maximize contrast. Lenses are mounted in black anodized aluminum housings with 1.25" chrome-plated brass barrels. Each is fitted with rubber eyeguards and internally threaded to accept standard filters.

·  1.25"- Flat eyepiece-
60 degree --8mm, 12mm 
60 degree --16mm
65 degree --19mm
53 degree --27mm
·  Edge-On Eyepieces offer premium performance at an amazing price!

·  Flat-field design means sharp focus from edge to center of the viewing field.
·  Features multicoated optics, all-black anodizing, twist-up eye guards, and parfocal design.
·  Large eye lens and long eye relief mean comfortable viewing - even for long observing sessions.
·  Threaded to accept all BST 1.25" filters.

ZOOM Eyepiece




For more details about Eyepiece 9mm & 15mm, click here




1.25 inches 62 degree 10 mm eyepiece wide-angle high-powered Astronomy telescope ocular Accessories for CELESTRON ....For more details Click Here


Galileo A2-32 32mm 2 Inch Eyepiece

Galileo 2 inch Astroscopic eyepieces are the ultimate eyepiece for bright clear images. Massive 2 inch format allows for extreme light transmission creating incredibly bright images. That fact, together with the 55° apparent field of view, the Galileo 32mm 2 inch eyepiece will show you everything you've been missing by using smaller format eyepieces. The Galileo A2-32 is a 3 element, fully color corrected, fully multi-coated modified Rank Kasspheric eyepiece.
The Galileo A2-32 32mm 2 Inch Eyepiece Features and Benefits:

  • Format: 2″
  • Focal Length: 32mm
  • Apparent F.O.V.: 55°
  • Elements: 3
  • Design: Modified Rank Kasspheric
  • Fully Color Corrected
  • Fully Multi-Coated
Galileo A2-32 32mm 2 Inch Eyepiece

Focal reducer

A focal reducer may be thought of as just the opposite of a barlow lens. Barlow lenses increase the power and focal length of a telescope. These focal reducers reduce the power and effective focal length. An f/10 SCT becomes an f/5 SCT telescope. An f/6 reflector becomes an f/3. It does not change the apparent field of view of an eyepiece, but increases the true field. It doubles the true field of view and decreases the required photographic exposure for an object by a factor of 4.
NOTE: There are some similar products available. In our testing these will not achieve a true 0.5X focal reduction without using an extension tube. This model, which was designed in our shop, will achieve the 0.5X directly. It will get even more reduction with an extension tube.
To use a focal reducer, you screw the lens onto the filter thread of your eyepiece. You may also use this with our C-mount adapter to adapt you C-mount video camera to your telescope. This focal reducer effectively divides the focal length (and f/ratio) of the telescope by 2. This will allow you see a wider true field of view with any eyepiece. You may use any of your standard 1-1/4" (31.75 mm) eyepieces with this as long as they have the standard filter thread. If you want to look at it the other way, it doubles the focal length of the eyepiece.
Please Note: Using the focal reducer on your eyepiece requires you to focus inward on most telescopes about 20 mm. This is not usually a problem but could cause you to be unable to focus the telescope in the few telescopes that do not allow this inward travel. This will be NO PROBLEM on SCTs and similar telescopes. The exact amount of inward focus depends on the eyepiece. The 20 mm is based on our Plossl eyepieces using our reflector telescope that we used for most tests.

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