Celestron - Accessories

Eyepiece filters are an invaluable aid in lunar and planetary observing. They reduce glare and light scattering, increase contrast through selective filtration, increase definition and resolution, reduce irradiation and lessen eye fatigue. Celestron's filters are made of high quality, solid plane parallel glass with excellent homogeneity. They're anti-reflection coated to prevent glaring and ghosting. All eyepiece filters are threaded to fit Celestron's, and most other manufacturer's, 1¼" eyepieces, and offer a full 26mm clear aperture.

Celestron color filters are mounted in black anodized aluminum cells with the Kodak Wratten Series Number individually engraved, and come available in 4 assorted kits packed in plastic cases. The cells of each filter are double-threaded, so they can be stacked (piggybacked) in various combinations. This allows you to create different color combinations and transmission characteristics, or to have the same color characteristic, but with a lower transmission. When stacking color filters, the effective transmission of the combination you create is equal to the product of the spectral transmission of each of the filters used.

The effectiveness of the filters depends on several factors, including: the aperture and focal length of the telescope, the magnification being used, and seeing conditions.

Light Pollution Reduction (LPR) Filters are designed to selectively reduce the transmission of certain wavelengths of light, specifically those produced by artificial light. This includes mercury vapor, and both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. sky glow). The new ultra high contrast (UHC) LPR filter has improved contrast over the typical broadband filters. Sky background is darker, and contrast of emission nebulae are noticeably improved. The advanced technology coatings enable the filter to achieve an outstanding transmission of over 97% across the entire bandpass, with total blockage of prominent light pollution lines. The perfect filter for viewing nebula from light polluted skies, or for boosting the contrast of nebula from dark sky sites.

In addition to it's optimum spectral and optical characteristics, the UHC/LPR filter offers important features that set it apart and result in the highest quality celestial views:

The multi-layer dielectric coatings are plasma assisted and Ionbeam hardened using the latest technology for durability and resistance to scratching.
Improved transmission translates to maximum image brightness and contrast. Users of smaller, 4"-11" telescopes will especially appreciate the high efficiency, and larger scope users will love the rich star fields and detailed subtle nebular shadings that are left intact.
The high transmission, sharp cutoffs, and more moderate 60nm passband of the UHC/LPR filter retains a more natural view, yet significantly boosts overall contrast. Imagers will appreciate the broader bandpass and inclusion of an extremely efficient H-Alpha passband (656nm)

Narrowband OIII Filter – 1 ¼" (#93623)
Narrowband OIII Filter – 2" (#93624)

The OIII narrowband filter isolates just the two doubly-ionized oxygen lines (496 and 501nm lines) emitted by planetary and emission nebulae, while blocking the rest of the overall spectrum of light. The result is extreme contrast between the black sky background and the faint photons of OIII light needed for detailed views of the Veil, Ring, Dumbbell, Crescent and Orion nebulae, among other objects. Each filter has an ultra hard, vacuum-deposited coating carefully designed to block all of the visual spectrum ranging from 400 to 700 nm This eliminates the un-natural colored halos surrounding bright stars common with O III filters of less sophisticated coating technology.

The ultimate UV and Infrared blocker, featuring hard Ionbeam coatings, and fine optically polished glass! The ideal filter for NexImage and CCD imaging. This filter has an extremely sharp cutoff at 690nm yet leaves all the visible red, including the important 656nm H-alpha emission line, preventing IR wavelengths from blurring fine detail in your digital images.

Item #94119-10, 1-1/4" (21, 80A, #15, Polarizing)
Item #94119-20, 1-1/4" (12, 25, 56, ND-25)
Item #94119-30, 1-1/4" (23A, 38A, 58, ND-50)
Item #94119-40, 1-1/4" (8, ND-13, 47, 82A)

Item #94121

1-1/4" by Baader

This is our newest high quality filter that eliminates most color aberration inherent in achromatic refractor telescopes. The filter also reduces your view of the blue hue around lunar and planetary subjects. Features multi-layer coatings for 95% transmission.

Moon Filter

Moon Filter Item# 94119-A

Item #94119-A

Moon Filter - 1-1/4"

Celestron’s Moon Filter is an economical eyepiece filter for reducing the brightness of the moon and improving contrast, so greater detail can be observed on the lunar surface. The clear aperture is 21mm and the transmission is about 18%.

Polarizing Filter Set 1-1/4"

Polarizing Filter Set Item# 93608

Item #93608

Ambient daylight is normally comprised of multiple wavelengths of light, vibrating in multiple planes. The Eyepiece Polarizing Filter Set transmits only light moving along a specific plane, thereby increasing the contrast between surfaces with different planar transmissions. Generally, the polarization effect makes blue skies a deeper blue, eliminates surface reflections and helps reduce atmospheric haze. The Polarizing Filter Set is intended for visual use. It’s particularly useful for reducing glare while observing the moon, double stars, the planets and terrestrial subjects – all without affecting the color of the object being observed. The Filter Set is comprised of two filters that thread into either the eyepiece or the filter adapter, which comes with the set. When one filter is used alone, you get 30% light transmission. When both filters are used together, you can vary the degree of transmission. By causing the amount of transmitted light to vary, the filters become, in effect, a continuously variable neutral density filter. At maximum density, the Polarizing Filter Set transmits only 5% of entering light.

Skylight Filter

Skylight Filter Item# 93621

Item #93621

For Schmidt-Cassegrains

If you were to use only one filter, Celestron’s Skylight Filter/Dust Seal would be your most versatile choice. This general purpose, Wratten #1A filter improves color saturation and balance, increases visual and photographic contrast, helps to decrease glare in lunar and planetary observing, and penetrates atmospheric haze. It’s also an inexpensive way to protect your investment in quality optics. This filter threads onto the rear cell of your Celestron C5, C8, C9 1/4, C11 or C14 telescope to serve as an effective dust seal. By leaving the Skylight Filter/Dust Seal on when removing or attaching other visual accessories, you prevent dust and other atmospheric contaminants from entering the rear of your telescope. Needless to say, it’s much easier to clean a dusty filter than a dusty primary mirror, secondary mirror and corrector plate.

The Skylight Filter/Dust Seal must be threaded onto the rear cell of the instrument before any other accessory is installed. The female end attaches to the rear cell of the C5, C8 and C9 1/4 telescopes and the reducer plate of the C11 and C14 telescopes. All additional accessories mount onto the exterior/male threads.

Solar Filters

Solar Filter

Item #94131, FirstScope 60AZ, 60EQ
Item #94135, FirstScope70EQ, 80AZ, 80EQ, NexStar 60, NexStar 80
Item #94133, FirstScope 76EQ
Item #94138, C4 R, FirstScope 102AZ
Item #94136, C6 R
Item #94139, C5 S, NexStar 5i, NexStar 130GT
Item #94162, For C8 S, NexStar 8i, NexStar 8 GPS

Celestron Solar Filters are made with Baader Astro Solar™ Safety Film. Far superior than any existing glass, Mylar or polymer filters, they lead to brighter, sharper, and higher contrast images.

Enter the new millennium with the finest solar filters available. Astro Solar™ Safety Film is clear and homogenous and attains the optical performance of high quality plane-parallel glass filters—it is diffraction limited! Double-sided metal coatings have uniform density and good color balance across the entire field ensuring razor sharp images from edge to edge.

The Sun appears in its “real ”color —neutral white, not blue or orange ,and the sky adjacent to the solar limb is jet black.

You can see detail in sunspots, bright faculae near the limb and the mottled areas known as granules with these filters. The Sun offers constant changes and will keep your observing interesting and fun. Even small aperture telescopes can enjoy features of the Sun.

The Astro Solar™ film is completely safe and durable (won‘t break like glass if dropped). Its rating is ND-5 which means that the film transmits 1/100,000 of visible light (.001%) while reflecting (blocking) 99.999%of unwanted light. The film absorbs all ultraviolet rays while coating reflects infrared light rendering both absolutely harmless. For added assurance, Baader Astro Solar™ film has been declared safe for direct solar viewing by the German National Bureau of Standards for eye safety.

Celestron has previously manufactured high quality, plane-parallel glass solar filters (unlike today ’s glass filters which generally are poor in quality with reduced contrast). Celestron has offered Mylar solar filters (they were the best previously available) but they suffer from a lot of scattered light and false color. Polymer filters suffer from not only scattered light but also have reduced sharpness and contrast due to their increased thickness. So, “we‘ve been there and done that” and after all these years are now offering the finest solar filters available for observing. Each is mounted in a durable ABS or rubber cell that won‘t break.