| Description: | 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, and both high and low pressure sodium vapor lights. In addition, they block unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. sky glow). As a result, Celestron LPR Filters darken the background sky, making deep-sky observation and photography of nebulae, star clusters and galaxies possible from urban areas. LPR Filters are not used for lunar, planetary or terrestrial photography.
While blocking unwanted light, Celestron LPR Filters permit the transmission of more desirable wave-lengths. The wavelengths included are hydrogen alpha, hydrogen beta, doubly ionized oxygen and singly ionized nitrogen. This will improve your viewing of emission nebulae, both from urban and rural settings. Some examples of objects that will show improved contrast are: the Orion Nebula, the Rosette Nebula, the North American Nebula, the Veil Nebula and the Helix Nebula.
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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 filters are mounted in black anodized aluminum cells with the Kodak Wratten Series Number individually engraved, and come with a plastic case for safe storage. 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.
Following, you’ll find descriptions of all of Celestron’s eyepiece filters and what you can expect from them in different viewing situations. Some of these filters are available individually, and others are available in convenient four filter sets Celestron has put together to affordably expand your range of observing options.
You’ll find the information on these filters arranged in the following color categories: Yellow, Orange, Red, Blue, Green and Violet. In each category, the information that applies to all of the filters within that color group is listed, then specific information for each filter is broken out into a separate category, where applicable. This way, you’ll know what to expect from each of Celestron’s color filters. At the same time, you’ll become familiar with the astounding variety of enhancements available through these simple accessories.
YELLOW
#12 Deep Yellow 74% T [#94118-03 & Series 2]
#15 Deep Yellow 67% T [Series 4]
Moon – Enhance lunar features. Jupiter – Penetrate and darken atmospheric currents containing low-hue blue tones. Enhance orange and red features of the belts and zones. Useful for studies of the polar regions. Mars – Reduce light from the blue and green areas which darken the maria, oases and canal markings, while lightening the orange-hued desert regions. Also sharpen the boundaries of yellow dust clouds. Neptune – Improve detail in larger telescopes (11" and larger apertures). Saturn – Penetrate and darken atmospheric currents containing low-hue blue tones. Enhance orange and red features of the belts and zones. Uranus – Improve detail in larger telescopes (11" and larger apertures). Venus – Reveal low-contrast surface features. Comets – Enhance definition in comet tails.
#8 Yellow 83% T [Series 4]
All observing information for this filter is the same as that given for the #12 and #15 Deep Yellow filters, with the exception of the following:
Mars – Improves the Martian maria by reducing scattered light from blue areas, while allowing passage of more green light for studying yellow dust clouds. Comets – Brings out highlights in yellowish dust tails and enhances appearance of comet heads.
ORANGE
#21 Orange 46% T [#94118-05 & Series 1]
Moon – Greatly enhances lunar features. Jupiter – Improves appearance and detail revealed in structure of Jovian belts. Enhances viewing of festoons and polar regions. Mars – Reduces light from the blue and green areas which darken the maria, oases and canal markings, while lightening the orange-hued desert regions. Also sharpens the boundaries of yellow dust clouds. Mercury –Reduces the brightness of blue sky during daylight observing, to reveal surface features. Saturn – Improves structure of the Saturnian bands and highlights blue polar regions. Venus – Use during daylight observing to reduce brightness of blue sky. Comets – Enhances definition of comet dust tails and heads in larger telescopes (11" and greater aperture). Solar – When using a Celestron Mylar Solar Filter, adding this orange filter will give true color rendition.
RED
#25 Red 14% T [#94118-07 & Series 2]
Moon – Improves lunar features. Jupiter – Useful for studying bluer clouds. Mars – Ideal for observation of the polar ice caps and features on the Martian surface. Sharpens the boundaries of yellow dust clouds. Mercury – Improves observation at twilight, when the planet is near the horizon. During daylight, it reduces the brightness of the blue sky to enhance surface features. Saturn – Useful for studying bluer clouds. Venus – Use during daylight observing to reduce brightness of blue sky. Occasionally deformations of the terminator are visible.
#23A Light Red 25% T [Series 3]
All observing information for this filter is the same as that given for the #25 filter, with the exception of the following: Mars – Reduces light from blue and green areas which darkens the maria, oases and canal markings, while lightening the orange-hued desert regions. Sharpens the boundaries of yellow dust clouds. Comets – Improves definition of comet dust tails.
BLUE
#80A Light Blue 30% T [#94118-12 & Series 1]
#82A Pale Blue 73% T [Series 4]
#38A Blue 17% T [Series 3]
Moon – Enhance lunar detail. Jupiter – Enhance the boundaries between the reddish belts and adjacent bright zones. Useful for viewing the Great Red Spot. Mars – Very useful during the violet clearing. Helpful in studying surface features and polar caps. Mercury – Improve observation of dusky surface markings at twilight, when the planet is near the horizon. Saturn – Enhance low-contrast features between the belts and zones. Venus – Useful for increased contrast of dark shadings in upper Venusian clouds. Comets – Bring out the best definition in comet gas tails.
GREEN
#56 Light Green 53% T [Series 2]
Moon– Enhances lunar features. Jupiter – Increases visibility of the Great Red Spot. Useful for observing the low-contrast hues of blue and red that exist in the Jovian atmosphere. Mars – Excellent for increased contrast of Martian polar caps, low clouds and yellowish dust storms. Venus – Useful for Venusian cloud pattern studies. Reduces brightness of blue sky during daylight observing.
#58 Green 24% T [#94118-11 & Series 3]
All observing information for this filter is the same as that given for the #56 Green filter, with the exception of the following: Saturn – Enhances white features in the Saturnian atmosphere. Comets – Useful for observing brighter comets.
VIOLET
#47 Violet 3% T [Series 4]
Mars – Useful for detecting high clouds and haze over the Martian polar caps. Very useful during the violet clearing. Mercury – Helpful in detecting faint features. Saturn – Good for ring structure studies. Venus – Increases contrast of dark shading in upper Venusian clouds. Comets – Useful for observing brighter comets.
96ND FILTERS
#96ND 50% T – Density 0.3 [Series 3]
#96ND 25% T – Density 0.6 [#94118-15 & Series 2]
#96ND 13% T – Density 0.9 [#94118-16 & Series 1]
Moon – Excellent for reducing irradiation, glare and subject brightness. Colors are unaltered, as light is transmitted uniformly over the entire spectrum. Each model performs somewhat differently, depending on the brightness of the moon. Planets – Stacking in combination with color filters lowers transmission, but retains true color balance for specific applications. Reduces glare on brighter planets and minimizes irradiation. Binary Stars – Helpful in splitting binary stars, because it reduces glare and diffraction effects around the brighter star of the binary pair.
POLARIZING
[#94118-17 & Series 1]
Reduces reflected polarized light in the earth’s atmosphere. Moon & Planets – Invaluable in reducing irradiation and glare. Binary Stars – Helpful in splitting binary stars, because it reduces glare and diffraction effects around the brighter star of the binary pair.
FILTER SETS
Celestron offers four convenient filter sets, which contain four different filters per set. Not only are these highly useful filter combinations, but they also offer an economical way to add versatility to your filter collection. Descriptions of all filters within these sets are given above.
[Series 1 – #94118-S1]
Orange, Light Blue, ND13%T, Polarizing (#s 21, 80A, 96ND-13, Polarizing)
[Series 2 – #94118-S2]
Deep Yellow, Red, Light Green, ND25% T (#s 12, 25, 56, 96ND-25)
[Series 3 – #94118-S3]
Light Red, Blue, Green, ND50% T (#s 23A, 38A, 58, 96ND-50)
[Series 4 – #94118-S4]
Yellow, Deep Yellow, Violet, Pale Blue (#s 8, 15, 47, 82A)
1¼" POLARIZING FILTER SET – #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/DUST SEAL – #93621
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, C9¼, 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 C9¼ telescopes and the reducer plate of the C11 and C14 telescopes. All additional accessories mount onto the exterior/male threads.
MOON FILTERS
Celestron’s Moon Filters are economical eyepiece filters 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 for the 1¼" filter. Transmission is about 18%.
1¼" Moon Filter [94119-A]
SOLAR FILTERS
New Celestron Solar Filters are made with Baader Astro Solarâ„¢ 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 â€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.
Solar Filter – For use with F60s & F60EQs [94131]
Solar Filter – For use with F76s [94133 ]
Solar Filter – For use with F114s and C114s [94134]
Solar Filter – For use with F70s,F80s and C80s [94135]
Solar Filter – For use with CR-150s [94136 ]
Solar Filter – For use with C102s [94138]
Solar Filter – For use with NexStar 4 [94129]
Solar Filter – For use with C5s [94139]
Solar Filter – For use with C8s [94162]
LPR FILTERS
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, and both high and low pressure sodium vapor lights. In addition, they block unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. sky glow). As a result, Celestron LPR Filters darken the background sky, making deep-sky observation and photography of nebulae, star clusters and galaxies possible from urban areas. LPR Filters are not used for lunar, planetary or terrestrial photography.
While blocking unwanted light, Celestron LPR Filters permit the transmission of more desirable wave-lengths. The wavelengths included are hydrogen alpha, hydrogen beta, doubly ionized oxygen and singly ionized nitrogen. This will improve your viewing of emission nebulae, both from urban and rural settings. Some examples of objects that will show improved contrast are: the Orion Nebula, the Rosette Nebula, the North American Nebula, the Veil Nebula and the Helix Nebula.
The latest generation of Celestron LPR Filters is made of high quality, flat, polished optical glass. These units are not laminated! With over 40 layers of coating, these filters are state-of-the-art. They’re also protected with a broadband anti-reflection coating to prevent ghosting and to improve contrast. They provide superior performance and contrast over competitive models.
Celestron Filters
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