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LPR & Nebula Filters

ScopeTronix IR Blocking Filter

   Webcams do a great job of imaging, but they are too sensitive in the IR range. The original lens on your webcam contained an IR filter but that lens must be removed for best use with a telescope. Without an IR cutoff filter IR light can overwhelm the sensor causing blooming and over exposed areas of the image. These quality IR cutoff filters block the IR from your CCD chip allowing you to take better images with the proper exposure based on visible light. They have standard 1.25" filter threads so they thread directly into the bottom of our webcam adapters (or into the bottom of 1.25" eyepieces for eyepiece projection astrophotography). Also useful for other CCD imagers.

Meade #1A Skylight Filter/Dust Seal

   The #1A Skylight Filter threads onto the rear cell of all Meade LX-Series telescopes and effectively seals the interior of the telescope from dust. All other rear cell accessories may then be threaded to the #1A filter. The filter increases visual and photographic contrast, decreases glare, and helps to penetrate haze.

Meade Series 4000 Broadband Nebular Filters

   Technical Basis of the Meade Broadband Nebular Filter: As shown in the transmission graph below, the Meade Broadband Nebular Filter strongly rejects the light of sodium- and mercury-vapor lights as well as natural airglow and auroral emissions. Conversely, the strong nebular emission spectral lines, transmitting in the visually sensitive regions primarily at 486nm (Hydrogen filter with high transmission percentages. The effect of the filter is that nebular light reaching the eye is observed visually in dramatically increased detail, while the effects of unwanted city lights are greatly reduced. The Meade Broadband Filter also passes photographically-important Hydrogen Alpha nebular light at 656nm largely unattenuated, making the filter a valuable aid in the photography of deep-space emission nebulae as well. The contrast between galaxies and the night-sky backdrop is also typically enhanced by the filter, but because galaxies emit light in a much broader range of wavelengths than nebulae, the effect is generally not as dramatic in these cases.

Meade Series 4000 Narrowband Nebular Filters

   Unlike the wide transmission band characteristics of the Broadband Nebular Filters, Meade Narrowband Filters zero in on the three most important visible wavelengths emitted by deep-space emission nebulae: the two spectral lines of Oxygen III at 496 and 501nm and the Hydrogen Beta line at 486nm. Virtually all unwanted city light emissions are rejected by factors of 99.9+%. Because of its narrow bandpass characteristics, the Narrowband Nebular Filter achieves striking levels of contrast between the nebula itself and the surrounding dark-sky environment: objects such as the Orion Nebula (M42), the Lagoon Nebula (M8), and the Omega Nebula (M17) are observed as they would normally appear through telescopes of several inches larger aperture. Tenuous, faint outer extensions of these objects now become readily observable, often to the point where the visible mass of the nebula is more than doubled in diameter. Planetary nebulae such as the Ring Nebula (M57), the Dumbbell Nebula (M27), and the Saturn Nebula (NGC7009) similarly display dramatically-heightened levels of contrast and observable detail. Faint, insignificant patches of nebulosity that heretofore were near the limit of observability are now viewed with ease.

   The Meade Narrowband Nebular Filter should be viewed as a complement to, not as a substitute for, the Broadband Filter above. The Broadband Filter enhances the performance of a much wider range of nebular objects; the Narrowband Filter improves contrast and visible detail on fewer objects, but in these more limited cases it does so to a most dramatic level. Because of the very narrow range of total light energy transmitted, the Narrowband Filter is not intended as a photographic filter. Visual effects of the Narrowband Filter are most pronounced when the filter is used with eyepieces of 25mm focal length and longer.

Meade Series 4000 Oxygen-III Nebular Filters

   Meade Oxygen-III (O-III) nebular filters provide an extraordinary level of nebular filtration on diffuse and planetary nebulae. Observations of these nebulae in a city environment with the O-III filter often yield more image contrast than observations of the same objects in a dark-sky setting without the filter.

   The O-III filter extracts more than 80% of the light emanating from the two oxygen-III spectral lines at 496 and 501nm. Objects such as the Omega (Swan) Nebula (M17) in Sagittarius, the Orion Nebula (M42) in Orion, the Helix Nebula (NGC 7293) in Aquarius, and the Eagle Nebula (M16) in Serpens are revealed in dramatically increased detail. Meade 60-layer interference coating technology isolates the desirable O-III lines, while attenuating other spectral lines virtually to zero. As with Meade Narrowband Filters, the O-III Filters are complements to other Meade nebular filters; the effectiveness of each filter type is highly dependent on the physical characteristics of the particular nebula being observed.

Celestron Contrast-Booster Filter

   This is Celestron's 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.

Celestron Light Pollution Reduction (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. The 1.25" version will go directly into the bottom of any 1.25" eyepiece that is threaded to accept filters. The SCT version will thread on to the rear cell of any Schmidt-Cassegrain.

Celestron Skylight Filter and Dust Seal

   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 Schmidt-Cassegrain 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.

SmartAstronomy Filter Cases

   Just clip the case to your belt loop and have 6 of your most used planetary and nebular filters in one convenient case by your side. Made of water-proof nylon, SmartAstronomy's Filter Case has 6 clear plastic pockets, each of which can hold a 1.25", or 2" filter. Keep them clean and protected while having them accessible at your waist. Provides greater protection than individual box cases. A secure Velcro insures you won't loose them in the dark. Comes in Black, Red, and Navy blue. Case folded is 7.50" x 4".