Otis AstroImaging: Filters

Astronomical Filters Directory & Library
This filters directory and library includes telescope filter information and the covetous spectral data sheets, when available, for developing applications

SVBONY CITY LIGHT SUPPRESSION CLS (ABOVE)

https://www.svbony.com/cls-filter

The bandwidth of Svbony CLS Filters is wider than that of Svbony UHC Filters, and the luminous flux is large, which is more suitable for use in places with less light pollution. The SVBONY City Light Suppression broadband filter is designed to improve the visibility of various Deepsky objects. By selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lightings including mercury vapor lamps, both high & low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). Together with the highly transparent in main nebula emission lines at OIII(496nm and 500nm), H-beta (486nm), NII(654nm and 658nm), H-alpha(656nm) as well as SII(672nm), the Svbony CLS filter is suitable for enhancing the contrast and details for both visual and photographic purpose at sub-rural area. 1. Brand: SVBONY 2. Type: City Light Suppression Filter (CLS Filter) 3. Material: Optical glass lens, Aluminum Frame 4. Shape: Round 5. Barrel diameter: 1.25'' (Thread size: M28.5*0.6mm) or 2" (Thread size: M48*0.75mm)

SVBONY 1.25" MOON & SKYGLOW (ABOVE)

SVBONY 1.25" moon and skyglow filter is a multi band pass filter transmitting a high percentage of light in the visual spectrum; the filter enhances contrast when observing brighter objects including the moon and planets. Telescope eyepiece cutting light pollution; the filter has a mild effect of darkening the background of the night sky so that the fainter objects are more clearly seen contrasted against the blackness of space. The filter effectively filters out selective wavelengths of low pressure sodium and other man made sources typically used in street lighting; although it is not a nebula filter; it enhances the views of deep sky objects by increasing the contrast of these objects against the background sky

https://www.amazon.com/SVBONY-Astronomy-Telescope-Thread-Pure-Pollution/dp/B071CTYTQS 1.25" moon and skyglow filter is a multi band pass filter transmitting a high percentage of light in the visual spectrum;the filter enhances contrast when observing brighter objects including the moon and planets. Telescope eyepiece cutting light pollution;the filter has a mild effect of darkening the background of the night sky so that the fainter objects are more clearly seen contrasted against the blackness of space. The filter effectively filters out selective wavelengths of low pressure sodium and other man made sources typically used in street lighting;although it is not a nebula filter;it enhances the views of deep sky objects by increasing the contrast of these objects against the background sky. Premium quality metal rim and thread with blue glass lens;the filter will fit all standard sized 1.25" eyepieces and accessories;it is mounted in a nicely anodized housing and is threaded on both sides for stacking with other filters if necessary. Standard filter thread for any 1.25” telescope eyepiece and other accessory;comes with a plastic box to keep it safe and clean when not in use; It's mainly used for visual and photography of the planets, which can effectively suppress the interference of the sky's glow (589nm) and improve the contrast of planets. Graph not available.

SVBONY 1.25'' LINEAR POLARIZING FILTER

SVBONY 1.25'' Polarizing Filter Linear for Telescope Astronomy & Eyepiece Increasing Contrast Reduce Glare Increase Detail. The Svbony 2" Polarizing Filter is high quality anodized aluminum, optical glass polarizing filter designed to reduce the amount of light entering your eyepiece. You can progressively dim the view when observing a bright object, such as the Moon or certain planets, to a level according to your needs, while increasing contrast, reducing glare and increasing the amount of detail that can be studied. The 2" Polarizing Filter is the best all-purpose lunar and planetary filter.

SVBONY CPL CIRCULAR POLARIZER LINEAR (ABOVE)

The Svbony 1.25-inch variable Polarizing filter acts like a dimmer switch for your telescope. A CPL filter – which stands for circular polarizer/linear – is a glass attachment that can reduce the glare from reflected surfaces. It does this by taking what you could call “obstacles,” such as unwanted light, reflections or color, and reducing them to a certain extent. Adjusts the amount of light transmission from 1% to 40% by rotating the filter housing. Reduces brightness of the Moon or planets for great clear viewing. Finer control of the image brightness compared to a standard fixed-transmission telescope filter for optimal performance. Fit standard sized 1.25" eyepieces and accessories. Premium quality metal rim and optics glass lens. Sturdy plastic case included. Model: SV128. Type: Variable Polarizing Filter. Material: Optical glass lens + Aluminum Frame. Shape: Round. Barrel diameter: 1.25''. Thread Standard: M48*0.75. Weight: 1.258g / 0.99oz. The Svbony 2" Polarizing Filter is high quality anodized aluminum, optical glass polarizing filter designed to reduce the amount of light entering your eyepiece. You can progressively dim the view when observing a bright object, such as the Moon or certain planets, to a level according to your needs, whilst increasing contrast, reducing glare and increasing the amount of detail that can be studied. The Polarizing Filter is the best all-purpose lunar and planetary filter.

SVBONY UV/IR CUT (ABOVE)

The SVBONY UV/IR cut filter has a very high transmission rate, improved over most other brand filters. Example: use with the Zwo ASI224MC color camera to maintain color balance and sharp imagery. The filter passes visible light and blocks high frequency ultraviolet and low frequency infrared. Optical glass with low reflection coatings. Interface threads are M28.5x0.6.

ZWO ASI224MC CAMERA WINDOW (ABOVE)

Both cameras, ASI120MM and ASI224MC, have a clear, IR transmitting, protection filter in front of the chip to keep dust off the sensor. This is normal for a mono camera like the 120MM, where you might want to also use IR and UV filters, but not so for an OSC camera like the ASI224MC. OSC color cameras normally have an IR/UV filter rather than a clear glass because their sensitivity in the IR is poor. The ASI224MC, however, can actually image into the near IR with 30% transmission at 900nm and in fact behaving essentially as a monochrome IR camera in the range 825nm – 1000nm.

ASTRONOMIK PROPLANET IR 742 (ABOVE)

The ProPlanet IR 742 only allows infrared light with wavelengths of more than 742 nm to pass. In this wavelength range the effects of seeing are significantly lower than in the visible spectrum of the human eye. This allows much sharper images than are usually obtained from your device and location. Another advantage is that the sky background of advanced dawn is dark and so the filter even allows photography of the planets and the Moon at daylight. Main use: The Astronomik ProPlanet IR 742 cuts off the visible part of the spectrum and allows the light of wavelengths longer then 742nm to pass. Due to this behavior, the part of the spectrum that is most sensitive to bad seeing is rejected. This approach does a big improvement to the imaging of planets and the moon. The image is more steady than the image in the visible light with nearly identical exposure times. Darkens the background during twilight. Imaging of bright planets, stars and comets by day. Imaging of young stars in dust clouds and stellar nurseries. Alternatives. When the seeing is very bad and the instrument is 10" (250 mm) or larger, the Astronomik ProPlanet IR 807 may be the better choice. Webcam / Video (Planets): Very good, rejects problems with seeing. Webcam / Video (Deep Sky): Very good, rejects problems with seeing. more then 96% transmission for wavelengths of 742nm to 1100nm. blocking of wavelengths between 350nm and 730nm.

ZWO Ha H-Alpha 7nm 1.25" (ABOVE)

Narrowband filter does not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.,It can reduce the transmission of certain wavelengths of light, specifically those produced by artificial light including 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. skyglow). The ZWO H-Alpha filter has a bandpass of 7nm and passes light at 656nm wavelength, light transmission rate comes up to 80%. Narrowband H-alpha astrophotography filter for high-contrast imaging and revealing rich details of the nebula even in areas with strong light pollution.

ZWO 1.25″ IR 850nm Pass (ABOVE)

Suitable for IR sensitive cameras. You don’t need to debayer and get the full resolution of this sensor when using it with a Color camera such like ASI224MC or ASI185MC, because the QE response of the sensor beyond 850nm is all the same. So you can use a color camera as mono camera with this filter, just don’t forget to keep the WB_R and WB_B to 50 (no White Balance applied).

ZWO LRGB SET (ABOVE)

Designed to approximately equalize the flux of ASI1600 mono sensor, Schott substrate material, glass thickness 1.1mm, polished accurate 1/4 wavefront, 90% transmission at passband, infrared wavelength 700-1100nm cut-off, precision off-band blocking, multi-layers anti-reflection coating

ZWO 1.25″ IR UV CUT (ABOVE)

Suitable for color camera with AR protect window, blocks infrared light from reaching the sensor of your CMOS camera or H-alpha filter. When imaging, the addition of this simple and inexpensive accessory will result in sharper images, and when doing solar work, the IR Cut Filter will your protect H-alpha filter from the damaging effects of infrared radiation. Infrared or IR light is invisible to the human eye, and so even though most telescopes are not designed to focus IR light, it does not matter when you are using your telescope visually. However, when you add a camera to the mix, it's a whole other story! Unlike the human eye, a silicon sensor is very sensitive to light in the infrared portion of the spectrum, and that is a problem because infrared images are blurry as all get out. That means your nice, sharp visual light image is degraded by the addition of the infrared layer. This problem can easily be solved by blocking the infrared, and the ZWO IR Cut-Off, will do just that.

Optolong L-Pro (ABOVE)

For light pollution. Best used for imaging most emission nebulae, reflection nebulae, and dark nebulae. Suitable for both visual and photographic observations. Effective in suppressing light pollution sources. This is a true broadband filter that aims to preserve the natural colors of stars in the night sky. It includes a mild filter against known sources of artificial light including LED street lights. Designed to improve the visibility of various deep sky objects. By selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lights including mercury vapor lamps, both high and low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). Together with the highly transparent in main nebula emission lines at OIII (496 nm and 500 nm), H-beta (486 nm), NII (654 nm and 658 nm), H-alpha (656 nm), as well as SII (672 nm), the filter is suitable for enhancing the contrast and details for both visual and photographic purpose at sub-rural area with heavy light pollution. Unlike other light pollution filter UHC and CLS, L-Pro is multi-bandpass filter which offers better color balance by maximizing the transmission band. The balanced transmission allows astrophotos to be taken with minimal color cast to broadband emission objects such as galaxies, reflection nebulae and globular star clusters. L-Pro is the best choice for light pollution suppression.

Works well on most emission nebulae, reflection nebulae and dark nebulae. Suitable for visual observation and astrophotography, has a very low transmission reduction rate against continuous spectrum space objects, and thus is quite effective in suppressing light pollution sources when shooting galaxies, reflection nebulae and globular star clusters. The same holds true for visual star observations.

L-Pro filter alone suppresses infrared wavelengths, and thus can be used at ease for "L" image shootings with CCDs. Light pollution filters do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.

Optolong UHC Ultra High Contrast (ABOVE)

Light pollution filter for use in severely light polluted urban area. It selectively enhances emission from nebulas and suppresses the transmission of light pollution sources. UHC enhances the transmission of nebulas emissions and reduce background brightness mostly dominated by light pollution. It has narrower passband than CLS (City Light Suppression) and thus it is the better choice of imaging under severely light polluted areas due to its more rigorous light pollution suppression. Its wider passband towards the red end of the visible spectrum makes it exceptionally suitable for hydrogen emission dominated objects such as M42 Great Orion Nebula. UHC selectively cuts out light pollution emission. For example, mercury vapor lamps, high and low pressure sodium vapor lights and skyglow caused by emission from neutral oxygen in our atmosphere. Among the emission lines enhanced are OIII (496, 500nm), H-beta (486nm), NII (654, 658nm), H-alpha (656nm) and SII (672nm).

Highlights: 95% transmission at major nebula emission lines, 0.1% transmission at off-band at Na (589nm), Hg (435nm, 578nm), multi-layers anti-reflection coating, Precise and sharp roll-off at light pollutant lines, 2 mm filter thickness (1.25", 2" and 77mm) | 1mm (clip series), made on Schott substrate, finely polished to 1/4 wave accuracy, surface quality: 60/40 (MIL-O-13830 standard), equivalent to OD3. Recommended applications: Monochrome & one-shot-colour CCD/CMOS camera, Deep sky colour imaging, particularly emission nebula or DSO emitting in the H-alpha, H-beta, O-III and S-II lines. The Optolong UHC (Ultra High Contrast) broadband filter is designed to improve the visibility of various deep sky objects. It does this by: Selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lighting (including mercury vapor lamps, both high & low pressure sodium vapor lights, and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). Being highly transparent to the main nebula emission lines at OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha(656nm) as well as SII (672nm).

Main Feature: 1.25" astronomy filter with standard M28.5x0.6 male filter thread (no female thread, so it cannot be stacked with other filters). Ultra-thin filter cell to minimize vignetting; clear optical aperture of 26mm. Precision CNC-machined metal filter cell with sand blasted black anodized finish, anti-reflection treatment, and laser engraving. Suitable for enhancing the contrast and details for both visual and photographic purpose at urban and suburban areas with heavy light pollution. Suitable for color CCD cameras and unmodified DSLRs.

UHC has a narrower passband and thus provides higher contrast than a CLS (City Light Pollution / Light Pollution Reduction) filter. Thus it is more suitable for urban environments where you suffer from severe light pollution. UHC has a substantial red passband and offer superb views of objects like the Orion Nebula (M42). Spectral Curve Transmission Characteristics: 95% transmission of main nebula emission lines: H-beta 486.1nm, OIII 495.9nm and 500.7nm, H-alpha 656.3nm, and SII 672nm. 0.1% transmission of major transmission lines of artificial light pollution: Hg (Mercury) at 435.8nm, 546.1nm, 577nm, and 578.1nm. Na (Sodium) at 598nm, 589.6nm, 615.4nm, and 616.1nm. Technical Specifications: Both surfaces are fine optically polished, accurate to 1/4 wavelength or better, and parallel to within 30 seconds or arc. 2mm thick Schott B270 optical glass substrate material. Very high surface quality of 60/40 or better (US Military Spec MIL-O-13830). Optical Coating Specifications: multi-layer anti-reflection coated, non-cementing optical substrate coating. Electron-beam gun evaporation with Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL (central wavelength) so that there is no deviation due to temperature changes during us

SVBONY SV164 Dark Frame Imaging Filter 1.25-Inch (ABOVE)

Eliminate Camera Noise and Hot Pixels Black SV164. Pesky camera noise can leave distracting bright spots and unwanted fixed patterns on your captured exposures. Dark frame acquisition helps remedy such noise and "hot pixels" by canceling out these disruptive effects during image processing. This handy filter ensures your acquired dark frames will be completely free of unwanted stray light and reflections for great results. Capture dark frames quickly to optimize photo quality. Easily eliminate camera noise and hot pixels. Opaque filter blocks all light from imaging camera sensors. The 1.25" Dark Frame Imaging Filter is threaded for direct attachment to filter wheels.

Svbony 1.25" LRGB Set SV127 (ABOVE)

#15 Deep Yellow

#25 Red, better red filter goes into IR

#58 Green

#80A Medium Blue

Svbony SV183 IR Pass 685nm 1.25" (ABOVE)

Blocks wavelengths below 670nm to enhance contrast and surface detail and reduce the effects of seeing when used in IR-LRGB imaging of the moon and planets. Sufficient reduction of seeing effects; heightened contrast; the Filter can darkens the twilight sky background allowing images of moon and planets to be taken at dawn or dusk. In addition to astronomical uses, the IR-Pass filter can be used for nature photography in the Near-IR; revealing stunning differences in plants; sky and cloud. Atmospheric seeing and distortion diminish as you move further away from visible light into the infrared, and since CCD and CMOS sensors are sensitive to IR light, imaging in the infrared will improve your results.

95% transmission at bandpass. The SVBONY IR Pass 685nm Filter is made with Schott glass that has been multi-coated with an ion-assisted deposition technology to ensure scratch resistance and stability on the central wavelength, or CWL. The filter cell is made of lightweight, strong metal and is CNC machined, sand-blasted, black anodized, and then laser engraved. The result is a super thin filter cell that will produce a clear aperture of 45mm. Tip for use: Ideal for imaging, use for the luminosity channel. The normal spectral bandwidth is 400-700nm. This filter starts at 670nm in the deep red, just in the visual range so it can be focussed correctly. At this long-wavelength spectral range the atmospheric air turbulence (seeing) has much lower impact on the sharpness. Dark structures on Mars, Jupiter the Moon and the Sun are thereby rendered much sharper. The luminosity can then be combined with RGB creating a very sharp LRGB image.