The Astronomik UHC is THE filter for visual observing.

You will enjoy using your Astronomik UHC filter because you will see more stars and more details in deep-sky-objects compared to using filters from all other manufacturers.

The Astronomik UHC (Ultra High Contrast) filter allows the transmission of nearly 100% of the radiation from both O-III and the H beta lines. Though the second window for the H-alpha-line is not intended for visual observing, it is important, if the filter is used with an electronic device. All annoying, scattered light from other wavelength sources, including local artificial light pollution, is reliably filtered out. With this strong blocking of the sky background an unexpected wealth of detail becomes visible for gas nebulae and planetary nebulae.

Main use

Astronomik UHC filters’ astounding high light transmission brings better views of deep-sky-objects even to small telescopes! The high transmission of our optical glass filters means that enough light is available to allow successful visual observations with telescopes beginning at 2" (50mm) aperture. Our Astronomik filters are optimized for use with telescope focal length f / ratios of f/4 to f/15. Transmission losses and chromatic distortions, which arise with other filters, only occur with Astronomik filters when extremely bright aperture ratios of 1:2 and more come into play. Another major advantage of our Astronomik UHC filter is the high optical quality of the filter glass. When using Astronomik UHC filters you will quickly notice the same needle-sharp stars which you are familiar with from your astronomical instrument without any filter!

Suitability

• Visual observation (dark skies): Very good, for telescopes of all apertures and high exit pupil
• Visual observation (urban skies): Very good, for telescops from 100 mm aperture
• Film photography: Reasonable, but very long exposure time
• CCD photography: Good, when used with an additional IR-block-filter
• DSLR photography (original): Good, colour balance shifted but contrast enhanced
• DSLR photography (astro modified): Very good, colour balance is near perfect
• DSLR photography (MC modified): Good, when used with an additional IR-block-filter
• Webcam / Video (Planets): Unsuitable
• Webcam / Video (Deep Sky): Good, if light pollution is a big problem

Technical Data

• typ. 95% transmission at 486nm (H-beta)
• typ. 95% transmission at 496nm (OIII)
• typ. 95% transmission at 501nm (OIII)
• typ. 95% transmission at 656nm (H alpha)
• optimum position of transmission for telescopes with focal ratios from f/10 to f/3,5
• Entire Blocking of annoying wavelengths
• Ideal All-round Deep Sky filter even for small telescopes
• Not sensitive to humidity or aging
• Scratch-resistant!
• Excellent carrier material. The optical performance of your telescope is not reduced by the filter in any way.
• Parfocal with other Astronomik filters
• Glass thickness: 1mm
• Completely resistant against high humidity, scratches and aging effects
• Diffraction limited, the filter will not reduce the optical performance of your telescope!
• Astronomik filters are delivered in a high-quality, long lasting, filter box

Colour eyepiece filters are essential for observing the moon and planets. They effectively reduce glare and light scattering, improve contrast through selective filtration, and enhance definition and resolution.

Bintel's filters are constructed with top-notch, uniform glass and are coated to minimize reflections and ghosting. They are threaded to fit 1.25" eyepieces and provide a generous 26mm clear aperture.

#12 Yellow Filter

The #12 yellow filter enhances Jupiter’s cloud bands, particularly the lighter zones and the Great Red Spot, improves Mars' surface details, such as polar ice caps and dust storms, and sharpens contrast on the Moon, highlighting the maria and highlands.

#15A Dark Yellow Filter

The #15A dark yellow filter improves contrast on Jupiter's cloud belts, especially in the darker equatorial regions and the Great Red Spot, reveals surface features on Mars such as ridges and valleys, and enhances the details of lunar craters and shadows along the terminator.

#21 Orange Filter

The #21 orange filter helps define the atmospheric cloud structures on Jupiter and Saturn, enhancing features like the Great Red Spot and Saturn’s cloud bands, sharpens the visibility of Mars’ dust storms and polar ice caps, and brings out lunar surface details, particularly in shadowed areas.

#23A Light Red Filter

The #23A light red filter enhances the contrast of surface features on Mars, such as ice caps, dust storms, and topography, improves the visibility of Jupiter’s cloud belts and storms like the Great Red Spot, and highlights the Moon’s surface features along the terminator, including craters and maria.

#29 Dark Red Filter

The #29 dark red filter significantly enhances the contrast of Mars’ surface features like its ice caps, dust storms, and valleys, brings out darker regions and bands in Jupiter's atmosphere, and improves lunar contrast, especially in low-light areas and the terminator.

#38A Dark Blue Filter

The #38A dark blue filter enhances Jupiter’s cloud details, especially the lighter and darker zones and the Great Red Spot, improves the visibility of cloud layers on Saturn, and helps to bring out surface features such as the polar ice caps as well as dust storms on Mars by enhancing atmospheric contrasts.

#47 Violet Filter

The #47 violet filter brings out atmospheric features on Jupiter, such as cloud bands and storm systems, enhances the visibility of cloud layers on Saturn, and improves the contrast of Venus' upper atmosphere, revealing subtle cloud structures and atmospheric patterns.

#58A Dark Green Filter

The #58A dark green filter increases contrast in Jupiter’s cloud bands and atmospheric details, such as the Great Red Spot and polar regions, enhances Saturn’s ring details and cloud structures, improves the visibility of Mars’ surface features like polar ice caps and dust storms, and sharpens Venus’ cloud patterns.

Adjust the brightness level of the Moon, Venus, and other bright objects with the Optolong Variable Polarizer. A standard Moon Filter is similar to a pair of sunglasses. They work fine, but sometimes the scene is too dark or too bright, and there’s not a lot you can do about it. A variable polarizing filter is much more flexible than a Moon filter. It allows you to set the percentage of attenuation by turning the top section of the two-piece filter. Simply attach the 2" threaded filter to a like-sized eyepiece or Astro accessory barrel, and then slowly rotate the top half of the filter—it turns 360°—to achieve the results you desire.

The Optolong Variable Polarizing Filter also works great to cut brightness when you are using your telescope for terrestrial observations or photography. If you have ever done photography through a SLR or DSLR camera, you may have already been introduced to the qualities of a polarizing filter, since it is a very popular accessory for polarizing the light and making the sky appear bluer. You will especially appreciate a polarizing filter when viewing over water or photographing a scene that includes a river or body of water. Simply turn the filter until you achieve the most glare-free results—you will really see the difference.

From the start, the Astronomik OIII filter has been very specifically designed for the visual observation of gaseous and planetary nebulae. The extremely narrow pass band of the two OIII lines brings a substantial contrast gain to these lines even under best observation conditions. On faint super nova remnants and faint planetary nebulae the Astronomik OIII filter will often make the difference as to whether the object can bee seen or not!

The optimal aperture ratio for the use of the filter is 1:3.7 to 1:15 with apertures of more than 6" (150mm). Transmission losses and chromatic distortions, which arise with other filters, occur with Astronomik OIII filters only when extremely bright aperture ratios of 1:3 and more come into play. The Astronomik OIII filters thus can expand the view of dispersed objects, generally speaking, to the whole visual field of view of the eyepiece and are not limited to only the center of the eyepiece.

Main use

Since enough light must be available to make use of the OIII filter it is best to use this filter with apertures of more than 6" (150mm). Smaller instruments do not gather enough light for meaningful and satisfying astronomical work. However, please note: Many experienced Deep Sky observers, with apertures of more than 10" (250mm), prefer using the OIII filter instead of the more versatile UHC filter. Due to the high optical quality of the Astronomik OIII filter substrate you will see the same needle-sharp stars as you would from your regular telescope.

The UHC-E Filter increases contrast of emission nebulae and comets and blocks the light of typical streetlights as well as airglow. It is best suited for telescopes up to 5" / 125mm.

Main use

The Astronomik UHC-E filter provides a FWHM of 45nm and blocks the light of typical streetlights (e.g. sodium and mercury vapour) as well as airglow. Thus it increases contrast between your target and the night sky. The contrast enhancement is less than that of the Astronomik UHC filter, but at the same time the transmitted amount of starlight is greater. It's therefore better suited to smaller telescopes. As the UHC-E filter passes a spectral line of Carbon (due to the higher FWHM) it opens up the possibility of comet observation.

Other uses

• Observation of Jupiter’s clouds.
• Easier resolution of Double Stars.
• Photography under light-polluted skies with DSLRs and other cameras.

Suitability

• Visual observation (dark skies): Reasonable, an UHC filter is more suitable
• Visual observation (urban skies): Good, for telescopes up to 125 mm aperture and medium exit pupil
• Film photography: Good, but very long exposure times
• CCD photography: Good, when used with an additional IR-block-filter
• DSLR photography (original): Good, colour balance is near perfect
• DSLR photography (astro modified): Good, colour balance is near perfect
• DSLR photography (MC modified): Good, when used with an additional IR-block-filter
• Webcam / Video (Planets): Unsuitable
• Webcam / Video (Deep Sky): Very good, if light pollution is a big problem

Technical Data

• typ. 94% transmission at 486nm (H-beta)
• typ. 95% transmission at 496nm (OIII)
• typ. 95% transmission at 501nm (OIII)
• typ. 94% transmission at 656nm (H alpha)
• transmission 465nm to 530nm and above 645nm 
• Full width at half maximum 45nm
• Parfocal with other Astronomik filters
• Glass thickness: 1mm
• Completely resistant against high humidity, scratches and aging effects
• Diffraction limited, the filter will not reduce the optical performance of your telescope!
• Astronomik filters are delivered in a high-quality, long lasting, filter box
• Since 2008 we do ship filters with a completely new design. Any kind of halo or strange reflection is a matter of past