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Astrodon

The best performing astronomy filters on the market. Step up to Astrodon Filters

A note on back-orders. There is often a long waiting list for Astrodon Filters and the best thing to do is to place your order to get on the waiting list. Back-orders are usually filled within 6-8 weeks. We have increased production and we continue to work to reduce wait times. Thank you for your patience.

Astrodon is known for designing the best performing, most durable filters for astrophotography and research.

For astrophotography, Astrodon LRGB filters simplify imaging by allowing you to take one exposure time for each color, only one corresponding dark exposure time and nearly equal color combine weights in post-processing. The resulting color balance is superb, which is why so many of the top imagers now use Astrodon LRGB filters. These designs eliminate halos around bright stars that detract from the beauty of the galaxy or nebula.

Astrodon  Narrowband filters set the highest, consistent performance level, and are spectrally narrower than most other filters, leading to the best contrast and faintest structures in your nebula. Astrodon has a performance guarantee of >90%T at the emission line on every box.

UVBRI and Sloan PHOTOMETRIC filters are 100%-coated using no colored glass for long-term durability that is so critical for consistent, long-term research. They have the highest throughputs available for better signals and fainter objects and are becoming widely accepted in professional observatories in sizes up to 150mm. Some of these larger filters are used on the famous Palomar 200″ telescope, at the MacDonald Observatory, Las Cumbres Observatory of Global Telescopes, AAVSO and universities and research organizations worldwide.

All Astrodon astrophotography filters are manufactured in the U.S. with superb quality control using 100% hard-oxide sputtered coatings. Astrodon filters cost a little more because of the benefits that their high performance and great durability provides. Filters are a critical part of telescope systems. They are the “spark plugs” that make the “engine” go. Step up to Astrodons and see the difference.

Please explore our product pages to learn more about how Astrodon’s products can help you.

  • H-α (hydrogen-alpha) at 656 nm (nanometers) is deep red in color and the most popular narrowband filter, and this 20nm H-α is the same formulation but in a wider bandpass. Hydrogen is ubiquitous in the cosmos and is present in emission nebula (North American, Pelican), planetary nebula (Dumbbell, Ring), Wolf-Rayet objects (Crescent, Thor’s Helmet) and supernova remnants (Veil). Many imagers like to present just a black-and-white H-α image of an object. It is has a beauty all by itself, like an Ansel Adams photo.
  • H-α (hydrogen-alpha) at 656 nm (nanometers) is deep red in color and the most popular narrowband filter. Hydrogen is ubiquitous in the cosmos and is present in emission nebula (North American, Pelican), planetary nebula (Dumbbell, Ring), Wolf-Rayet objects (Crescent, Thor’s Helmet) and supernova remnants (Veil). Many imagers like to present just a black-and-white H-α image of an object. It is has a beauty all by itself, like an Ansel Adams photo. However, most imagers blend their H-α data into their red RGB data to enhance structural detail while maintaining a “natural” look. Therefore, the H-α filter should be your first narrowband addition to your LRGB filters. The basic imaging set of 5 filters becomes LRGBH-α.
  • NII Filter, 3nm What about NII and H-a? This is a bit complicated. It is not well known that most H-a filters pass both H-a and NII. H-a emits at 656.3 nm and NII emits most strongly at 658.4 nm (and weakly at 653.8 nm). These are very close together spectrally. Thus, most H-a filters are wide enough (e.g. 4.5 nm bandwidth and wider) to pass both emission lines as shown for the older Astrodon 6 nm filter above. Our 3 nm H-a begins to separate both emission lines and reduces the NII contribution significantly. In this example the 3nm filter only transmits 15% at the NII 658.4 nm wavelength, whereas the H-a remains unchanged. As mentioned earlier, some objects are enriched in NII, such as planetary nebula and Wolf-Rayet bubbles. The Dumbbell Nebula, M27, is a good example. The wispy clouds in the core of M27 are dominantly NII. A tricolor narrowband image is also shown below, mapping OIII to blue, H-a to green and NII to red to produce a beautiful color image. This information provides you with a choice based upon your light pollution, desire for more detail, or simply wanting all the photons you can get out of your H-a filter.
  • The next filter to complement your LRGBH-a set is an oxygen filter. OIII (“ohthree”) emits light near 500 nm and is a blue-green- or teal-colored filter. Many of my images of planetary nebula and supernova remnants are taken only with H-a and OIII filters. They show great structural detail, but have natural colors, looking like an RGB image.
  • If you want the look of Hubble Space Telescope (HST) images, such as the famous “Pillars of Creation” (the Eagle Nebula, Messier 16), then the next filter to consider adding to your collection after H-a and OIII is the SII (es-two) or sulfur filter. The SII filter, like H-a, is a deep red filter near 672 nm. H-a, OIII and SII filters provide that Hubble look for many emission nebula. Again, tri-color narrowband imaging with these three filters can be done with the moon up, so your equipment is not sitting dormant for several weeks.
  • H-α (hydrogen-alpha) at 656 nm (nanometers) is deep red in color and the most popular narrowband filter. Hydrogen is ubiquitous in the cosmos and is present in emission nebula (North American, Pelican), planetary nebula (Dumbbell, Ring), Wolf-Rayet objects (Crescent, Thor’s Helmet) and supernova remnants (Veil). Many imagers like to present just a black-and-white H-α image of an object. It is has a beauty all by itself, like an Ansel Adams photo. However, most imagers blend their H-a data into their red RGB data to enhance structural detail while maintaining a “natural” look. Therefore, the H-α filter should be your first narrowband addition to your LRGB filters. The basic imaging set of 5 filters becomes LRGBH-α.
  • Bring Out The Faint Structures In Nebulae Astrodon Narrowband filters set a new bar of performance and durability for imaging and research. We offer 5 nm and ultra-narrow 3 nm bandwidths.
  • If you want the look of Hubble Space Telescope (HST) images, such as the famous “Pillars of Creation” (the Eagle Nebula, Messier 16), then the next filter to consider adding to your collection after H-a and OIII is the SII (es-two) or sulfur filter. The SII filter, like H-a, is a deep red filter near 672 nm. H-a, OIII and SII filters provide that Hubble look for many emission nebula. Again, tri-color narrowband imaging with these three filters can be done with the moon up, so your equipment is not sitting dormant for several weeks.
  • For placing Astrodon 50 mm diameter filters in 52 mm threaded mounts for camera lenses.
  • Astrodon Clear Filters

    $150.00$320.00
    UV-Blocked Clear filters with 395 nm cut-on (50% transmission at 395 nm) and at least 97% transmission to 1000 nm. Often purchased with our photometric filters.
  • Astrodon introduced the ExoPlanet-BB filter for use in amateur-scale telescopes to measure light curves of exoplanets.
  • This filter isolates only the hydrogen-beta line of the spectrum (486nm) in a 15nm wide bandpass.
  • SIMPLIFY YOUR IMAGING! Astrodon LRGB Gen2 E-Series Tru-Balance Filter Sets were designed for cameras containing the full-frame KAF8300, KAF3200, KAF6303, KAF16200, KAF16803 sensors, as well as most Sony and back-thinned sensors.
  • SIMPLIFY YOUR IMAGING! Astrodon LRGB Gen2 E-Series Tru-Balance Filter Sets were designed for cameras containing the full-frame KAF8300, KAF3200, KAF6303, KAF16200, KAF16803 sensors, as well as most Sony and back-thinned sensors.
  • SIMPLIFY YOUR IMAGING! Astrodon LRGB Gen2 I-Series Tru-Balance Filter Sets were designed for cameras containing the Interline KAI11002, KAI16000, sensors.
  • SIMPLIFY YOUR IMAGING! Astrodon LRGB Gen2 E-Series Tru-Balance Filter Sets were designed for cameras containing the full-frame KAF8300, KAF3200, KAF6303, KAF16200, KAF16803 sensors, as well as most Sony and back-thinned sensors.
  • UV/NIR-blocked filter used for both E- and I-Series LRGB sets. Transmits at least 97% between 400 and 700 nm. 395 nm cut-on (50% transmission at 395 nm); blocked above 705nm.
  • GUIDE YOUR TELESCOPE IN FRONT OF YOUR FILTERS NEW DESIGN!! ACCOMMODATES UP TO 2 GUIDE PORTS. MOAG means Manual Off-Axis Guider. It allows you to guide your telescope to obtain sharp, round stars by guiding in front of your filters using unfiltered light in the same optical beam as your imaging camera.
  • Astrodon MMOAG Off Axis Guider

    $875.00$1,750.00
    GUIDE YOUR TELESCOPE IN FRONT OF YOUR FILTERS NEW DESIGN!! ACCOMMODATES UP TO 4 GUIDE PORTS. MOAG means Manual Off-Axis Guider. It allows you to guide your telescope to obtain sharp, round stars by guiding in front of your filters using unfiltered light in the same optical beam as your imaging camera.
  • GUIDE YOUR TELESCOPE IN FRONT OF YOUR FILTERS NEW DESIGN!! ACCOMMODATES UP TO 4 GUIDE PORTS. MOAG means Manual Off-Axis Guider. It allows you to guide your telescope to obtain sharp, round stars by guiding in front of your filters using unfiltered light in the same optical beam as your imaging camera.
  • Standard sizes are 1.25", 31mm, 50mm round, and 50mm square. For those who want 36mm round, see our 36mm adapter. Also a limited quantity of 12mm and 25mm (call for pricing and availability). 100%-Coated for long-term durability and consistency of research with the highest throughput.
  • Standard sizes are 1.25", 31mm, 50mm round, and 50mm square. For those who want 36mm round, see our 36mm adapter. Also a limited quantity of 12mm and 25mm (call for pricing and availability). 100%-Coated for Long-Term Durability and Consistency of Research using no colored glass with the highest throughputs available.
  • ASTRODON UVENUS FILTER
    • <0.01%T 285-305 nm; <0.1%T 420 – 1100 nm
    • Image the cloud structure of Venus and Jupiter with CCD cameras on a telescope.
    • Use for general UV photography (flowers, insects, forensics).

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