- Fast Shipping, Same or Next Day: You made the commitment to purchase, now you want that new item fast, we get it! At High Point all in stock orders ship within 24 hours, pending internal credit card approval.Read more ...
- Unlimited Tech Support Forever: One of the many perks of being a High Point customer is that you get access to our tech support team forever! We are astronomers at heart and truly enjoy helping fellow amateurs achieve success in the field! Read more ...
- 30 Day Return Policy: Ordered the wrong product? Don't worry, we'll take the majority of our products back within 30 days of the purchase date.We want to get you into the observing setup that bests fits your needs. Read more ...
- Guaranteed Price Match: Call or email us if you find a better price on a product! Provide a link for our team to confirm the price and within a matter of seconds you'll have a price match providing the re-seller is within the USA and authorized by the manufacturer to sell the product of interest. Read more ...
- We're Your Connection To The Manufacturer: In the event there is a warranty issue with a product purchased from High Point, we will serve as the liaison between you and the Manufacturer. The net result is faster, more attentive service from the Manufacturer and an enhanced customer experience. Read more ...
Astrodon 3 nm H-Alpha Narrowband Filter - 1.25" Threaded Cell - HA3-27R
About Astrodon Narrowband Filters
Astrodon filters are high performing, durable filters that provide significant aid for astrophotography and research pursuits. Each filter is constructed using a highly innovative process with a single high quality 3 mm thick fused silica substrate and full hard oxide sputtered coatings. With these Astrodon Narrowband filters, imagers can count on consistently high performance, as well as a more narrow spectrum compared to most other filters for superb contrast and the ability to view the faintest nebula detail. Astrodon guarantees >90%T performance at the emission line.
Astrodon 3 nm Narrowband Filter Highlights
- Guaranteed 90%+ maximum transmission for the highest achievable performance
- 3 nm bandwidth
- 1.25" Round Mounted
- >OD 4 (0.01% transmission) out-of-band blocking
- Clear 1/4 wave substrates feature hard-oxide coatings to the edge, removing light leakage from uncoated rims
- Edge blackened to reduce reflections
- Parfocal with all other filters made by Astrodon
Astrodon 3 nm H-Alpha Narrowband Filters
Highly favored among narrowband filters, hydrogen-alpha filters for 656 nm are deep red in color. As it is the most common element in the universe, hydrogen is present in emission nebula such as the North American and the Pelican, planetary nebula such as the Dumbbell and Ring, Wolf-Rayet objects like Cresecent and Thor's Helmet, as well as supernova remnants like the Veil nebula. While many imagers are content to dsiplay a simple black and white h-alpha image of an object, most imagers will want to combine their h-alpha data with their red RGB data in order to augment structural detail while preserving a "natural" appearance. For this reason, h-alpha filters make a perfect initial narrowband extension of your LRGB filters.
Astrodon Narrowband Filters - Additional Information
Setting a new standard for imaging and research performance and durability, Astrodon narrow 3 nm bandwidth filters reduce background noise to enable enhanced contrast of emission objects. Transmittance is guaranteed to be above 90% at the emission wavelength for the highest signal available. The combination of this guarantee and filters with such spectrally narrow bandwidth assures the highest contrast possible. In fact, Astrodon's latest narrowband filters are known to attain 95-98% transmittance. Even when capturing extended 30-45 minute exposures typical of narrowband astrophotography, Astrodon Narrowband filters are still able to minimize halos around bright stars, a skill these filters are known for. Lastly, these Narrowband filters from Astrodon are edge-blackened and feature coatings to the edge of the part. This is integral to keeping the stray light as low as possible for a filter that blocks most light not in the narrow bandpass.With Astrodon Narrowband filters, it's all about the enhanced contrast. The better the contrast, the more the fainter characteristics of celestial objects are highlighted. This improves with filters that have narrower bandwidths. However, maintaining a constant signal (%T at the emission line) as the filter gets spectrally narrower can be difficult. This is what makes Astrodon's >90%T guarantee so critical as it assures that you'll be able to benefit from the enhanced contrast provided by narrower filters.