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Emission Line (Narrowband) Filters

The new series of Astronomik MFR Narrowband-Emissionline Filters is perfect matched to the requirements of astronomical Deep-Sky imaging. For the three most important emission lines of Oxygen (OIII), Hydrogen (H-alpha) and Sulfur (SII) you may select your filters eitherwith 12nm or 6nm Bandwidth (FWHM).

Our new filters are made in a completely new construction, which makes the best Out-of-Band blocking possible across the whole range of wavelengths from the UV up to IR! Your advantage of our new design is a extremly high contrast, minimized stray light, no halos and needle-sharp stars. With the new Astronomik MFR Narrowband-Emissionline filters you get data with the best quality possible: The best starting material to be processed to a awesome final image!
To get the maximum from the valuable observation time you need filters with the highest transmission possible. We do guarantee a transmission of 90%, but typically the transmission is as high as 96% . -These values are valid for the 12nm and the 6nm filters as well!
For maximum contrast the SII filter is carefully designed to block all light coming from H-alpha and NII (nitrogen).

Due to the new MFR coating the new Astronomik Narrowband filters can be used at nearly all instruments and safe you money:
Contrary to filters from other manufacturers the transmission curve of the new Astronomik Narrowband-Emissionline filters is nearly not shifted when used with fast optical systems! While other manufactures sell special "High Speed" filters or you even have to buy a new filter for each scope, this is not the case with the new Astronomik Narrowband-Emissionline filters with MFR coating. Save lot´s of money as you may use all filters with 12nm Bandwith (FWHM) with any instrument up to f/3 and all 6nm filters up to f/4!

Imaging with Narrowband-Emissionline Filters
If you have to observe from light polluted sites (like most of us...), imaging with Narrowband-Emissionline filters is the best way to take great images, as all kind of light pollution can be blocked very effective! Normaly an H-alpha filter should be your first step into this amazing field of astrophotography! With an Narrowband H-alpha filter you will be able to take deep and contrasty images even wih very heavy light pollution or with the full moon high up in the sky!
If you look at other astrophotos, an H-alpha is the best choice for all nebulas glowing red! An OIII filters expands your imaging possibilities, as you are able to image all greenish/blueish structures. Planetary nebulas and star forming regions are great targets! The SII filters completes your HSO-set of filters. With these three filters you are able to process your images like the ones from the Hubble space telescope!
The h-beta filter is not available in a 6nm version, as this filter has nearly no meaningfull application. To illustrate this, there are two images shown below: Both were taken with a unmodified Canon 650D. Even as the camera has a sensitivity of less than 10% at H-alpha, there is some signal und structure in the h-alpha image, while you cannot see anything on the image taken with an H-beta filter!

Quality aspects of the new Astronomik MFR Narrowband-Emissionline Filters:

  • MFR Coating: The 12nm Filters can be used on all instruments up to f/3, the 6nm filters up to f/4. (Filters for faster optics are available upon request.)
  • High-Quality substrate: Astronomik filters are made with stress- and striae free, opticaly polished glass. The filter itself is made of ultra thin layers on this substrate!
  • Parfocal filters: All Astronomik Filters are parfokal! Due to the very small thickness-tolerance the focal plane is not shifted when changing filters! We have supplied parfocal filters for optical system as fast as f/1!
  • Coating: Astronomik filters are made of up to 130 layers which are coated on both sides of the substrate. These layers form the filter itself and act as a Anti-Reflection Coating.
  • Durability: Due to our coating technique all Astronomik filters are highly scratch resistant, not sensitive to moisture and do not degrade when getting older. -Every Astronomik filter will deliver it´s full perfomance and meet the specs at the point of shipping even after lot´s of years.
  • Integated Blocking: All unwanted light is blocked in the whole spectral range from UV up to the IR! (You will not need an additonal UV & IR-Blocker when imaging with the new Narrowband-Emissionline Filters with MFR coating!)
  • Wide range of available sizes from 1,25" up to square 50mm x 50mm filters.
  • Delivered in a high-quality Protection & storage box.
  • Due to our outstandding Coating technique we do offer a 10 year guarantee on all of our filters. (Check some forums, we REALLY do so!)

You get the highest quality possible with every single Astronomik filter to be able to take perfect images with your instruments! Especialy the filters against Lighpollution and the Narrowband-Emissionline filters will expand your imaging possibilities enormous! You are investing your money for an accessory which will work in lot´s of years in the same ways it did when it was brand new. Due to our special coating technique the filters do not degraed when getting older, and due to the new MFR coating you will be able to use the filter on nearly all instruments!

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Astronomik H-alpha CCD Filter

Astronomik H-alpha CCD FilterFrom:  £116.00

This H-alpha Filter is suitable for imaging of Hydrogen nebulas from observation sites with light pollution and from dark sites as well.

Astronomik H-Beta CCD Filter

Astronomik H-Beta CCD FilterFrom:  £116.00

Astronomik H-Beta Visual Filter

Astronomik H-Beta Visual FilterFrom:  £89.00

The Astronomik H-beta is a filter for visual observation, in particular with instruments of larger aperture.

Astronomik OIII CCD Filter

Astronomik OIII CCD FilterFrom:  £116.00

This Astronomik OIII-CCD Filter is suitable for imaging of OIII nebulas from observation sites with light pollution and from dark sites as well.

Astronomik SII CCD Filter

Astronomik SII CCD FilterFrom:  £116.00

The SII filters completes your HSO-set of filters. With these three filters you are able to process your images like the ones from the Hubble space telescope!

Baader CMOS Optimised 5.5nm H-Beta Narrowband Filters

Baader CMOS Optimised 5.5nm H-Beta Narrowband FiltersFrom:  £159.00

A new CMOS Optimised H-Beta filter from Baader Planetarium

Pegasus Astro 2'' Narrowband Filters

Pegasus Astro 2" Narrowband FiltersPlease Call to Confirm the Price


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Typical questions asked by customers looking for Narrowband-Emissionline Filters:

    Which Full-Width-Half-Maximum is the best one for me? 12nm or 6nm?

The question which Full-Width-Half-Maximum (FWHM) is the "best", shows up on in eMails on our monitor or when talking to customers at fairs very often. A general "right" or "wrong" or "best" does not make any sense. -We would not offer both series if they were not needed.
When imaging from the city/suburb the images taken with DSLRs and most CCD cameras are limited by the dark current of the sensor and not by the brightness of the sky background. In this case you will not see fainter structures when using a 6nm filter instead of the 12nm version. Additional to that cameras with an integrated guiding sensor will get more stars for guiding with the 12nm filters!
If you have a camera with an extremly low dark current and effective cooling, the 6nm filters will give you major advantages: Due to the stronger blocking of the background you will be able to expose longer and get deeper images! All stars are very tiny points, most faint stars do not show up anymore! -This is a major advantage even for normal cameras, as you can take images of faint structures even in star-crowded regions of the milkyway!
To put it short: 12nm Filters are the right choice for all DSLRs and dark-current limited cameras.
6nm filters are the best choice for observing sites with extrem strong light pollution, cameras with low dark-current and when weak objects require the maximum contrast and star-reduction possible!

    How much is exposure time increased?

This question is asked quite often, and the answer is very easy: You don have to expose longer, but you MAY expose longer!
Due to the high transmission of approximately 100% at the center wavelength nearly all these photons reach the sensor. So the number of fr example "H-alpha-photons" does not change significant wether a H-alpha filter is installed or not. But looking at the photons of other wavelength, which wi do NOT want to record makes the effect of the filter clear: The combination of a very good blocking of all unwanted light from UV up to the IR and the narrow bandwidth of the filters reduces all unwanted signal on the sensor! If you do an exposure of 30sec without any filters from a lightpolluted urban observing site, your sky-background might be allready very, very bright or even saturated. The same image taken with an Narrowband-Emissionline filter will give you a perfect black background without any signal and the signal from the object will be about the same. With this black background you have the possibility to expose longer -propably 30min instead- to record fainter structures! So itś not a "must", it´s a "may".



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Telephone: 01353 776199 or 07990 646466

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