Difference between Astronomik MFR and MaxFR coating

The MFR coating ensures that the Astronomik Narrowband-Emissionline filters can be used with nearly all instruments, saving you from having to buy different filters for different focal ratios. Unlike other manufacturers' filters, which often require special “High-Speed” versions, Astronomik’s MFR filters maintain their transmission characteristics even with fast optical systems. 

For extremely fast optical systems such as the Celestron RASA and Takahashi Epsilon Astrographs, Astronomik has developed the MaxFR coating.

Both the Astronomik MFR and MaxFR coatings give you the best out-of-band blocking over the entire wavelength range from UV to IR, extremely high contrast, minimized stray light, no halos and needle-sharp stars.

Difference between Astronomik 12nm and 6nm filters

The choice between 12nm and 6nm FWHM filters depends on your imaging conditions and camera type. There is no universal "best" option - each FWHM serves a specific purpose.

The 12nm Astronomik Narrowband-Emissionline filters are better suited for use with typical DSLR cameras with CMOS sensors and CCD cameras with normal or high dark current or if you are observing from suburban or dark-sky locations. They are also the preferred choice for cameras with an integrated or dual guiding sensor, as they generally show more guiding stars compared to the 6nm filter.

In areas with little light pollution, the background signal in images is usually limited by the sensor's dark current rather than light pollution. Therefore, further suppression of the sky background by reduction of the FWHM does not bring out more details in the object.

The 6nm Astronomik Narrowband-Emissionline filters are ideal for imaging faint objects in star-crowded regions of the milky way, as they typically halve the number of stars in the image compared to the 12nm filter. They are also suitable if you have a camera with very low dark current or if you are observing from a location with extreme light pollution.

Do I need to increase the exposure time?

Not necessarily, but you CAN! The high transmission rates ensure that almost all the light with the wavelength of the emission line reaches the sensor. For example, the intensity of the H-alpha light does not change significantly whether an Astronomik H-alpha filter is installed or not. But with an Astronomik H-alpha filter, all the unwanted light of other wavelengths that we do not want to record will be blocked.

The key benefit is not a requirement for longer exposures but rather the ability to do so if desired:

• Without a filter, the sky background in a light-polluted observing site might saturate the sensor within 30 seconds.

• With an Astronomik Narrowband-Emissionline filter, unwanted light pollution is effectively blocked, allowing for much longer exposure times - up to 30 minutes - without overexposing the background. This enables you to capture fainter details while maintaining a dark background for high-contrast images.

Imaging with Astronomik Narrowband-Emissionline filters

Imaging with Astronomik Narrowband-Emissionline filters is the best way to capture great images from light-polluted sites as they effectively block all kinds of light pollution. An Astronomik H-alpha filter is usually the first step in this field of astrophotography, allowing you to take deep and contrasty images even under heavy light pollution or a full moon. Astronomik H-alpha filters are ideal for imaging all red-glowing nebulae. Astronomik OIII filters expand your imaging possibilities by capturing greenish and blueish structures, making planetary nebulae, star-forming regions and supernova remnants great targets. Completing your filter set with an Astronomik SII filter enables you to create false-color emission line images similar to those produced by the Hubble Space Telescope using the HSO (H-alpha, SII, OIII) palette. 

Quality features of the Astronomik Narrowband-Emissionline filters

• High-quality substrate & advanced coating: Astronomik uses finely polished optical glass, free of any striae, residual stresses, and bubbles. Up to 170 interference coating layers are applied to both sides of the glass, serving as the actual filter itself and providing an anti-reflection coating.

• Exceptional durability & 10-year warranty: Thanks to Astronomik’s extraordinarily durable coating, all Astronomik filters are extremely scratch and moisture resistant and will not degrade over time. This is why we offer a 10-year warranty on all our filters.

• Integrated blocking: Astronomik Narrowband-Emissionline filters feature built-in ultraviolett (UV) and infrared (IR) blocking up to 1200nm, preventing unwanted UV and IR light from affecting images. You will not need an additional UV-IR block filter when imaging with any of our Narrowband-Emissionline filters.

• Parfocality: Thanks to extremely tight thickness tolerances, all Astronomik filters are parfocal, which means that there is no need to refocus when switching between filters.

• Neglectable wedge errors: Due to the high-precision machining of the carrier substrate, the wedge errors of Astronomik filters are far below all common tolerances.

• Optical quality: Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore effectively eliminated. 

• Wide range of sizes: Astronomik Narrowband-Emissionline filters are available in a variety of sizes and formats, from 1.25" up to 50x50mm² (square) filters, and also as Clip-Filter for various camera types.

• Premium storage: Each filter is delivered in a high-quality, long-lasting filter box.

All Astronomik filters are ideal for modern cameras, including both CMOS- and CCD-based models, ensuring you capture the best possible images with your equipment. Sharpness, contrast, and the absence of any reflections and halos are guaranteed. Even with bright stars in the field of view, nebulae and galaxies will be captured with the finest structures. 

Every Astronomik filter undergoes a rigorous quality control process before delivery. Additionally, each Astronomik Narrowband-Emissionline filter is measured using a high-end PerkinElmer Spectrophotometer to ensure it meets the specifications published on our website. On the back of each Narrowband-Emissionline filter box, you will find a label detailing the precise spectral data for that specific filter, including the maximum transmission and the recommended range of focal ratios.

The Astronomik Narrowband-Emissionline filters provide you with the highest quality raw data: the optimal starting point for further processing into a stunning astrophoto!

Detailed insights into each filter’s specific applications can be found on the individual product pages.