The Astronomik H-alpha filter is ideal for imaging HII regions from both light-polluted and dark observation sites.

The Astronomik H-alpha filter significantly enhances the contrast between objects emitting light at 656nm (H-alpha line) and the sky background, allowing for long exposure times for deep and high-contrast images.

The filter blocks the emission lines of high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, the maxima of typical LED lights, most lines of natural airglow, as well as most of the distracting moonlight.

The Astronomik H-alpha filter effectively blocks all unwanted light from wavelengths other than 656nm, from ultraviolet (UV) to infrared (IR).

The Astronomik H-alpha filter MUST NOT BE USED for solar observation!

Difference between Astronomik 12nm, 6nm and 4nm filters

The choice between 12nm, 6nm and 4nm Full-Width-Half-Maximum (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 optimized for use with system cameras with CMOS sensors. They are also a good choice for CCD cameras with normal or high dark current. The 12nm filters are also the preferred choice for cameras with an integrated or dual guiding sensor, as they show more guiding stars compared to filters with 6nm or 4nm FWHM.

The 12nm filters are the most affordable way to get started with Narrowband-Emissionline filters. Usually, the background signal in images taken from suburban or dark-sky locations is limited by the sensor’s dark current rather than light pollution. Therefore, further suppression of the sky background by reducing the FWHM does not reveal more details of the object.

The Astronomik MFR coating

Both the Astronomik MFR and MaxFR coatings offer extremely high contrast, minimized stray light, no halos and needle-sharp stars. In addition, they provide the best possible blocking across the entire spectral range from UV to IR.

12nm MFR-coated filters can be used in all instruments with aperture ratios from f/3 to f/15 without visible performance loss.

Astronomik XT-Filters

The new Astronomik XT-Filters are specifically designed for astrophotography with wide-angle lenses, delivering sharp and crisp star images all the way to the edges of the image.

Since many years, Astronomik Clip-Filters are a popular and well known tool among astrophotographers worldwide. However, when using very short focal length lenses to take widefield images, standard Clip-Filters could introduce aberrations, stretching stars in the outermost corners of the image. To solve this issue, the new Astronomik XT-Filters are coated on an extremely thin substrate of only 0.3mm or 0,5mm thickness, significantly reducing these aberrations.

Despite the reduced thickness, the Astronomik XT-Filters maintain the highest optical quality: they are finely polished, free of any striae, residual stresses, and bubbles, and are suitable for the most advanced imaging applications.

The Astronomik XT-Filters are manufactured using the same durable coating technology as all Astronomik filters. They are extremely scratch-resistant, unaffected by high humidity, and do not degrade over time. This ensures they retain their performance for years. As with all our filters, we underline this promise with a 10-year warranty.

Please note that not all Astronomik filters are available as XT-versions due to the complexity of manufacturing these ultra-thin filters. Currently, filters are produced that are predestined for photography with wide-angle lenses.

Clip-Filters for Sony Alpha 7 and Alpha 9 cameras

Sony Alpha 7 and Alpha 9 cameras are an excellent choice for astrophotography. With Astronomik Clip-Filters, you can use our full range of filters with your camera to capture stunning images. Whether paired with a camera lens or a telescope, our Clip-Filters ensure maximum image quality and performance from your setup.

The Astronomik Clip-Filters offer a number of practical advantages that make them an ideal choice for astrophotographers:

• Installing and removing the Astronomik Clip-Filter is very quick and easy and requires no extra tools or modifications to the camera body. They can be changed at any time, even at night.
• All lens functions, such as focus, aperture, and image stabilization remain fully functional.
• The Astronomik Clip-Filters are held securely in place without stressing the high-quality glass.
• The Astronomik Clip-Filters are designed and optimized for use with both standard camera lenses and telescopes.

Through the Astronomik Clip-Filters, we were able to solve several common issues faced by astrophotographers:

• Large filters for large camera lenses are very expensive.
• Using a filter holder between the camera body and the lens prevents focusing to infinity.
• For very fast telescopes (low f-number) like the Vixen R200SS or the Takahashi “Epsilon” astrograph, a filter drawer or filter wheel can not be used because the distance to the corrector lenses would be changed.
• Long exposure times lead to dust settling on the camera’s sensor chip.

Due to the very tight Sony bayonet and the limited space inside the camera, the Astronomik Sony Alpha 7 Clip-Filters cause a minimal obstruction in the corners. But this can be easily corrected by flatfielding.

Additionally, all Astronomik Sony Alpha 7 Clip-Filters serve as an excellent dust shield, protecting the sensor during long exposures. If you only need a dust shield without filtering effects, the Astronomik MC-Clear Sony Alpha 7 Clip-Filter is the right choice.

NOTE: Please store the Clip-Filter in the supplied storage box and do not leave it in the camera permanently.

Use Astronomik filters for your Sony Alpha 7 or Alpha 9 camera and enjoy marvelous images with ultra-light equipment!

Compatible Sony Alpha cameras

Model	Compatibility
Sony Alpha 7
Sony Alpha 7 Mk II
Sony Alpha 7 Mk III
Sony Alpha 7 Mk IV
Sony Alpha 7 Mk V
Sony Alpha 7C
Sony Alpha 7C Mk II
Sony Alpha 7CR
Sony Alpha 7R
Sony Alpha 7R Mk II
Sony Alpha 7R Mk III
Sony Alpha 7R Mk IV
Sony Alpha 7R Mk V
Sony Alpha 7S
Sony Alpha 7S Mk II
Sony Alpha 7S Mk III
Sony Alpha 9
Sony Alpha 9 Mk II
Sony Alpha 9 Mk III
Sony Alpha 58
Sony Alpha 68
Sony Alpha 77 (all variants)
Sony Alpha 99 (all variants)
Sony Alpha 6000
Sony DSLR cameras with A-bayonet

Non-compatible lenses

Model	Compatibility
Sigma 14mm F1.4 DG DN Art
Sony FE 12-24mm f2.8 GM (SEL1224GM)

Technical Data

• Guaranteed transmission of more than 90% at the H-alpha line (656nm)
• Typical transmission of 96% at the H-alpha line
• Full-Width-Half Maximum (FWHM): 12nm
• Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)
• Finely polished optical glass, free of any striae, residual stresses, and bubbles
• Extremely scratch-resistant and durable coating
• Completely resistant against high humidity and aging effects
• Astronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)
• Parfocal with other Astronomik filters
• Diffraction-limited
• Optimized spectral windows
• Delivered in a high-quality, long-lasting filter box
• Made in Germany

Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Thanks to the high-precision machining of the glas substrate, all Astronomik filters are parfocal. The wedge errors are far below all common tolerances. Therefore, all issues concerning focal distances and the exact alignment of images from each color channel are effectively eliminated.

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. The Astronomik MFR and MaxFR coatings are designed for optimal performance across a wide range of focal ratios of the optics used.

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 for best performance of that specific filter.