Astronomik Filters H-alpha 12nm MaxFR XT Clip EOS R XL (85741)

The clip filters can be quickly and easily mounted inside the camera body without the need for any tools. You can insert or remove the filter at any time, even while on the go or at night. No modifications to the camera body are required. Removal is performed with a small hook, which is included in the package.

Compatible Models

These filters are compatible with Canon EOS R, EOS R3, EOS R5, EOS R6, EOS R6 MKII, EOS RP, EOS Ra, EOS R8, as well as APS-C models like R7, R10, R50, and R100.

Not Compatible With

The filters are not compatible with the following lenses: Canon RF 35mm f/1.8 IS MACRO, Canon RF 85mm f/1.2 L USM, Extender RF 2x, and Extender RF 1.4x.

Astronomik XT Filters for Wide-Angle Optics

These filters allow you to capture sharp, beautiful star images right to the edges of the frame, even with extremely wide-angle lenses. With other Astronomik filters, image quality in the corners may be reduced at short focal lengths. Even though these filters are made from just one millimetre of glass, this thickness can create aberrations with some wide-angle lenses, stretching stars into lines.

Astronomik XT filters use an ultra-thin carrier substrate that is only 0.3 millimetres thick. This significantly reduces "star streaks" in the corners. The substrate is finely polished, stress-free, and meets the highest demands of astrophotographers worldwide.

The ultra-thin glass still features Astronomik’s advanced coating technology, making the filters scratch-resistant, moisture-resistant, and non-ageing. The filters maintain their full performance even after many years of use.

MaxFR Filters

MaxFR filters are designed specifically for astrophotography with very fast telescopes, such as Celestron RASA optics or Omegon Pro Astrographs. For the most important lines—OIII, H-alpha, and SII—these filters are available with half-widths of 12 nm and 6 nm.

The filters provide optimal out-of-band blocking across the entire spectrum from UV to IR. This results in maximum contrast, minimal stray light, no halos, and the finest star images. With Astronomik MaxFR narrowband line filters, you obtain the highest-quality raw data, providing the best foundation for processing stunning astrophotographs.

Transmission and Use

• MaxFR filters with a 12 nm half-width can be used without restriction from f/1.7 to f/8, achieving about 85% of maximum transmission.

• MaxFR filters with a 6 nm half-width are usable from f/2.2 to f/8, achieving about 90% of maximum transmission.

The SII filter is optimized for high-contrast results by blocking H-alpha and NII (nitrogen).

Photography with Narrowband Line Filters

Under bright skies, line filters are the best way to begin astrophotography and achieve successful images. An H-alpha filter is usually the first recommended purchase. With this filter, you can take detailed photos even during a full moon or under bright sky conditions. It is the ideal filter for all nebulae that emit red light.

The OIII filter greatly expands your imaging possibilities, allowing you to capture greenish and bluish structures with high contrast and detail. Planetary nebulae and star-forming regions are particularly well-suited targets. The SII filter completes your HSO filter set, enabling color images similar to those taken by the Hubble Space Telescope.

Note that the H-beta filter is not available in the 6 nm version, as it has virtually no useful application.

Choosing the Right Half-Width

When shooting under dark skies, images taken with a DSLR or many cooled CCD cameras are limited by the camera’s dark current rather than the sky’s brightness. In such cases, a narrower half-width does not reveal more object detail. Compared to the 6 nm filters, the 12 nm filters generally make it easier to find guide stars with cameras that have built-in tracking sensors.

For cameras with very low dark current and efficient cooling, the 6 nm filters offer strong suppression of sky brightness, allowing longer exposures and deeper images. The narrower bandpass results in smaller stars, and faint stars may disappear almost completely. This is particularly useful in star-rich regions of the Milky Way, allowing faint objects to stand out clearly.

In summary, 12 nm filters are recommended for DSLRs and cameras with limited dark current. The 6 nm filters are ideal for highly light-polluted locations, for cameras with extremely low dark current, and when faint objects require maximum image contrast.

Specifications

• Central wavelength: 656 nm

• Half-value width: 12 nm

• Frame: Clip-Filters

• Transmission: 96%

• Mount material: Aluminium

• Coating: MRF

• Compatible with: Canon EOS

General Details

• Type: Filter

• Build type: Line filter

• Series: XT

• Useful for photography: Yes

• Visually useful: No

• Suitable for twin stars: No

• Suitable for moon and planets: No

• Suitable for nebulae and galaxies: Yes