The Astronomik H-alpha filter is perfect for imaging hydrogen nebulae whether there is light pollution or not. You’ll see a clear contrast between the background and an object glowing at 656nm. Once you see it, you’ll wonder how you did without one of these!
This Nikon XL Clip Filter is designed for the full-frame bodies from Nikon:
The filters sit securely and tension-free in the camera.Assembly and disassembly are easy with your finger, without tools!No changes to the camera are required to use the filters.
It fits: 
It doesn't fit: 
It looks like this: 
The clip filters are optimized for use with normal camera lenses and for use on a telescope.Because of the narrow bayonet and light well, the filters cause minimal additional shading for some optics, which unfortunately cannot be avoided.
Compatibility:
- The XL clip filters for Nikon have been tested with the models D750, D800, D810 and D850
- For the D850, you can only use manual focus lenses or a T-adapter (with a telescope). With AF lenses you will get an error message and the camera will not work.
(Workaround for this: With AF lenses on the D850 you can apply some tape over the lens contacts and the camera will work fine with the XL-Clip Filter installed.)
- Other bodies have not been tested yet.
- The Nikon XL-Clip will not work with cameras with APS-C sized sensors and not with the new mirrorless body. Clip-Filter for the APS-C sized models will be released in the near future.
This contrast boost is enabled by the high transmission of 96% of its 6nm narrow bandwidth, blocking all other unwanted bandwidths, and if you wanted a very dark background—this is how you get it.
The FWHM of 12 nm is optimized for typical DSLR cameras with CMOS sensors and CCD cameras with a normal/high dark current. With these cameras, the background signal in images taken from heavily light polluted sites is dominated by the dark current of the sensor. In this case, a further reduction of FWHM does not improve the image, as the background will not get darker. Compared to 6 nm filters this will yield more stars in the field of view which gives you more guiding stars when working with an integrated/dual guiding chip!
Thanks to the MFR coating technique, you may also use one single filter on all instruments up to f/3 without a significant reduction in performance.
DO NOT USE THIS FILTER FOR SOLAR OBSERVATION!
Technical data of the filter:
- Guaranteed transmission of more than 90% at the H-alpha Line (656 nm)
- Typical Transmission of 95% at the H-alpha Line (656 nm)
- Full-Width-Half-Maximum (FWHM): 12 nm
- Perfect blocking of unwanted light from UV up to the IR
- Parfocal with all Astronomik filters
- MFR Coating technique makes it usable with all optics up to f/3
- Thickness of 1mm
- Resistant to moisture, scratching, and aging
- An optically polished substrate, Striae-free, and free of residual stresses
- High-quality storage box
OPT University
United States