The H-alpha 6nm CCD Filter - SC Rear Cell by Astronomik:
This Astronomik H-alpha 6nm filter
is an extremely narrow emission line filter designed for astrophotography. It allows for the H-alpha light of emission nebulae to pass through while blocking almost the entire remainder of the spectrum where the CCD is sensitive. This filter's Full Width at Half-Maximum (FWHM) of 6nm was developed for superior contrast between H-alpha emitting targets and the background. Contrast increase is much greater than with Astronomik's 12nm emission line filters. However, you won't be able to view as many stars in the resulting images as with 12nm filters.The transmission curve design
makes this filter use with instruments from 1:3.75 to 1:15 achievable. All transmission curves of this 6nm filter are measured on their own. Thanks to this process, you get a filter that is optimized for your telescope.
The 6nm version of the Astronomik H-alpha CCD filter enhances the contrast between objects, in this instance between the H-alpha emission line and the skyglow background in the same fashion as the 12nm model. As a result of the smaller FWHM, the additional contrast is much higher. For observations from thickly light-polluted areas or of extremely faint objects, even in the Milky Way, the 6nm H-alpha filter is the correct choice. It thoroughly covers up emission lines of artificial lighting (mercury (Hg) and sodium (Na)) and skyglow. Unlike with competing filters, Astronomik filters will present problems with transmission losses and chromatic distortions only when extremely bright aperture ratios are brought into play.
By using this Astronomik 6nm H-alpha together with the 12nm H-alpha (sold separately), you get premium contrast in HII objects while keeping the stars in the final image. Do not use either of these filters for solar viewing.
If you intend to do false color imaging with other emission line filters, it would be advantageous to you to also get the matching filters with 12nm FWHM. Images captured with filters that have dissimilar FWHM are problematic when combining into the final image.
Astronomik H-alpha 6nm CCD Filter - SC Rear Cell Features:
- Parfocal with all other Astronomik filters
- 1mm glass thickness
- Entirely resistant to high humidity, scratches, and aging impact
- Diffraction limited, the filter will not lessen the optical performance of your telescope!
- Astronomik filters are presented in a high-quality, durable, filter box
OPT Product Number: AK-HA6-SCT