H Alpha 12 nm CCD Filter with T Threads
The Astronomik H-alpha filter is a
narrow band filter for CCD photography. The filter lets the H-alpha light of
emission nebulae pass and blocks nearly the whole remainder of the spectrum
where the CCD is sensitive.
The full width at half-maximum
(FWHM) of 12nm is optimized for the use with common CCD cameras and allows the
use of very fast optics. It should be noted that the filter has a transmission
of up to 99%.Another advantage of the 12nm filters is the availability of
guiding stars for cameras with a built-in-autoguider (SBIG). If you use a very
strong filter like our 6nm filter you often won’t find a usable guidestar.The
range of application extends from 1:2.8 to 1:15. Transmission losses and
chromatic distortions, which arise with other filters, only occur with
Astronomik filters when extremely bright aperture ratios of 1:2 and more come
The Astronomik H-alpha-CCD (12nm
version) increases the contrast between objects, in this case between the
H-alpha emission line and the skyglow background. Our Astronomik H-alpha-CCD
(12nm version) completely suppresses the emission lines of artificial lighting
(mercury (Hg) and sodium (Na)) and skyglow.
- When using the OIII CCD and the SII-CCD filters you can
obtain three-color images of emission line objects (gas nebulae) from
locations with very strong light pollution. To do so, you would take an
image in three different wavelengths, select each one as a color-channel
in Photoshop and paste them together as a color image.
- The Astronomik H-Alpha filters may NOT be used for
- If you plan to create color images from emission line
data, our CLS-CCD filter is a great choice for the Luminance channel.
Filed under: Eyepieces & Accessories