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 Astronomik 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 into play.
Main use
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. Astronomik H-alpha-CCD (12nm version) completely suppresses the emission lines of artificial lighting (mercury (Hg) and sodium (Na)) and skyglow.
Other uses
- 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 solar observation.
- If you plan to create color images from emission line data, Astronomik CLS-CCD filter is a great choice for the Luminance channel.
It is not suitable for use in visual, nor for solar observation.
Transmission curve:
Technical Data
- typ. transmission of more than 95% at the H-alpha line (656nm)
- Complete blocking from all disturbing wavelengths in the infrared
- Parfocal with other Astronomik filters
- Glass thickness: 1mm
- Completely resistant against high humidity, scratches, and aging effects
- Diffraction limited, the filter will not reduce the optical performance of your telescope!
- Astronomik filters are delivered in a high-quality, long-lasting, filter box
- Since 2008 we do ship filters with a completely new design. Any kind of halo or strange reflection is a matter of past
Available in other sizes and formats. If you do not find the size you want, contact us at info@lunatico.es.
