Astronomik 12nm H-Beta CCD Filter - 31mm Unmounted Round
The Astronomik H-beta filter is a narrow band emission-line filter for CCD photography. The filter lets the H-beta 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 better availability of guiding stars for cameras with a built-in-autoguider (SBIG). If you use a very strong filter like our H-alpha 6nm filter you often won’t find a usable guidestar. Together with the other three Astronomik emission-line filters you can do great color images even from very light polluted places! The filter has a built-in IR-blocker up to 1150nm. You don’t need an additional IR-blocker with this filter.
The Astronomik H-beta-CCD increases the contrast between objects, in this case between the H-beta emission line and the skyglow background. Our Astronomik H-beta-CCD completely suppresses the emission lines of artificial lighting (mercury (Hg) and sodium (Na)) and skyglow. The optimal aperture ratio for this filter is 1:3.5 to 1:6. 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.
When using the Astronomik H-beta CCD filter together with the H-alpha CCD, 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. Using the Astronomik H-beta filter together with the H-alpha-CCD you can create charts of the ionization energy in nebulae by creating an image from the ratio of H-alpha vs. H-beta. If you plan to create color images from emission line data, our CLS-CCD filter is a great choice for the Luminance channel.
The H-beta-CCD is also great for visual observation. If you plan to get filters for visual observation and for astrophotography get the CCD filter: You may use this filter visual as well as in front of you camera. The built-in IR-blocker doesn’t disturb visual observation but you need an additional IR-blocker if you want to use the visual filter with your camera.
Astronomik 12nm H-Beta CCD Filter - 31mm Unmounted Round Features...
- 98% transmission at 486nm (H-beta)
- Full width at half maximum 12nm
- Complete blocking from 350nm to 470nm and 500nm to 1100nm
- 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
The Astronomik Visual Hbeta filter #1 spectral transmission. Of course, an IR blocking filter is necessary for use this filter in conjunction with an infrared sensitive camera (CCD, moded DSLR, ...).
Detail of the Astronomik Hbeta filter #1 near Hbeta spectral line. The bleue dashed line indicate the position of Hb line (at 4861 A). The Cyan dashed lines indicate the position of the [OIII] doublet at 5007 A (the most intense component) and 4959 A.
The Astronomik Visual Hbeta filter #2 spectral transmission. From left to right the dashed lines indicates the position of Hb (bleue), [OIII] doublet (green), Ha at 6563 A (red) and [SII] line at 6730 A (cyan).
Detail of the Astronomik Photographic (or Visual) Hbeta filter transmission curve. The bleue dashed line indicate the position of Hb line (at 4861 A). The Cyan dashed lines indicate the position of the [OIII] doublet at 5007 A (the most intense) and 4959 A.
The same problem is encounter about the peak transmission of the bandwidth as the Astronomik Ha filter #2. The shift is more severe here ! Another proof...
Up image, part of the sun spectrum taken with the LISA spectrograph. Down image, same observation condition, only the Astronomik Hb filter #2 is added in the optical beam. The Hb line is nearly out of band of the filter.
The Astronomik Photographic (or visual) Hbeta filter #2 transmission for three incident angles. 0° tilt curve, the f/8 input beam is normal to the filter surfaces. 5° tilt curve, the filter is tilted by a angle of 5° relative to the f/8 input beam (simulate approximately the marginal rays of a f/5.6 telescope). 6.5° tilt curve, the filter is tilted by a angle of 6.5° relative to the f/8 input beam (simulate approximately the marginal rays of a f/4.3 telescope). The dashed line indicate the position of Hb.
|Name||Astronomik - 12nm H-Beta CCD Filter - 31mm Round Unmounted|
|Custom Stock Status||Available - Ships in 3-5 Days|