The Baader C2 Swan-band filter isolates the two diatomic carbon lines at 511 & 514nm, which dominate the spectrum of a comet's gas tail and plume, respectively. Unlike other Swan-band filters on the market, this filter completely blocks the OIII line at 501nm and below.
The C2 filter has a central wavelength of 512nm with a half-width of ≤15nm. This makes it useful not only for cometary imaging, but as an OIII parallel filter to better remove stars from images, as well as a solar filter in a previously inaccessible part of the spectrum (only with the appropriate energy rejection filter!).
Available in either 1.25" or 2" mounted. The filter cell is threaded on both ends so that multiple filters can be stacked. All Baader filters (excluding 100 x 100mm) come in stackable labelled filter boxes which can be attached to each other to form a sturdy filter library.
WARNING: This filter alone cannot be used for direct solar observation!
Baader CMOS-Optimized filters - advantages
- Very high contrast due to steep edges of the coating
- Reflex-Blocker coatings to minimize reflections caused by correctors, reducers and other optical elements
- Standardized thickness for maximum possible parfocality - less need to refocus due to different filter thicknesses
- Blackened edges with front-side markings
- Each filter is individually fine-polished and coated with sealed coating edge, preventing moisture ingress
- Life-Coat for hardness and age-resistance, making the filters able to withstand tougher conditions for longer
For more information on Baader's new generation of CMOS-optimized filters, check out this blog post!
|≤505 - 520 nm
|513 nm (for the C2 lines at 511 and 514 nm)
|Type of filter
|Gas evolution of comets, O-III-parallel Imaging, Contrast Enhancement
Phantom Group coating, planeoptically polished
|2 mm (without cell), 6 mm with cell
|1.25" / 2" mounted
BA2961860 (1.25"), BA2961863 (2")