About this product
Model: baader_2961860
Part Number: 2961860
Baader C2 Swan-Band Filter (15nm) OIII Parallel
This Filter provides a contrast gain for comet hunters.
The Baader C2 SWAN-Band-Filter with ≤ 15 nm Half-Band-Width isolates the two C2 lines at 511 and 514nm.
These two emission lines, named Swan bands after their discoverer, dominate the spectrum of a comet's gas tail in the visible range. The filter allows only the light from the two carbon bands to pass through and, among other things, blocks the ubiquitous stray light, similar to a nebula filter in deep-sky observation. Structures in the gas tail thus become easier to observe, even under good observing conditions.
At the same time, this filter completely blocks the OIII line at 501nm and below, which other Swan-Band filters allow to pass. This provides even higher contrast, and comets with gas tails can be more easily distinguished from those dominated by a dust tail (where a SWAN filter offers only a small contrast enhancement).
For ambitious comet observers, a SWAN filter is an essential component of their basic equipment.
Just in time for introducing the new C2 Swan-Band filter, a bright comet, comet C/2022 E3 (ZTF), offered itself as a test object. Baaders customer, Andreas Bringmann, was one of the first testers.
This image was taken from a large city with an almost full moon. You can clearly see the amount of "doubly ionised carbon" (the carbon excited to glow radiates only in the wavelengths 511 nm and 514 nm) emitted by the comet. The filter shows the complete extension of the ion cloud around a comet:
C-2022E3_ZTF passes Hassaleh in Auriga (Baader C2 Swan-Band 15nm), imaged with Celestron EdgeHD 11", Takahashi FSQ-85ED | Moravian Instruments G3-16200 MK I, ZWO ASI6200MM Pro | 10Micron GM3000 HPS & Baader C2 Swand-Bad Filter, 2" (15nm), © A. Bringmann
Features
- Increased contrast, matched for typical CMOS quantum efficiency and s/n ratio
- Reflex-Blocker™ coatings, for the largest ever freedom from halos, even under most adverse conditions concerning aux-optics
- Identical filter thickness to existing standards, with utmost care for parfocality
- Blackened edges all around, with filter-lead-side-indicator in the form of a telescope-sided black outer rim, to additionally eliminate any reflection due to light falling onto the edge of a filter, making additional front masks obsolete
- Each filter is coated individually, with a sealed coating edge (NOT cut out of a larger plate with coatings left exposed )
- Life-Coat™ evermore hard coatings provide a non-ageing coating for life – even in the most adverse environment.
Customer reviews
| Average Rating (1 Review): | |
19 October 2023 | Owen
I got this filter in the 1.25 size just in time for the 2023 Kelling star party and tried it on several comets. I expected it failed to perform on the dusty ones but enhanced the view of 103P as this is as gaseous comet so it seemed to work well. The filter arrived well packaged as usual with Baader filters and FLO packaging. Well pleased. I need to compare it with my older Lumicon one and hopefully will have a chance to do that.
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