Baader H-alpha 2" bandpass filter (20 nm)

Compared to the CMOS-optimized Baader (Ultra) Narrowband filters, the 20 nm H-alpha filter lets much more light through. This makes the stars in the image brighter, allowing easier focusing, and the filter can be used at all focal ratios: There is no need for pre-shift as with narrowband filters.

This filter is especially interesting for users of color cameras (which are less red-sensitive than monochrome cameras) who do not need extreme narrow-band filters and want to enrich their color images with H-alpha. At the same time, this filter is a valid alternative to a standard R filter of the RGB scheme. It blocks much more of the deteriorating light pollution and still passes all H-alpha for all focal ratios.


A notable difference to all H-alpha pass filters on the market is the fact that this filter includes a highly efficient UV/IR blocking, being completely blocked up to 1400 nm, to eliminate the blur ("thermal noise") caused by unfocused light in refracting optics.



The Baader H-alpha Bandpass filter (20 nm) has all the advantages of the new generation of CMOS-optimized Baader filters:

Higher contrast, adapted to the quantum efficiency and s/n ratio typical of CMOS.

Reflex-Blocker™ coatings, for the highest absence of halos, even in the most adverse conditions of auxiliary optics.

Filter thickness identical to existing standards, with maximum care for parfocality

All-around blackened edges, with filter entrance side indicator in the form of a black outer edge on the telescope side, to additionally eliminate any reflections due to light hitting the edge of a filter, making additional front masks unnecessary.

Each filter is individually coated, with the coating edge sealed (NOT cut out of a larger plate with coatings left exposed, read more)

Life-Coat™: increasingly harder coatings to allow for a coating that will not age for life, even in the harshest environment.



Baader 2" H-alpha bandpass filter with 2" filter thread (M48)


H-alpha filter with 20 nm FWHM (CWL 656.3 nm), therefore excellently suited for night visual - and photographic use with CCD and CMOS cameras on telescopes with all f-ratios. Attention: this filter alone is not suitable for direct observation of the sun!


With new highly effective UV/IR blocking coating from 300 nm to 1400 nm


Similar to the Super G filter of O III, the 20 nm H-alpha filter is an excellent high-contrast deep-sky H-alpha/red filter for RGB applications, optimized for all CCD and color CMOS chips. It enables high-contrast imaging of H-II regions (e.g., North American nebulae) even from light-polluted environments.


Front-Reflex-Blocker™ hard-coated and plano-optical polished - with sealed coating edges (Life-Coat™).


Features:


NET WEIGHT (KG): 0.012
TRANSMISSION RANGE: H-alpha
FILTER THICKNESS (WITHOUT CELL): 2 mm
HBW (HALF-BANDWIDTH): 20 nm
CWL (CENTER WAVE LENGTH): 656.3 nm
COATING: AR Reflex-Blocker™ hard-coated, dielectric coated, plano-optical polished
FILTER SIZE: 2 inch
FILTER USAGE: CMOS, CCD, H-alpha, IR-Cut
FILTER MOUNTING: Mounted (LPFC 6mm)
FILTER TYPE: Narrow Band
SINGLE OR SET? Single filter
FILTER SHAPE: round