Baader H-Alpha 35NM Narrowband CCD Filter
H-Alpha 35nm CCD Filter 1.25" or 2"
Baader's new H-Alpha passfilter enables high-contrast deep sky images of H-II regions. Its medium 35nm FWHM bandwidth is ideal for interline CCD cameras. The lower sensitivity of interline transfer CCDs benefits from the more efficient 35nm FWHM. The sharp bandpass and > 90% high efficiency coatings make the Baader H-Alpha filter superior to the common colored-glass based filters, all at a reasonable price.
The Baader H-Alpha filter shares the same outstanding features as all the other Baader imaging filters. Unmatched optical quality, and high efficiency hardened multicoatings result in the sharpest and highest contrast images
Filter Durability: Filter durability has always been a hallmark of Baader Planetarium. The multi-layer dielectric coatings are plasma-assisted and Ionbeam-hardened using the latest technology (the coatings are harder than the glass substrate itself!). Baader filters withstand repeated real-world exposure to the elements and physical cleaning. Users need not leave their precious filters dull and dust encrusted to avoid cleaning - Baader filters may be used and cleaned without fear. We have heard sad stories from owners of other simpler soft-coated dielectric filters, who have seen their coatings degrade from normal exposure to moisture, or wiped away from routine cleaning. Some manufacturers even resort to sandwiching their delicate coatings in between two layers of glass (and risking blurred double images as well as eventual degradation from the edges inward). Baader Filters will truly last a lifetime.
Stackability: Unlike other filters, Baader Planetarium filters are truly designed to be stacked and combined. This is possible due to the high optical quality and highly efficient anti-reflection multicoatings. The ability to combine filters opens up many exciting possibilities, permitting unique spectral characteristics unachievable with any single filter.
Special Filter Cell: Baader's special filter cell design offers unique features that enhance their reliability and usability. Though difficult to produce, the ultra-thin filter cell results in the maximum possible clear aperture, in order to minimize vignetting (1.25" Filter clear aperture is 27mm, 2" Filter aperture is 45mm). The special threading has been designed to fit a wide variety of eyepieces and accessories (there is significant variation between the 1.25" filter threading used by eyepiece and accessory manufacturers). The front 'crown' of the filter incorporates milled notches which make handling and threading the filter a more secure operation in the dark.
Low cost: Despite high quality and advanced technology, Baader Planetarium filters are affordable.