Clearglass filter 2 Inch with low profile filter cell (LPFC).
This very useful addition to the Baader filter range is intended for the luminance channel in astro imaging.
Using narrowband filters can often result in slightly dimmer images, which can be difficult to resolve to a focus.
You can now use this filter to focus perfectly with a bright image and since they are also parfocal, switch to a different narrow band filter without loosing the focus.
This filter has the same substrate thickess as the other Baader filters.
Clearglass filter 2 Inch features:
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 less durable filters, who have seen their coatings degrade from normal exposure to moisture, or wiped away from routine cleaning. Some manufacturers of astro filters resort to coating large sheets of bulk glass, then literally cutting or breaking their filters from the precoated sheets, ripping and tearing the coating's edges in the process - leaving the edges susceptible to moisture penetration and coating peel. This literal shortcut gives a manufacturer the ability to reduce stock and easily produce filters on demand or to readily produce odd sizes, but it comes at the expense of the customer by producing an inferior filter with greater risk of coating failure. Other filters are produced by 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 lifetimes. Though we don't recommend trying this yourself, Baader filters have passed rigorous military durability tests that subject the filters to boiling water for several hours, then comparing spectral traces before and after. The Baader filters pass this test with no coating degradation.
Freedom from Ghosts and Halos: Baader Planetarium's filters have always been halo and ghost free. Baader balances each dielectric coating stack to avoid the ghosts and annoying halos that plague other manufacturers filters.