Andover Three Channel Nebula Filters
The Three Channel Nebula Filter works very well for both emission
and planetary nebulae. Unlike other nebula filters, this filter blocks
sky glow and passes emissions from the nebula, but also passes a
selected band of blue light which enhances the star clusters found in
the nebula. The filter also passes the Hydrogen Alpha line which is
important for photographing emission nebulae. These three pass
bands are unique to the Andover Three Channel Nebula Filter.
These premium multilayer dielectric filters are made in the USA
by Andover Corporation, an ISO-9001 supplier of filters to the
scientific, military and space industries. Each filter comes with a
spectrograph of that individual filter, not just 'stock' curves or
a few specs written on the package. Filter case included.
Check out this Review
by Ed Ting.
Specifications:
Optical Quality: TWF of 3-5l per 25mm and parallel to 1 minute of arc or better
Surface Quality: 80/50 or better per MIL-C-675
Bandbass: Greater than 92% at 495.9nm and 500.7nm, greater than 80% at 658nm
Coatings: Broadband anti-reflection coating on exterior surfaces
Durability: Per MIL-C-48497A, moderate abrasion
Construction: Laminated type filter mounted in a threaded ring
Clear Aperture: 1.25" is 28.6mm diameter, 2" is 45mm diameter
Spectral Data: Each filter is supplied with a spectral bandpass curve
Price includes FREE shipping in the USA!
Ordering
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