The Optolong UV/IR cut filter is designed to block ultraviolet and infrared wavelengths and to capture the luminance in monochrome cameras.
Also, this filter is needed to cut off unwanted wavelengths in colour cameras which are sensitive to these radiations. Using one shot colour cameras without this filter will cause unnatural colour balances.
In refractors, the Optolong IR/UV cut is highly recommended to reduce the chromatic aberration, even in apochromatic telescopes as they are not corrected outside the visible spectrum.
The interferential coating are deposited on the substrate using electron-beam gun evaporation with Ion-assisted deposition coating technology. This increases the filters durability and resistance to scratching, as well as stability on CWL (central wavelength) and no deviation affected by temperature changes. The planetary rotation system offers precision and homogeneity of coatings ensuring high transmission of pass-band and high optical density off-band.
WARNING: Optolong filters are not designed for sun observations. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTERS. You could become BLIND if you fail to observe the warning.
|Passing band||Visible spectrum
2.0 mm (for 1.25" and 2" filters) ; 1 mm (clip series)
1/4 λ (wavefront)
|Band-pass transmission||Almost 100% across the visible spectrum
||60/40 (in accordance with US military watch MIL-O-13830)|
||Schott monolithic optical substrate (non glued)|
|Available sizes||1.25", 2", 36mm|
Bought one of these after imaging the Rho ophiuci cloud complex.
I was getting large halos around Antares from ASI 294MC camera and was suggested to try using the optolong UV/IR filter to reduce the halos I was getting around such a bright star.
Instantly when imaging at the next session the halos were gone from my subs and the colours for the stars were dramatically improved.
Really an essential purchase for a one shot colour camera