Planetary filter Optolong U-Venus 2"
Primary Use
The U-Venus filters Optolong are specially designed to enhance the contrasts of the planet Venus and to observe cloud structures in both visual observation and astrophotography.
The filter can be used with monochrome CCD cameras without a UV-IR blocking filter and/or a protective clear filter. For use with digital SLR cameras the built-in low pass filter must be removed. This is possible because the sensor of CCD or CMOS cameras is capable of detecting light in the 350-1100 nm range when devoid of filters that limit the bandpass to visible light only.
Moreover, the Optolong U-Venus planetary filter acts as an excellent dust shield, preventing the possibility of dust settling on the lens during prolonged exposure.
Technical Features
- Schott substrate material
- Thickness: 2.0mm
- Surface quality: 60/40 (refer to MIL-O-13830)
- The filter is made from optical glass with a flatness level of λ / 4 on both surfaces (surface irregularities are
- 80% maximum transmission in the spectral region 320-370 nm
- Accurately blocks wavelengths outside the passband, i.e. wavelengths between 200-280 nm (ultraviolet) and spectral regions of the visible and infrared.
- The ultra-thin filter cell minimizes vignetting by allowing a diaphanous aperture of 45 mm for 2" (50.8 mm), having been manufactured in aluminum by CNC machines with extreme manufacturing precision.
Coating features
- Multi-coated anti-reflective coating
- Non-cementitious optical substrate coating
- Outermost coating with ion-assisted electron beam evaporation deposition technology provides increased durability and scratch resistance, as well as CWL (center wavelength) stability unaffected by temperature changes.
- The planetary rotation system provides precision and homogeneity of coatings, ensuring high through-band transmission value and high out-of-band optical density
Planetary filter Optolong U-Venus 2" Planetary Filter
