Filter cutting the infrared spectrum longer than 690 nm. In the visible area, the transmission reaches 95%.
They allow taking photos of emission nebulas in the h-? range (this line - ? = 656 nm - is passed through the filter). Permeates UV without changes.
The filter has a 2 "filter thread on both sides of the luminaire, thanks to which it can be combined with other filters in this standard.The filter surfaces meet strict quality tolerances, while dielectric coatings guarantee scratch resistance and durability filter characteristics over time.
CCD and CMOS matrices are sensitive in the UV and IR areas (ultraviolet and infrared), while lenses of telescope lenses are not usually well corrected outside the visible spectrum, therefore the contrast of images without an IR filter can be lowered. The filter is recommended for astrophotography.
• fixing: through a 2 "filter thread