Calcium Ca-K Filters
These Calcium Ca-K filter modules are designed to upgrade your astronomical telescope for solar observing in the Ca-K wavelength during the day. The filter modules are alternatively installed in star-diagonals or straight extension tubes for 50.8 mm (2") focusers. Just place the filter module in the focuser of your telescope - that's all. Observing the sun in Ca-K light can't be easier!