Filter

Antlia CaK 3nm

Solar narrowband filter (Calcium K)

Passes the Ca II K line at 393.3nm

3nm FWHM bandpass

OD5 blocking 200-1200nm, OD3 1200-1500nm

Multi-coated

1.25-inch mounted (2-inch adapter available)

For high-resolution solar imaging of sunspots and granulation, not intended for visual use