Take your solar imaging to the next level with the Calcium Gen-II 1.25" Unstacked Ca-K Solar Imaging Filter with LPFC. This advanced filter allows you to explore the fascinating boundary region between the sun's photosphere, visible in white light, and the chromosphere, typically observed with narrow-band H-alpha filters. With the Calcium Gen-II filter, you can observe not only familiar white light structures like sunspots, but also the chromospheric network that covers the sun's entire surface. This network is a precursor to sunspot formation and is accompanied by supergranulation cells and Ellerman Bombs. The filter operates at the emission line of calcium at 394 nm, which is in the near UV spectrum. As such, it's crucial to remember that this filter is designed for camera use only, as the human eye is not equipped to safely handle UV radiation. For optimal results, we recommend using this filter with a monochrome camera and mirror telescopes. While many lens telescopes can still be used for calcium observations, unmodified DSLRs may require significantly longer exposure times. All calcium filters necessitate an additional solar filter. The Baader GEN-II package includes a sheet of AstroSolar Photo Film OD 3.8, 20x30 cm (#2459278) to construct your own solar filter, allowing you to start observing without the need for additional purchases. The Calcium Gen-II filter supersedes the older K-Line Filter 1 1/4" (stacked) # 2458355. Thanks