Ca II K 1-A Emission Index Composites

We describe here a procedure to combine measurements in the 393.37 nm Ca II K spectral line taken at different observatories. Measurements from the National Solar Observatory (NSO) Integrated Sunlight Spectrometer (ISS) on the Synoptic Optical Long-term Investigations of the Sun (SOLIS) telescope, the NSO/Sac Peak Ca II K-Line Monitoring Program, and Ca II K filtergrams from Kodaikanal Solar Observatory (KKL) are merged together to create a pair of composites of the Ca II K 1-A emission index. These composites are publicly available from the SOLIS website at http://solis.nso.edu/0/iss/.