The PMOD TSI composite shows peak-to-peak TSI variability of ~0.1% in each of the three solar cycles observed during the space-borne measurement record, with that variability being in phase with solar activity. The colors indicate the binary selections of different instruments used in the creation of the composite. The right-hand vertical scale indicates the more accurate currently-accepted absolute value. (“HF,” short for its creators Hickey and Friedan, is a name used by some authors for the NIMBUS7/ERB instrument in Fig. 1) (Figure is courtesy of the VIRGO team).