Using APASS and 2GSS for studying variable stars

The AAVSO Photometric All-Sky Survey (APASS) provides calibrated magnitudes in the range 7 < V < 17 for the entire sky, in the BVugriZsY bandpasses. While primarily designed for 0.02 mag calibration, it provides photometry over a many-year baseline, and also has near daily cadence in the standard field regions on the equator. Likewise, the Second Generation Synoptic Survey (2GSS) is a follow-on to APASS, and will provide daily cadence in two passbands for the entire sky.