The Gaia satellite has images about one billion stars in Gaia-G, red and blue magnitudes. From the latest Gaia DR2 release it is possible to calculate the Johnson-V magnitude and use for photometry.
Below an comparison between the magnitudes in AASVO charts and measured magnitudes of an image taken with a ASI1600 camera (only an UV-IR block filter).
The magnitude values in the image are measured by ASTAP using the Gaia Johnson-V star database.. The program can do an astrometric (plate) solving and calibrate the measured star flux using a few hundred Gaia stars found in the image. Below two results:
Comparison AASVO chart vs a measured image for M5:
Comparison AASVO chart vs a measured image for M31:
Are the AAVSO reference stars still required after Gaia DR2? I noted that the AAVSO has added the reference "48 Gaia DR2" for some stars, but are the Gaia satellite measured values not more accurate then the old ground based observations?
-- Han