Astrophysical timing derived from photometric relative phase measurements of periodic stellar variability

A method for deriving a current astrophysical time comprising:

• creating, with a computer, a database of reference measurements, wherein each reference measurement corresponds to a separate celestial source having a periodically-varying brightness, and wherein each reference measurement includes data about the corresponding celestial source's photometric structure at a given time, at a given stellar period, and at a known periodic phase;
• creating a phase-folded light curve for each celestial source having a reference measurement in the database;
• at a first subsequent time, collecting photons from a plurality of the celestial sources having a reference measurement in the database to create a first target measurement for each of the plurality of celestial sources at the first subsequent time;
• comparing each first target measurement to a corresponding phase-folded light curve to derive a first set of possible phase differences, wherein each possible phase difference corresponds to a potential derived time based on the given time and the given stellar period of the corresponding reference measurement;
• and
• analyzing the first set of possible phase differences to derive the current astrophysical time.