Aperture photometry - prototype

[capetillo]

As a user, I would like to be able to have an aperture photometry feature so that I can get a light curve from a supernova

• Use astroimagej as reference model
• Define the light curve entrypoint
• Sort frames by DATE-OBS
• Build a stable comp-star candidate catalog from the second HDU
• Exclude unusable comp candidates based on proximity, edges, contamination, and flags
• Rank comp stars using variability, brightness similarity, and isolation
• Apply photometric uncertainty propagation like astroimagej
• Compute ensemble differential photometry and calibrated apparent magnitudes
• Write tests