PSF-Photometry repository has public visibility

American Association of Variable Star Observers (AAVSO)
Sat, 02/03/2024 - 15:17

I am inviting anyone who is interested in photometry to check out my repository on GitHub:

It contains a program called MAOPhot (version 1.0.0) (MAOPhot name is like DAOPhot)

If you are interested in collaborating send me an e-mail and I will add you to the repository access list so you can make branches, etc. There are plenty of things that 
can be improved. (

Here is more info about MAOPhot 1.0.0:

This program was derived from MetroPSF by Maxym Usatov. It has been streamlined, updated, and made exclusively for AAVSO reports.

MAOPhot calculates stellar magnitudes from Fit (*.fit, *.fits, *.fts) formatted digital photographs using PSF photometry. It produces an extended AAVSO (American Association of Variable Star Observers) report which can be submitted to the AAVSO using their online tool WebObs (

MAOPhot uses the PSF (point spread function) Photometry method exclusively. 

PSF modeling is well suited for measuring stellar magnitudes in crowded fields, or the magnitude of a star that has a close companion, e.g., Z Tau. 

MAOPhot is written in Python using Astropy (a common core package for astronomy). MAOPhot also uses photutils.psf. See "PSF Photometry" ( which describes many of the classes and methods used in MAOPhot.

MAOPhot has been redesigned for AAVSO reporting only and includes, but not limited to the following enhancements:

o    uses Astropy 6.0.0 and photutils.psf 1.10.0 (all packages required have version specified in requirements.txt file)

o    generation of Effective PSF model (EPSF model), and ability to create a ‘rejection list’ of stars that the user can select that will not be part of the EPSF model 

o    option to use an Integrated Gaussian PRF (Pixel Response Function) as model

o    PSF Photometry using an iterative algorithm to perform point spread function photometry

o    PSF Photometry using a non-iterative algorithm to perform point spread function

o    PSF Photometry using an ensemble of comparison stars or a single comp star

o    generation of Two-Color Photometry (B, V), (V, R) or (V, I), and Single Image Photometry reports in AAVSO extended format 

o    use of telescope Transformation Coefficients (needed for Two Color Photometry)

o    user can specify check star and list of comp stars to use

o    a Radio Button option to display all AAVSO comp stars as AAVSO label numbers and any found VSX objects in image field or only VSX and AAVSO comp stars specified in settings 

o    intermediate results are saved as .csv files

o    user can optionally enter a AAVSO Chart ID when retrieving comparison star data

o    if intermediate results include found comp stars or VSX objects associated with an image being loaded, then these objects are displayed


See HelpFile.pdf in