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13 November 2023 at 2:35 pm
#620143
![](https://britastro.org/wp-content/uploads/2024/05/mark-phillips_avatar-80x80.jpg)
Participant
Thanks Mark,
What does Calibrate Photometry and MZero actually do?
Kevin
ASTAP compares the flux levels of the stars in the image against a catalog of stars which allows you to measure the brightness of any objects (photometry) in the image easily. MZERO is the magnitude zeropoint of the image and this can be used by comphot to measure the brightness of a comet for example.