# Photometry extinction correction magnitude

I am learning photometry and I am wondering is the uncorrected extinction instrumental magnitude always less than the corrected extinction instrumental magnitude when applying transformation coefficients?

For example suppose the uncorrected extinction instrumental magnitude is $$m^A_V = 10.00,$$ will the corrected extinction instrumental magnitude always be greater than $$10$$?

• @KornpobBhirombhakdi Comments are not for answers. Oct 27 '20 at 19:12
• I used to put short answer in 'answer' and that upset people because it was not long enough. I will leave a long version for others. Oct 27 '20 at 19:23

## 1 Answer

If an object has a measured brightness, then it's extinction-corrected brightness will always be higher. Hence the extinction-corrected magnitude will always be smaller than the uncorrected (observed) magnitude.