| Film based astrophotometry is not linear |
Please, click here to see the Orion image taken with film (Fuji NPH 400 ASA)
Please, click here to download the Excel file showing the studied stars
Using CurveExpert software: After entering
the x,y pairs of data (reference and measured stellar magnitudes),
CurveExpert finds the better fitting-curves, ranking them.
This is the curve obtained for Fuji 400
NPH. The horizontal axis shows the reference values, while the vertical
awis shows the measured values
After finding the fitting curve,
interpolating values is easy. Here we simulate a measured star of 10.5
magnitude, then, from the model, the "real" magnitude should be mv =
8.08