synopsis: systematic uncertainty due to use of non-standard PHT-P aperture and non-proportionality of flux with aperture area.
limitations and applicability:
Per PHT-P filter the FCS was calibrated in a standard aperture. For this
the aperture scaling is not relevant. Non-standard apertures yield large
uncertainties.
description:
The normalized power on the detector (in W/mm) obtained from the FCS
calibration table has to be scaled with the size of the selected
aperture (in 
)
to obtain the actual FCS power.
purpose correction:
The actual power on the detector has to be scaled from the standard
aperture (normalized to 
)
to the selected aperture. In OLP7
it is assumed that the actual power is proportional to the physical area
of an aperture. Dedicated calibration observations have shown that this
assumption is wrong, especially for the biggest apertures (180'') for
the P1 and P2 detectors.
uncertainty/noise introduced:
Due to the incorrect assumption (power proportional to aperture area)
the photometric uncertainty is up to a factor 
5 for the largest
apertures w.r.t. the standard apertures.
auxillary data:
Areas of the apertures in