Observing Parameters

• DARK: select or de-select dark signal measurement. Selection of a dark measurement is strongly recommended for fainter total flux where the dark contributes significantly to the total signal, e.g. measurements of the Zodical Light below 5 micron (see worked examples for more details of critical flux levels).
• COLD_FCS: select or de-select cold FCS measurement for straylight determination. The straylight contribution depends on the detector used for the observations. It amounts to several percent of the extended background level in the CFOV.
• FILTER: specify central wavelength of filter requested.
• APERTURE (for PHT05 only): specify aperture to be used.
• POINT OR EXTENDED SOURCE: specification of source type, this parameter defines whether the EXPECTED SOURCE FLUX is given in Jy or MJy/sr.
• EXPECTED SOURCE FLUX: best available estimate of source flux
• UNCERTAINTY IN SOURCE FLUX: uncertainty of source flux estimate, parameter is used to adjust the dynamic range.
• MAXIMUM BACKGROUND FLUX: expected background flux at source position. Parameter can be set to zero for absolute sky brightness measurements, if total flux is given by EXPECTED SOURCE FLUX.
• INTEGRATION TIME or S/N: the user specifies the integration time requested, or, alternatively, the required signal-to-noise ratio. Note that the FCS measurement has the same length as the sky measurement.