The following program is carried out in order to consolidate the PHT 
calibration of chopped measurements and derive signal losses due to the high 
chopper frequency compared to signal stabilization time.

- observation of alpha Boo (Arcturus, HR 5340): background and star
staring plus chopped measurements.
This is a well known calibration star with a consolidated spectral
energy distribution. The star is sufficiently bright to be used as
a standard at wavelengths longward of 60 micron. Since the star is very
bright at the shorter wavelengths background observations are taken only
for filters longward of 60 micron.
 

Several filter are taken to have several contrast levels between background
and source.


.HISTORY
23/06/97        JA First version
 

.OTT 
.TDT