FOS IDT Report RSDP/FOS-003
Conversion to Absolute Flux Units

D. Lindler, R. Bohuin


1987 September 3


The FOS RSDP conversion to absolute flux units are tested using the
input data (Figure 1) with an exposure time of 0.5 seconds. The
standard quarter stepped FOS spectrum with an overscan of 5 diodes is
used.


RSDP conversion to flux units, given in SE-06 is a point by point
multiplication of the count rate vector by an inverse sensitivity
vector of the same length. The inverse sensitivity vector is selected
for the given detector, dispenser, polarizer mode, and aperture.


Tbe following steps in the RSDP processing were performed in testing
the conversion to flux units.


1.	Conversiou to count rates

2.	Background subtraction (a default background of 100 counts/sec
  	was used for testing purposes. This background allowed testing
  	of the treatment of negative net flux values)


3.	Conversion to fiux units

4.	Error computation

The inverse sensitivity curve used for testing is shown in Figure 2
and has values typical of the FOS inverse sensitivity.


Results ofthe RSDP (Figure 3) were compa.red to the duplicate
processing done using FOS IDT software. Differences in the RSDP and
IDT results for both the flux and error vector were negligible (less
than 1 part in i0~) and can be attributed to computer round off
errors.


Conclusions:

1.	RSDP correctly multiplied one vector with another, or in other words;

2.	Conversion to flux units and error propagation through the
  	conversation 1s being properly performed by RSDP.