Mid exposure time

To calculate the mid exposure time:

The average time at witch an object is exposed (mid exposure time), is increasing with every line of the image. (form the west to the east) To calculate the mid exposure time: M=S*L - E/2 + T1 ;
M=mid exposure time, S=shiftime (read out rate, time to read out one line), L=line number, E=effective exposure time, T1= time at the start of the image. This formula is not valid for the ramping at the start (or end, if, after closing the shutter, the rest of the lines is read in) of the image . The shiftime is stored in the file info like: Note = Sekunden je Reihe 0.171, Version 1.8 of SCAN adds a 'Shiftime' item to the file info like: Shiftime = 0.171. WinScan can use fits file format and adds a SHIFTIME item to the file header. The effective exposure time(E) is calculated (not for the ramping) by: E=Lccd*S
Lccd= lines on the CCD in the current binning mode, S=shiftime. This formula is not valid for the ramping at the start of the image( For the ramping it is: E=L*S/2 ) The effective exposure time (E=Lccd*S) is stored in the file info at Exposure = 80.123 (Or in fits files in EXPTIME and EXPOSURE ) Using the effective exposure time and the shiftime, the number of lines of the CCD in the current binning can be calculated: Lccd=E/S
The mid exposure time can be also calculated by ViewScan pressing with the right mouse button on an object and choosing "Mid Exposure Time".
The time and date, in fits files:
DATE-OBS= '2002-12-29T22:47:42.54' / UTdate of integration
The Time and Date in UT the first line of the image file was read out form the active image area of the CCD.
If the file is sliced in ViewScan, the time and date are calculated new, so the time and date in the slices are always the time and date the first line of the slice was read out from the active image area of the CCD.