For special reasons I worked with very short exposure times using the latest SC (4.0.8861 pro 32bit under W10 64bit) and a QHY174GPS and an ASI1600. With both cameras and exposure times of 1 ms and below, the FITS headers DATE-AVG, DATE-END, DATE-OBS are all identical.
ASI1600 example:
Code: Select all
SIMPLE = T / C# FITS: 04/21/2022 21:25:00
BITPIX = 8
NAXIS = 2 / Dimensionality
NAXIS1 = 248
NAXIS2 = 14
GAIN = 400 /
TELESCOP= 'Telescope NN' /
OBSERVER= 'Observer NN' /
DATE-AVG= '2022-04-21T19:25:00.0004029' / System Clock:Est. Frame Mid Point
DATE-END= '2022-04-21T19:25:00.0004029' / System Clock:Est. Frame End
DATE-OBS= '2022-04-21T19:25:00.0004029' / System Clock:Est. Frame Start
SWCREATE= 'SharpCap v4.0.8861.0, 32 bit' /
FRAMETYP= 'Light ' /
XBINNING= 1 /
YBINNING= 1 /
BLKLEVEL= 30 /
YPIXSZ = 3.8 / microns
XPIXSZ = 3.8 / microns
EXPTIME = 0.0001 / seconds
ROWORDER= 'TOP-DOWN' /
BSCALE = 1 /
EXTEND = T / Extensions are permitted
CCD-TEMP= 28.8 / C
INSTRUME= 'ZWO ASI1600MM-Cool(49887988)' /
END Code: Select all
SIMPLE = T / C# FITS: 04/21/2022 22:51:59
BITPIX = 8
NAXIS = 2 / Dimensionality
NAXIS1 = 32
NAXIS2 = 32
GPS_W = 48 / Width
GPS_H = 43 / Height
GPS_LAT = 52.4338333333 / Latitude
GPS_LONG= 13.1966666667 / Longitude
GPS_SFLG= 51 / StartFlag
GPS_ST = '2022-04-21T20:51:59.0000000Z' / StartShutterTime
GPS_SU = 91676.4 / StartShutterMicroSeconds
GPS_EFLG= 51 / EndFlag
GPS_ET = '2022-04-21T20:51:59.0000000Z' / EndShutterTime
GPS_NT = '2022-04-21T20:51:59.0000000Z' / NowShutterTime
GPS_NFLG= 51 / NowFlag
GPS_TMP = 2 / TempSequenceNum
GPS_NU = 92094.1 / NowShutterMicroSeconds
GPS_PPSC= 10000328 / PPSCounter
GPSSTAT = 'Locked ' / GPS Status
GPS_EXPU= 417.700000000012 / Exposure (microseconds)
GPS_DSYS= 0.0024864 / System clock - GPS clock offset (s)
GPS_DSTB= 92 / Time offset stable for (s)
GPS_ALT = 0 / Altitude (m)
GPS_EU = 92094.1 / EndShutterMicroSeconds
GPS_SEQ = 277748 / Sequence Number
GAIN = 100 /
CAMID = 'ac38ca46858ef75a8' /
EXTEND = T / Extensions are permitted
BSCALE = 1 /
ROWORDER= 'TOP-DOWN' /
EXPTIME = 0.0004 / seconds
XPIXSZ = 5.86 / microns
YPIXSZ = 5.86 / microns
XBINNING= 1 /
YBINNING= 1 /
CCD-TEMP= 29.1 / C
FRAMETYP= 'Light ' /
SWCREATE= 'SharpCap v4.0.8861.0, 32 bit' /
DATE-OBS= '2022-04-21T20:51:59.0916764' / GPS:Start Exposure
DATE-END= '2022-04-21T20:51:59.0945805' / System Clock:Frame Received
DATE-OB2= '2022-04-21T20:51:59.0920941' / GPS:End Exposure
DATE-AVG= '2022-04-21T20:51:59.0916764' / GPS:Mid Exposure
OBSERVER= 'Observer NN' /
TELESCOP= 'Telescope NN' /
OBSLAT = 52.4338333333 /
OBSLONG = 13.1966666667 /
BLKLEVEL= 20 /
INSTRUME= 'QHY174M ' /
END Cheers, Christian
