When using OpenWeatherMap for my environmental monitoring, I’m getting duplicate DEWPOINT headers. Both entries have different values. Based on my memory of this night’s imaging, the first value (-11) is the correct one. It looks like the second is just the ambient temperature again.
Here is a link to a file with the duplicates: Crab Nebula_0060_Light_1x1_Ha_0005_2018-03-03.fit - Google Drive
Headers from FITS Liberator:
Image #1
SIMPLE = T / file does conform to FITS standard
BITPIX = 16 / number of bits per data pixel
NAXIS = 2 / number of data axes
NAXIS1 = 4656 / length of data axis 1
NAXIS2 = 3520 / length of data axis 2
BZERO = 32768 / offset and data range to that of unsigned short
BSCALE = 1 / default scaling factor
CRPIX1 = 2328 / reference spectrum pixel coordinate for axis 1
CRPIX2 = 1760 / reference spectrum pixel coordinate for axis 2
CTYPE1 = ‘RA—TAN’ / standard system and projection
CTYPE2 = ‘DEC–TAN’ / standard system and projection
OBJECT = ‘Crab Nebula’ / Object name
DATE-LOC= ‘2018-03-03T21:58:34’ / Local observation date
DATE-OBS= ‘2018-03-04T02:58:34’ / UTC observation date
IMAGETYP= 'LIGHT ’ / Type of frame
CREATOR = ‘Sequence Generator Pro v3.0.0.7’ / Capture software
PROFILE = ‘CGX ASI1600-MM’ / SGPro profile name
INSTRUME= ‘ASI Camera (1)’ / Instrument name
OBSERVER= 'Rick ’ / Observer name
SITENAME= 'Monroe ’ / Observatory name
SITEELEV= 177 / Elevation of the imaging site in meters
SITELAT = ‘38d58m48.216s N’ / Latitude of the imaging site in degrees
SITELONG= ‘80d41m49.980s W’ / Longitude of the imaging site in degrees
FWHEEL = ‘ZWO FilterWheel (1)’ / Filter Wheel name
FILTER = 'Ha ’ / Filter name
EXPOSURE= 60 / Exposure time in seconds
CCD-TEMP= -10 / Camera cooler temperature
SET-TEMP= -10 / Camera cooler target temperature
XBINNING= 1 / Camera X Bin
CCDXBIN = 1 / Camera X Bin
YBINNING= 1 / Camera Y Bin
CCDYBIN = 1 / Camera Y Bin
XPIXSZ = 3.8 / Pixel Width in microns (with binning)
YPIXSZ = 3.8 / Pixel Height in microns (with binning)
TELESCOP= ‘Celestron Telescope Driver’ / Telescope name
RA = 359.775192026768 / Object Right Ascension in degrees
DEC = -0.0976934048215315 / Object Declination in degrees
CRVAL1 = 359.775192026768 / RA at image center in degrees
CRVAL2 = -0.0976934048215315 / DEC at image center in degrees
OBJCTRA = ‘23 59 06.046’ / Object Right Ascension in hms
OBJCTDEC= ‘+00 05 51.696’ / Object Declination in degrees
AIRMASS = 39.5855846644427 / Average airmass
OBJCTALT= 1.33506434043706 / Altitude of the object
CENTALT = 1.33506434043706 / Altitude of the object
FOCALLEN= 750 / The focal length of the telescope in mm
ANGLE = 0 / Image angle
SCALE = 1.045 / Image scale (arcsec / pixel)
PIXSCALE= 1.045 / Image scale (arcsec / pixel)
CLDCOVER= 1 / Cloud Cover in %
DEWPOINT= -11 / Dew Point in degrees C
HUMIDITY= 23 / Humidity in %
PRESSURE= 1010.5 / Pressure in hPa
RAINRATE= 0 / Rain Rate in mm/hr
TEMPERAT= 9 / Ambient Temperature in degrees C
WINDDIR = 350 / Wind Direction in degrees (0-359)
WINDSPD = 2.1 / Wind Speed in m/s
AMB-TEMP= 9 / Ambient temperature (in degrees C)
DEWPOINT= 9 / Dew point (in degrees C)
GAIN = 139 / Camera gain
EGAIN = 1.0011096841452 / Electrons Per ADU