Space to Grow
Software - Astrometrica
How to read information in the FITS header
Your images from the Faulkes Telescope contain two parts -- the actual image data and a header which contains all the information about the image and how it was taken. This is similar to the EXIF data that is contained within pictures taken with ordinary digital cameras.
To view the header info for a Faulkes Telescope image, load the image in Astrometrica and then select Images » Display Header...
This will return the header information which looks similar to the example given below. The information you would probably be most interested in appears in red. In particular, you might want to:
- check which filter was used to take the image (FILTER 1, FILTER2)
- check the date your image was taken (DATE). Remember this date is given in Universal Time.
- check the start and stop times of your image (UTSTART, UTSTOP). Remember these times are given in Universal Time.
- check the exposure time of your image (EXPTIME)
- check the coordinates of the centre of your image (RA, DEC)
- check the coordinate epoch used (EQUINOX)
- check the name of the object/field (OBJECT)
The rest of the fields primarily give information about how the telescope and instrument is set up as well as a little information on the observing conditions for the night.
SIMPLE = T / A valid FITS file BITPIX = 16 / Comment NAXIS = 2 / Number of axes NAXIS1 = 1024 / Comment NAXIS2 = 1024 / Comment BZERO = 6508.82382550216 / Comment BSCALE = 0.239061188577751 / Comment ORIGIN = 'Las Cumbres Observatory Global Telescope Network' OBSTYPE = 'EXPOSE ' / What type of observation has been taken RUNNUM = 188 / Number of Multrun EXPNUM = 1 / Number of exposure within Multrun EXPTOTAL= 1 / Total number of exposure within Multrun DATE = '2007-04-12' / [UTC] The start date of the observation DATE-OBS= '2007-04-12T13:04:20.480' / [UTC] The start time of the observation UTSTART = '13:04:20.480' / [UTC] The start time of the observation UTSTOP = '13:05:21.599' / [UTC] The finish time of the observation MJD = 54202.544681 / [days] Modified Julian Days. EXPTIME = 60.0000000 / [Seconds] Exposure length. FILTER1 = 'clear ' / The first filter wheel filter type. FILTERI1= 'Clear-01' / The first filter wheel filter id. FILTER2 = 'Bessell-V' / The second filter wheel filter type. FILTERI2= 'Bessell-V-01' / The second filter wheel filter id. INSTRUME= 'HawkCam ' / Instrument used.
INSTATUS= 'Nominal ' / The instrument status.
CONFIGID= 14779 / Unique configuration ID.
CONFNAME= 'FAULKES_N_PCR-clusters-20070412-332662-CCD-Config' / The instrument c
DETECTOR= 'E2V CCD42-40'
PRESCAN = 0 / [pixels] Number of pixels in left bias strip.
POSTSCAN= 24 / [pixels] Number of pixels in right bias strip.
GAIN = 5.6000000 / [electrons/count] Pixel gain
READNOIS= 0.0000000 / [electrons/pixel] No value calibrated.
EPERDN = 0.0000000 / [electrons/count] No value calibrated.
CCDXIMSI= 2048 / [pixels] Imaging pixels
CCDYIMSI= 2048 / [pixels] Imaging pixels
CCDXBIN = 2 / Comment
CCDYBIN = 2 / Comment
CCDXPIXE= 0.0000000 / [m] Size of pixels, in X:UNKNOWN
CCDYPIXE= 0.0000000 / [m] Size of pixels, in Y:UNKNOWN
CCDSCALE= 0.2785000 / [arcsec/pixel] (Uncalibrated) Scale of CCD pixe
CCDRDOUT= 'DEFAULT ' / Readout circuit used.
CCDSTEMP= 258 / [Kelvin] Required temperature.
CCDATEMP= 258 / [Kelvin] Actual temperature.
CCDWMODE= F / Using windows if TRUE, full image if FALSE
CCDWXOFF= 0 / [pixels] Offset of window in X, from the top co
CCDWYOFF= 0 / [pixels] Offset of window in Y, from the top co
CCDWXSIZ= 2048 / [pixels] Size of window in X.
CCDWYSIZ= 2048 / [pixels] Size of window in Y.
CALBEFOR= F / Whether the calibrate before flag was set
CALAFTER= F / Whether the calibrate after flag was set
ROTCENTX= 544. / Comment
ROTCENTY= 443 / [pixels] The rotator centre on the CCD, Y pixel
TELESCOP= 'Faulkes Telescope North' / The Name of the Telescope
TELMODE = 'PLANETARIUM' / [{PLANETARIUM, ROBOTIC, MANUAL, ENGINEERING}] T
TAGID = 'UKRTOC ' / Telescope Allocation Committee ID
USERID = 'clusters' / User login ID
PROPID = 'NONAME ' / Proposal ID
GROUPID = 'NONAME ' / Group Id
OBSID = '812 ' / Observation Id
GRPTIMNG= 'FLEXIBLE' / Group timing constraint class
GRPUID = 1644 / Group unique ID
GRPMONP = 0.0000000 / [secs] Group monitor period
GRPNUMOB= 2 / Number of observations in group
GRPEDATE= '1970-01-01 T 00:00:00 UTC' / [date] Group expiry date
GRPNOMEX= 143.0000000 / [secs] Group nominal exec time
GRPLUNCO= 'BRIGHT ' / Maximum lunar brightness
GRPSEECO= 'POOR ' / Minimum seeing
COMPRESS= 'PLANETARIUM' / [{PLANETARIUM, PROFESSIONAL, AMATEUR}] Compress
LATITUDE= 20.7080000 / [degrees] Observatory Latitude
LONGITUD= -156.2570000 / [degrees West] Observatory Longitude
RA = '14:35:36.666' / World coordinate at the reference pixel
DEC = '-03:58:53.12' / World coordinate at the reference pixel
RADECSYS= 'FK5 ' / [FK4, FK5] Fundamental coordinate system
LST = ' 16:0:41.00' / [HH:MM:SS] Local sidereal time at start of curr
EQUINOX = 2000 / Date of the coordinate system
CAT-RA = ' 14:35:34.80' / [HH:MM:SS.sss] Catalog RA of the current observ
CAT-DEC = '-3:58:53.00' / [DD:MM:SS.sss] Catalog declination of the curre
CAT-EQUI= 2000.0000000 / [Year] Catalog date of the coordinate system fo
CAT-EPOC= 2000.0000000 / [Year] Catalog date of the epoch
CAT-NAME= 'EY-1:332662' / Catalog name of the current observation source
OBJECT = 'EY-1:332662' / Actual name of the current observation source
SRCTYPE = 'UNKNOWN ' / [{EXTRASOLAR, MAJORPLANET, MINORPLANET, COMET,]
PM-RA = 0.0000000 / [sec/year] Proper motion in RA of the current o
PM-DEC = 0.0000000 / [arcsec/year] Proper motion in declination of
PARALLAX= 0.0000000 / [arcsec] Parallax of the current observation so
RADVEL = 0.0000000 / [km/s] Radial velocity of the current observati
RATRACK = 0.0000000 / [arcsec/sec] Non-sidereal tracking in RA of the
DECTRACK= 0.0000000 / [arcsec/sec] Non-sidereal tracking in declinati
TELSTAT = 'OKAY ' / [---] Current telescope status
NETSTATE= 'ENABLED ' / Network control state
ENGSTATE= 'DISABLED' / Engineering override state
TCSSTATE= 'OKAY ' / TCS state
PWRESTRT= F / Power will be cycled imminently
PWSHUTDN= F / Power will be shutdown imminently
AZDMD = 222.1405000 / [degrees] Azimuth demand
AZIMUTH = 222.1405000 / [degrees] Azimuth axis position
AZSTAT = 'TRACKING' / Azimuth axis state
ALTDMD = 57.2449000 / [degrees] Altitude axis demand
ALTITUDE= 57.2449000 / [degrees] Altitude axis position
ALTSTAT = 'TRACKING' / Altitude axis state
AIRMASS = 1.1824530 / [n/a] Airmass
ROTDMD = 29.0700000 / Rotator axis demand
ROTMODE = 'SKY ' / [{SKY, MOUNT, VFLOAT, VERTICAL, FLOAT}] Cassegr
ROTSKYPA= -0.945209 / [degrees] sky position angle
ROTANGLE= 29.0693000 / [degrees] Rotator mount angle
ROTSTATE= 'TRACKING' / Rotator axis state
ENC1DMD = 'OPEN ' / Enc 1 demand
ENC1POS = 'OPEN ' / Enc 1 position
ENC1STAT= 'IN POSN ' / Enc 1 state
ENC2DMD = 'OPEN ' / Enc 2 demand
ENC2POS = 'OPEN ' / Enc 2 position
ENC2STAT= 'IN POSN ' / Enc 2 state
FOLDDMD = 'PORT 3 ' / Fold mirror demand
FOLDPOS = 'PORT 3 ' / Fold mirror position
FOLDSTAT= 'IN POSN ' / Fold mirror state
PMCDMD = 'OPEN ' / Primary mirror cover demand
PMCPOS = 'OPEN ' / Primary mirror cover position
PMCSTAT = 'IN POSN ' / Primary mirror cover state
FOCDMD = 36.6410000 / [mm] Focus demand
TELFOCUS= 36.6410000 / [mm] Focus position
DFOCUS = -1.4000000 / [mm] Focus offset
FOCSTAT = 'TRACKING' / Focus state
MIRSYSST= 'UNKNOWN ' / Primary mirror support state
WMSHUMID= 13.0000000 / [0.00% - 100.00%] Current percentage humidity
WMSTEMP = 279.8500000 / [Kelvin] Current (external) temperature
WMSPRES = 711.0000000 / [mbar] Current pressure
WINDSPEE= 1.1000000 / [m/s] Windspeed
WINDDIR = 85.0000000 / [degrees E of N] Wind direction
TEMPTUBE= 2.7900000 / [degrees C] Temperature of the telescope tube
WMSSTATE= 'OKAY ' / WMS system state
WMSRAIN = 'CLEAR ' / Rain alert
WMSMOIST= 0.0000000 / Moisture level
WMOILTMP= 8.7000000 / Oil temperature
WMSPMT = 0.0000000 / Primary mirror temperature
WMFOCTMP= 0.0000000 / Focus temperature
WMAGBTMP= 0.0000000 / AG Box temperature
WMSDEWPT= -20.0000000 / Dewpoint
REFPRES = 714.0000000 / [mbar] Pressure used in refraction calculation
REFTEMP = 281.1500000 / [Kelvin] Temperature used in refraction calcula
REFHUMID= 15.0000000 / [0.00% - 100.00%] Percentage humidity used in r
AUTOGUID= 'UNLOCKED' / [{LOCKED, UNLOCKED SUSPENDED}] Autoguider lock
AGSTATE = 'OKAY ' / Autoguider sw state
AGMODE = 'UNKNOWN ' / Autoguider mode
AGGMAG = 0.0000000 / [mag] Autoguider guide star mag
AGFWHM = 0.0000000 / [arcsec] Autoguider FWHM
AGMIRDMD= 0.0000000 / [mm] Autoguider mirror demand
AGMIRPOS= 0.0000000 / [mm] Autoguider mirror position
AGMIRST = 'IN POSN ' / Autoguider mirror state
AGFOCDMD= 10.1920000 / [mm] Autoguider focus demand
AGFOCUS = 10.1910000 / [mm] Autoguider focus position
AGFOCST = 'TRACKING' / Autoguider focus state
AGFILDMD= 'RETRACT ' / Autoguider filter demand
AGFILPOS= 'RETRACT ' / Autoguider filter position
AGFILST = 'IN POSN ' / Autoguider filter state
MOONSTAT= 'UP ' / [{UP, DOWN}] Moon position at start of current
MOONFRAC= 0.3044241 / [(0 - 1)] Lunar illuminated fraction
MOONDIST= 97.8946704 / [(degs)] Lunar Distance from Target
MOONALT = 2.9341603 / [(degs)] Lunar altitude
SCHEDSEE= 1.1942958 / [(arcsec)] Predicted seeing when group schedule
SCHEDPHT= 1.0000000 / [(0-1)] Predicted photom when group scheduled
ESTSEE = 1.4472946 / [(arcsec)] Estimated seeing at start of observa
L1MEDIAN= 47.35379 / [counts] median of frame background in counts
L1MEAN = 47.32362 / [counts] mean of frame background in counts
L1STATOV= 1 / Status flag for DP(RT) overscan correction
L1STATZE= -1 / Status flag for DP(RT) bias frame (zero) correc
L1STATZM= 1 / Status flag for DP(RT) bias frame subtraction m
L1STATDA= 1 / Status flag for DP(RT) dark frame correction
L1STATTR= 1 / Status flag for DP(RT) overscan trimming
L1STATFL= 1 / Status flag for DP(RT) flatfield correction
L1STATFR= -1 / Status flag for DP(RT) defringing correction
L1XPIX = 459.5198 / Coordinate of brightest object in frame after t
L1YPIX = 29.35189 / Coordinate of brightest object in frame after t
L1COUNTS= 789620.2 / [counts] Counts in brightest object (sky subtra
L1SKYBRT= 99.9 / [mag/arcsec^2] Estimated sky brightness
L1PHOTOM= -999. / [mag] Estimated extinction for standards images
L1SAT = F / [logical] TRUE if brightest object is saturated
BACKGRD = 47.35379 / [counts] frame background level in counts
STDDEV = 3.889794 / [counts] Standard deviation of Backgrd in count
L1SEEING= 6.654859 / [pixels] frame seeing in pixels
SEEING = 6.654859 / [pixels] frame seeing in pixels
PIXSCALE= 0.2785 / [arcsec/pixel] Nominal pixel scale on sky
CTYPE1 = 'RA---TAN' /
CTYPE2 = 'DEC--TAN' /
CRPIX1 = 544.0 /
CRPIX2 = 443.0 /
CRVAL1 = 218.902776939 / [degrees] World coordinate at the ref pix
CRVAL2 = -3.98142199 / [degrees] World coordinate at the ref pix
WRA = '14:35:34.8' / Original RA value from TCS before WCS fit
WDEC = '-3:58:53.0' / Original DEC value from TCS before WCS fit
WROTSKY = -0.0007 / Original sky PA value from TCS before WCS fit
EPOCH = 2000 /
CDELT1 = -0.000077260691 / [degrees/pixel]
CDELT2 = 0.000077260691 / [degrees/pixel]
CROTA1 = -0.945209 / [degrees]
CROTA2 = -0.945209 / [degrees]
CUNIT1 = 'deg ' /
CUNIT2 = 'deg ' /
CD1_1 = -0.000077250182 / WCS CD matrix
CD1_2 = 0.000001274516 / WCS CD matrix
CD2_1 = 0.000001274516 / WCS CD matrix
CD2_2 = 0.000077250182 / WCS CD matrix
SECPIX = 0.278138 / [arcsec/pixel] Fitted pixel scale on sky
IMWCS = 'WCSTools'
WCSRFCAT= '/data/Dprt/WCS/0218.895000-03.981388_usnob.starb' /
WCSIMCAT= '/data/Dprt/WCS/h_e_20070411_188_1_1_1_wcs.cat' /
WCSNREF = 18 / Stars in image available to define WCS
WCSMATCH= 12 / Stars in image matched against ref catalogue
WCREFCAT= 1 / 0 for failed, 1 for USNO-B, 2 for 2MASS PSC
LONPOLE = 180.0 / Native longitude of celestial pole
WCSRDRES= '0.1841/0.2329' / [arcsec] WCS fitting residuals, mean and sigma
WCSDELRA= 27.9 / [arcsec] Shift of fitted WCS w.r.t. nominal
WCSDELDE= -.1 / [arcsec] Shift of fitted WCS w.r.t. nominal
WCSDELRO= -.945 / [deg] Rotator shift w.r.t. nominal WCS
WCSDELPO= 27 / [arcsec] Shift of fitted WCS w.r.t. nominal
WCSSEP = 0.184 / [arcsec] Shift of fitted WCS w.r.t. nominal
WCS_ERR = 0 / Error status of WCS fit. 0 for no error
END
Return to the Astrometrica page
Exercitationem
Visi ut aliquid ex
Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur.
Visi ut aliquid ex
Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatu
Et harum quidem rerum facilis est et expedita distinctio.