BL Lac 1308+326, June 2022

ATels #15441, #15447, #15459, #15474

from 15474: Our preliminary photometry of 1308+326 subsequent to our compilation presented
in ATel #15441, using comparison star C (R = 13.28) of Smith et al (1985,
AJ, 90, 1184), are presented below. We report only our first and last observations
for each night. The average brightness is calculated from typically one
dozen two-minute images taken in a sequence lasting about half-an-hour.

2022-06-20.10 UT (JD 2,459,750.60) R = 14.45 ± 0.02

2022-06-20.24 UT (JD 2,459,750.74) R = 14.42 ± 0.03

2022-06-21.09 UT (JD 2,459,751.59) R = 14.17 ± 0.02

2022-06-21.26 UT (JD 2,459,751.76) R = 14.12 ± 0.02

2022-06-22.10 UT (JD 2,459,752.60) R = 14.10 ± 0.02

2022-06-22.27 UT (JD 2,459,752.77) R = 14.07 ± 0.04

2022-06-24.11 UT (JD 2,459,754.61) R = 13.52 ± 0.02

2022-06-25.10 UT (JD 2,459,755.60) R = 13.44 ± 0.02

2022-06-25.24 UT (JD 2,459,755.74) R = 13.40 ± 0.03

2022-06-26.10 UT (JD 2,459,756.60) R = 13.26 ± 0.02

2022-06-26.24 UT (JD 2,459,756.74) R = 13.28 ± 0.03

We are aware that other observers use R = 13.20 for comparison star C (in
which case our measurement on 2022 June 26.10 would correspond to R = 13.18).
We continue to report our measurements using the comparison star C magnitude
R = 13.28 to be on the same scale as our previously reported ATel observations.

Observations were obtained with the Colgate University Foggy Bottom Observatory
(Hamilton, NY USA) 0.4-m Ferson telescope equipped with an FLI PL1001 CCD
camera. Student research participation at Colgate University has been supported
by the NASA / New York Space Grant, the Justus '43 and Jayne Schlicting
Student Research Fund, and the Colgate University Division of Natural Science
and Mathematics.

We encourage multi-wavelength observations of these outbursts.

Possible approach:

1) download images from ATLAS server
2) run source extractor on them (talk w Stubbs about SE parameter choices)
3) make sure object isn't saturated
4) extract photometry of both BL Lac and comparison star
5) determine magnitude differences between BL Lac and comparison star for each image. Make tabulation in both c and o bands
6) prepare and submit atel report.

Finding chart for comparison star C, from Smith et al 1985: image is N up E left, about 30 arcmin on a side.

Here is JPEG from ATLAS, which is roughly N up E left:

Raw ATLAS FITS images are roughly N down E right:

ATLAS postage stamps are 400 x 400 pixels, 1.86 arcsec/pixel.

ATLAS light curve:

ZIP file of ATLAS images:

ATLAS_BL_Lac_images.zip

Reduction steps:

flat-fielding of images, bias subtraction, crosstalk correction, etc. (done)
astrometric solution to build WCS parameters into the image header (done)
perform photometry on stack of images, paying attention to two different passbands. This produces a catalog of attributes for each source in the image. Many subtleties surrounding doing photometry- PSF-fitting vs. aperture photometry, sky subtraction, extinction and transparency.
construct aggregated source catalog, per band, for entire time series. This is the 'association' step.
determine magnitude differences between reference star(s) and source of interest. This alleviates systematic errors due to PSF variation and clouds and the like. Makes it a differential measurement.
think about zeropoints and converting from ATLAS filter system to UBVRI system. Can use Smith et al paper to do a rough version of this, or look up PASP ATLAS paper.
Construct data table of magnitudes vs. time.

Reference papers:

Smith_1985AJ_90.1184S.pdf

1980ApJ___235__717M.pdf

ATLAS FITS header:

SIMPLE = T / file does conform to FITS standard
BITPIX = -32
NAXIS = 2 / number of data axes
NAXIS1 = 400
NAXIS2 = 400
XTENSION= 'IMAGE ' / IMAGE extension
PCOUNT = 0 / required keyword; must = 0
GCOUNT = 1 / required keyword; must = 1
TIMESYS = 'UTC' / Time System for DATExxxx
RADESYS = 'FK5' / Celestial coordinate system
BZERO = 0.0000000000000E+00
BSCALE = 1.0000000000000E+00
MJD-OBS = 59751.28881575 / [UTC MJD] start of exposure (DFM)
MJD-CAM = 59751.2888135764 / [UTC MJD] camera shutter open time
CTRLID = '00087501122A705C' / controller backplane ID
EXPTIME = 30.0000 / [sec] Exposure time
DARKWAIT= 0.6 / [sec] Time from shutter close to readout
DARKTIME= 0.6000 / [sec] Dark current time
PRESKIP1= 10 / [pix] Pixels skipped before read
PIXREAD1= 1350 / [pix] Pixels read for image
OVRSKIP1= 0 / [pix] Pixels skipped after read
OVRSCAN1= 0 / [pix] Pixels read for bias
PRESKIP2= 0 / [pix] Lines skipped before read
PIXREAD2= 5300 / [pix] Lines read for image
OVRSKIP2= 0 / [pix] Lines skipped after read
OVRSCAN2= 0 / [pix] Lines read for bias
CCDBIN1 = 1 / [] Horizontal binning factor
CCDBIN2 = 1 / [] Vertical binning factor
EADU = 2.05 / [e/ADU] nominal amplifier inverse gain
GAIN = 2.05 / [e/ADU] nominal amplifier inverse gain
ARCH_SEQ= 13814694 / [] Archon sequence number
ARCH_TBK= 24.5 / [C] Archon backplane temperature
ARCH_T1 = 23.187 / [C] Archon module 1 temperature
ARCH_T2 = 25.687 / [C] Archon module 2 temperature
ARCH_T3 = 29.812 / [C] Archon module 3 temperature
ARCH_T4 = 31.187 / [C] Archon module 4 temperature
ARCH_T5 = 26.312 / [C] Archon module 5 temperature
ARCH_T6 = 25.25 / [C] Archon module 6 temperature
ARCH_T7 = 25.625 / [C] Archon module 7 temperature
ARCH_T8 = 25.125 / [C] Archon module 8 temperature
ARCH_T9 = 26.5 / [C] Archon module 9 temperature
ARCH_T10= 25.625 / [C] Archon module 10 temperature
AC_RTD1 = 792.623 / [ohm] Acam RTD1 resistance
AC_RTD2 = 783.874 / [ohm] Acam RTD2 resistance
AC_RTD3 = 781.495 / [ohm] Acam RTD3 resistance
AC_RTD4 = 1025.489 / [ohm] Acam RTD4 resistance
AC_RTD5 = 1034.517 / [ohm] Acam RTD5 resistance
AC_RTD6 = 1038.913 / [ohm] Acam RTD6 resistance
AC_RTD7 = 1046.765 / [ohm] Acam RTD7 resistance
AC_RTD8 = 1054.273 / [ohm] Acam RTD8 resistance
AC_TEMP1= -52.63 / [C] Acam temperature 1
AC_TEMP2= -54.83 / [C] Acam temperature 2
AC_TEMP3= -55.43 / [C] Acam temperature 3
AC_TEMP4= 6.52 / [C] Acam temperature 4
AC_TEMP5= 8.84 / [C] Acam temperature 5
AC_TEMP6= 9.97 / [C] Acam temperature 6
AC_TEMP7= 11.98 / [C] Acam temperature 7
AC_TEMP8= 13.91 / [C] Acam temperature 8
AC_IONON= 1 / [] Ion pump enabled?
AC_IONI = 0.105 / [A] Ion pump current
AC_IONV = 3.835 / [V] Ion pump voltage
AC_TECON= 1 / [] Acam TEC enabled?
AC_TECI = 4.299 / [A] Acam TEC current
AC_TECV = 21.716 / [V] Acam TEC voltage
AC_PRESS= -1000000 / [utorr] Acam micropirani pressure
AC_HALL1= 1.735971 / [V] Hall1 voltage
AC_HALL2= 1.640451 / [V] Hall2 voltage
AC_HALL3= 1.793325 / [V] Hall3 voltage
DETZ0 = 16. / [um] detector posn wrt nom
DETDZDX = 571. / [um/m] detector x tilt
DETDZDY = 652. / [um/m] detector y tilt
DETTEM = -52.63 / [C] Acam CCD temperature
TEC_LCLD= -54.83 / [C] Acam left cold TEC temp
TEC_RCLD= -55.43 / [C] Acam right cold TEC temp
TEC_LHOT= 6.52 / [C] Acam left hot TEC temp
TEC_RHOT= 8.84 / [C] Acam right hot TEC temp
MINFLOOR= 9 / [ADU] very smallest value in image
MINVALUE= 148 / [ADU] smallest typical value in image
MAXVALUE= 37532 / [ADU] largest typical value in image
SUBXTALK= 1 / Was cross-talk subtracted from image?
RDNOISE = 6.174 / [ADU] average read noise
AVEVAR0 = 1.623 / [e/ADU] ave/var in row 0
AVEVAR1 = 2.019 / [e/ADU] ave/var in row 1
AVEVAR2 = 1.921 / [e/ADU] ave/var in row 2
AVEVAR3 = 1.77 / [e/ADU] ave/var in row 3
AVEVAR4 = 1.964 / [e/ADU] ave/var in row 4
AVEVAR5 = 1.84 / [e/ADU] ave/var in row 5
AVEVAR6 = 1.843 / [e/ADU] ave/var in row 6
AVEVAR7 = 1.639 / [e/ADU] ave/var in row 7
AUXBIN = 8 / binning factor for var,sky,gain,bin images
SKYADU = 301 / [ADU] median background value
SKYRMS = 14.238 / [ADU] RMS of background
BCKGND = 293 / [ADU] sky level (-3.00sig = 0.0013quant)
SATURATE= 39024 / [ADU] saturation
NSATPIX = 43 / number of saturated pixels
EXTNAME = 'image '
NEXTEND = 10 / img,mask,var,gain,bkg,bin,cbias,rbias
FLATFILE= '/atlas/cal/01a/59696/01a59696o.pflat.fz' / flat file
DARKFILE= '/atlas/cal/01a/01a.dark' / dark file
DARKSCAL= 0.000496596067093711 / Factor multiplying calibration dark
MASKFILE= '/atlas/cal/01a/01a.mask' / mask file
PIXSIZE = 9. / [um] pixel size
DETECTOR= 'STA1600LN' / detector type
DETID = 'STA1600LN-SN20526' / detector serial number
CONTROLR= 'Archon ' / controller type
CAMID = 'green+fuzzy+4x' / ATLAS camera ID
DATASEC = '[1:10560,1:10560]'
DETSEC = '[1:10560,1:10560]'
BIASSEC = '[1:0,1:0]'
DATE-OBS= '2022-06-21T06:55:53+0000' / Exposure start time (UTC)
MJD-INST= 59751.288808 / [UTC-MJD] Initiation of camera exposure
MJDCAMOF= 0.614000 / [sec] true shutter open minus acam MJD-CAM
MJDDFMOF= 0.281000 / [sec] true shutter open minus DFM0
DATE = '2022-06-20T20:55:53-1000' / Date this file was created
OBSNAME = '01a59751o0108o' / Observation ID
OBSID = '01a59751o0108o' / Observation ID
FILTER = 'o' / Filter name
FILTID = '' / Filter ID
OBJECT = 'SR196N32' / Object
SURVMODE= 'SR196N32' / Survey mode (often same as OBJECT)
RA-CMD = 196.3569 / [deg] Commanded RA
DEC-CMD = 32.4600 / [deg] Commanded Dec
MNTFLIP = 0 / [] Pier side for mount (0=E, 1=W)
AZ-CMD = 308.2341 / [deg] Commanded Az
ALT-CMD = 66.8588 / [deg] Commanded Alt
MJD-MNT = 59751.28880900 / [MJD-UTC] Mount time
RA-MNT = 196.3570 / [deg] Mount RA
DEC-MNT = 32.4600 / [deg] Mount Dec
LST-MNT = 217.8550 / [deg] Mount local sidereal time
AXRA = 37626919 / [] Mount RA axis count
AXDEC = 6032681 / [] Mount Dec axis count
DOMEAZ = 38.6250 / [deg] Dome azimuth
DOMEDROP= 'NA' / Dome dropout status
ENVMJD = 59751.2885 / [MJD UTC] Boltwood report time
ENVTSKY = -62.0167 / [C] Boltwood sky temperature
ENVTEM = 9.9000 / [C] Boltwood outside temperature
ENVWIN = 16.9800 / [kph] Boltwood wind speed
ENVWDIR = 188 / [deg] Wind direction
ENVHUM = 7.0000 / [%] Boltwood relative humidity
SITELONG= -155.5761 / [deg] Site longitude, E of Greenwich
SITELAT = 19.5361 / [deg] Site latitude
SITEELEV= 3429.3000 / [m] Site elevation
OTATEMP = 9.4000 / [C] Temperature inside OTA
OTAHUMID= 2.0000 / [%] Humidity inside OTA
DOMETEMP= 8.5000 / [C] Temperature inside dome
DOMEHUM = 7.0000 / [%] Humidity inside dome
CHILLTEM= 3.0000 / [C] Water chiller
FOCUSNOM= 0 / [um] DFM nominal focus
FOCUSZ0 = 0 / [um] DFM nominal detector piston (Z0)
FOCM_VER= 'M9' / Focus model version
FOCM_W = -0.2 / [px] min astig
FOCM_F1 = -0.015 / [px/um] astig slope wrt focus
FOCM_F0 = 7704 / [um] focus origin
FOCM_A1 = -0.0029 / [px/deg] astig slope wrt alt
FOCM_A0 = 50 / [deg] alt origin
FOCM_D1 = 0 / [px/deg] astig slope wrt dec
FOCM_D0 = 0 / [deg] dec origin
FOCM_T1 = -0.0010376 / [px/C] astig wrt temp
FOCM_T2 = 0.0029 / [px/C/C] astig slope wrt temp*temp
FILTNUM = 0 / [0-7] DFM filter number
IWCOUNT = 0 / [] DFM filter insert/withdraw position
FOCUS = 7731 / [um] DFM focus
MJD-DFM0= 59751.28881250 / [MJD-UTC] DFM shutter launch
MJD-DFM1= 59751.28881880 / [MJD-UTC] DFM shutter open
MJD-DFM2= 59751.28915980 / [MJD-UTC] DFM shutter retreat
MJD-DFM3= 59751.28916600 / [MJD-UTC] DFM shutter close
RP_EXIST= 'T' / metadata file has reduction params
RP_FNMOS= 1 / how many devices in mosaic
RP_FGNVA= 0.0 / orange glownut default amplitude
RP_FGNGA= 0.0 / orange volcano default amplitude
RP_SCID = 'green+fuzzy+4x' / Name of camera on 01a (210908)
RP_STMIN= 100.0 / [ADU] min for do/tphot trigger
RP_STBIA= -20.0 / [ADU] offset 35mm for read noise
RP_SAPRD= 15.0 / [pix] imstars tphot aprad
RP_SSIG = 3.0 / sigma for tphot trigger
RP_SCHIN= 1.0e+04 / max chi^2/N for tphot trigger
RP_STRAT= 4.00 / maj/min limit for trailed images
RP_STCHI= 100.0 / chi limit for trailed images
RP_SVPSF= 2 / dophot variable PSF order
RP_SBLUR= 0.00 / FWHM image blur for dophot
RP_SFWHM= 2.50 / FWHM guess for dphot
RP_SAPM0= -14.0 / min mag for (ap-fit)
RP_SAPM1= -10.0 / max mag for (ap-fit)
RP_SAP0 = -0.8 / min value for (ap-fit)
RP_SAP1 = 0.0 / max value for (ap-fit)
RP_SAPGX= 8 / fiterp resolution in x for (ap-fit)
RP_SAPGY= 8 / fiterp resolution in y for (ap-fit)
RP_SSATL= 1.100 / estimate of flux loss when sat
RP_ASCL = 1.860 / [arcsec/pix] nominal plate scale
RP_APARI= 'pos' / [pos|neg] parity wrt view of sky
RP_ARFRC= 0.666 / search rad as a frac of width or height
RP_ACX = 5280.0 / [pix] FOV center wrt device origin
RP_ACY = 5280.0 / [pix] FOV center wrt device origin
RP_ICDIR= '/atlas/data/RC2/m17' / ref catalog path
RP_IDOGS= 0 / do GS15 first before refcat?
RP_INCEL= 10 / number of coverfrac cells
RP_ICMIN= 20 / minimum occupancy for coverfrac cell
RP_IRMAX= 1.0 / maximum acceptable restol
RP_ICMAX= 0.05 / maximum acceptable coverfrac
RP_IMLIM= 18.0 / [AB] limiting mag for ref search
RP_IMPH2= 1 / yes, retry imphot anet failures
RP_ICMX2= 0.450 / max acceptable coverfrac for fallback case
RP_IMCOL= 4 / orange refcat mag col (gri=345)
RP_ICCOL= 4 / refcat: color=CCOL-(CCOL+1)
RP_IXCLR= -0.555 / color term: AB=MCOL+X*color
RP_IABOF= 0.000 / offset from AB mags: m=ABoff+MCOL+X*color
RP_IDIST= 5 / distortion polynomial order
RP_ICUBE= -38.7 / [deg] angle where cubic term = 1
RP_IROT = 0.000 / [deg] nominal PA (+/-180) of image
RP_PAPRD= 0 / 0 or fixed aperture radius
RP_PBLOA= 0 / Bloat the PSF noise footprint?
RP_PBLUR= 0.0 / Blur by FWHM before running dophot
RP_PFWHM= 0 / Externally provided FWHM
RP_PVPSF= 2 / polynomial order for dophot variable PSF
RP_PNMAX= 3000000 / Max number of stars allowed (array size)
RP_PNMIN= 10000000 / Quit if this minimum number has been found
RP_PAPM0= -14.0 / min mag for (ap-fit)
RP_PAPM1= -10.0 / max mag for (ap-fit)
RP_PAP0 = -0.8 / min value for (ap-fit)
RP_PAP1 = 0.0 / max value for (ap-fit)
RP_PAPGX= 8 / fiterp resolution in x for (ap-fit)
RP_PAPGY= 8 / fiterp resolution in y for (ap-fit)
PSFMR1 = 2.040 / [pix] linear PSF radius: FWHM~1.5r1
PSFMR2 = 2.491 / [pix] quadratic PSF radius
PSFMQP = -0.081 / [pix^2] plus quadrupole
PSFMQC = -0.302 / [pix^2] cross quadrupole
PSFMQX = -0.127 / [pix^2] PSF x offset
PSFMQY = 0.192 / [pix^2] PSF y offset
PSFMQ3C = 0.128 / [pix^2] PSF phi=0 trefoil
PSFMQ3S = 0.010 / [pix^2] PSF phi=60 trefoil
PSFMBIN = 2 / PSF search bin factor
PSFMFWHM= 2.596 / [pix] PSF estimated FWHM
NSTAR = 30677 / Number of stars in tphot
FWHM = 2.6133 / [pix] PSF FWHM
PSFELONG= 0.6189 / PSF elongation = sqrt((a^2-b^2)/ab)
PSFQPLUS= -0.1104 / [pix^2] PSF plus quadrupole
PSFQCROS= -0.9948 / [pix^2] PSF cross quadrupole
PSFFLONG= 0.0042 / Fraction elongated more than 4.0
PSFPARNG= 0.98 / [deg] quartile range of elongated obj
PSFDBL = 0.01936 / [] fraction of split stars
PSFFW80 = 2.90 / [pix] 80th percentile FWHM
FWHM0 = 2.6722 / [pix] FWHM constant
FWHMX = 0.0562 / [pix/hCCD] FWHM x slope
FWHMY = -0.0089 / [pix/hCCD] FWHM y slope
FWHMX2 = 0.2452 / [pix/hCCD^2] FWHM x curv
FWHMXY = 0.0793 / [pix/hCCD^2] FWHM xy curv
FWHMY2 = 0.0116 / [pix/hCCD^2] FWHM y curv
FWHMRMS = 0.0147 / [pix] FWHM parabola RMS resid
ANETIME = 1.78 / [sec] anet compute time
ANETALG = 1 / anet sort algorithm
RA = 196.36377 / [deg] Field center RA (imphot)
DEC = 32.45870 / [deg] Field center Dec (imphot)
ZPRMS = 0.014 / [ABmag] scatter in mag zeropoint
ZPNPT = 7257 / Nstar in mag zeropoint
CDANAM = 0.000e+00 / CD anamorphic distortion
CDSKEW = 0.000e+00 / CD skewness
RARMS = 0.112 / ["] RMS scatter in RA dir
DECRMS = 0.097 / ["] RMS scatter in Dec
ZPDX = 0.007 / [mag/CCD] ZP tilt in x
ZPDY = 0.007 / [mag/CCD] ZP tilt in y
DZP = 0.010 / [mag] ZP RMS about tilted plane
ASTBLANK= 0.000 / Fraction of area lacking astro stars
ASTRESID= 0.110 / Astro resid relative to match tolerance
ANETFAIL= 0 / Did anet fail completely?
ANETDIST= 1 / Was anet distortion OK?
ANETCD = 1 / Was anet CD OK?
CLOUDIV = 1 / was cloud divided?
WCSAXES = 2 / no comment
CTYPE1 = 'RA---TPV' / TAN (gnomonic) projection + PV distortions
CTYPE2 = 'DEC--TPV' / TAN (gnomonic) projection + PV distortions
EQUINOX = 2000.0 / [yr] Time origin of coordinate system
LONPOLE = 180.0 / no comment
LATPOLE = 0.0 / no comment
CRVAL1 = 196.36377 / [deg] RA of reference pixel
CRVAL2 = 32.45870 / [deg] Dec of reference pixel
CRPIX1 = -1.85600000E+03
CRPIX2 = 4.60000000E+01
CUNIT1 = 'deg' / X pixel scale units
CUNIT2 = 'deg' / Y pixel scale units
CD1_1 = 5.170445379833E-04 / [deg/pix] Transformation matrix
CD1_2 = -1.291306744790E-05 / [deg/pix] Transformation matrix
CD2_1 = -1.295385996411E-05 / [deg/pix] Transformation matrix
CD2_2 = -5.170547417821E-04 / [deg/pix] Transformation matrix
IMAGEW = 10560 / Image width, in pixels.
IMAGEH = 10560 / Image height, in pixels.
SECPIX = 1.862 / [arcsec/pix] plate scale
PA = -178.569 / [deg] image position angle
PARITY = -1 / image parity with respect to RA/Dec
RADECSYS= 'ICRS' / Astrometric system
A_ORDER = 5 / Polynomial order, axis 1
B_ORDER = 5 / Polynomial order, axis 2
A_2_0 = -7.001123038285E-09 / RA distortion term
A_1_1 = 1.178854122546E-08 / RA distortion term
A_0_2 = -1.663138066640E-09 / RA distortion term
A_3_0 = -1.726086411758E-10 / RA distortion term
A_2_1 = 1.380568931422E-12 / RA distortion term
A_1_2 = -1.694636336308E-10 / RA distortion term
A_0_3 = 2.258357211551E-13 / RA distortion term
B_2_0 = 1.164553421891E-08 / Dec distortion term
B_1_1 = 7.941989254263E-10 / Dec distortion term
B_0_2 = 9.589590754900E-09 / Dec distortion term
B_3_0 = 3.971404531130E-13 / Dec distortion term
B_2_1 = -1.721277497452E-10 / Dec distortion term
B_1_2 = -2.849139307871E-13 / Dec distortion term
B_0_3 = -1.737676961634E-10 / Dec distortion term
PV1_0 = -1.392852188557E-13 / PV distortion term
PV1_1 = 9.999999999997E-01 / PV distortion term
PV1_2 = -5.151047667020E-09 / PV distortion term
PV1_4 = -1.465723887934E-05 / PV distortion term
PV1_5 = -2.219893826719E-05 / PV distortion term
PV1_6 = -3.116139393655E-06 / PV distortion term
PV1_7 = -6.454192797130E-04 / PV distortion term
PV1_8 = -4.613802817037E-06 / PV distortion term
PV1_9 = -6.332964244587E-04 / PV distortion term
PV1_10 = -1.248292617947E-06 / PV distortion term
PV2_0 = -1.640423856423E-14 / PV distortion term
PV2_2 = 5.151076871774E-09 / PV distortion term
PV2_1 = 9.999999999999E-01 / PV distortion term
PV2_6 = -2.211558509664E-05 / PV distortion term
PV2_5 = 2.286007059842E-06 / PV distortion term
PV2_4 = -1.850925349484E-05 / PV distortion term
PV2_10 = -1.434167227001E-06 / PV distortion term
PV2_9 = -6.431978810741E-04 / PV distortion term
PV2_8 = 2.449520807881E-07 / PV distortion term
PV2_7 = -6.495577723188E-04 / PV distortion term
MAGZPT = 22.196 / [ABmag] mag zeropoint: m=zp-2.5log(ADU/dt)
CLOUD = 1.016 / [] mean cloud transmission factor
CLOUDRMS= 0.043 / [mag] cloud transmission RMS
AP_ORDER= 5 / Polynomial order, axis 1
BP_ORDER= 5 / Polynomial order, axis 2
AP_1_0 = 5.253670082972E-06 / inv RA distort coeff
AP_0_1 = 6.590254916916E-08 / inv RA distort coeff
AP_2_0 = 7.011445956705E-09 / inv RA distort coeff
AP_1_1 = -1.154634436597E-08 / inv RA distort coeff
AP_0_2 = 1.615858705178E-09 / inv RA distort coeff
AP_3_0 = 1.718335652542E-10 / inv RA distort coeff
AP_2_1 = -1.415957014044E-12 / inv RA distort coeff
AP_1_2 = 1.683729662269E-10 / inv RA distort coeff
AP_0_3 = -2.333842574172E-13 / inv RA distort coeff
BP_1_0 = 3.874311407436E-08 / inv Dec distort coeff
BP_0_1 = 4.842225453050E-06 / inv Dec distort coeff
BP_2_0 = -1.163045093340E-08 / inv Dec distort coeff
BP_1_1 = -8.820608516843E-10 / inv Dec distort coeff
BP_0_2 = -9.375399979165E-09 / inv Dec distort coeff
BP_3_0 = -4.102685712762E-13 / inv Dec distort coeff
BP_2_1 = 1.710732135678E-10 / inv Dec distort coeff
BP_1_2 = 2.944856558752E-13 / inv Dec distort coeff
BP_0_3 = 1.730774611452E-10 / inv Dec distort coeff
A_4_0 = 4.363467401603E-17 / RA distortion term
A_3_1 = 2.034928816207E-16 / RA distortion term
A_2_2 = 1.227695068233E-17 / RA distortion term
A_1_3 = 1.508390252897E-16 / RA distortion term
A_0_4 = -4.187203583568E-17 / RA distortion term
A_5_0 = -2.437961509900E-19 / RA distortion term
A_4_1 = -3.003321218611E-20 / RA distortion term
A_3_2 = -6.047826248147E-19 / RA distortion term
A_2_3 = -9.652986084461E-21 / RA distortion term
A_1_4 = -3.133146370566E-19 / RA distortion term
A_0_5 = -4.921619936379E-21 / RA distortion term
B_4_0 = -1.231128210374E-16 / Dec distortion term
B_3_1 = -6.177240357130E-17 / Dec distortion term
B_2_2 = 1.670674884132E-16 / Dec distortion term
B_1_3 = -8.461747078144E-17 / Dec distortion term
B_0_4 = 1.791272787152E-16 / Dec distortion term
B_5_0 = -9.287437208955E-21 / Dec distortion term
B_4_1 = -2.783690343668E-19 / Dec distortion term
B_3_2 = 6.405974193735E-21 / Dec distortion term
B_2_3 = -6.066357194582E-19 / Dec distortion term
B_1_4 = 9.918106552294E-21 / Dec distortion term
B_0_5 = -1.770776924791E-19 / Dec distortion term
PV1_12 = 3.000296693967E-07 / PV distortion term
PV1_13 = -1.509686720796E-06 / PV distortion term
PV1_14 = 8.622246544046E-08 / PV distortion term
PV1_15 = -1.140873883816E-06 / PV distortion term
PV1_16 = -3.068052429029E-07 / PV distortion term
PV1_17 = -3.394607534176E-06 / PV distortion term
PV1_18 = 3.225539981077E-07 / PV distortion term
PV1_19 = -8.481628510020E-06 / PV distortion term
PV1_20 = 1.189075760771E-07 / PV distortion term
PV1_21 = -4.373567519113E-06 / PV distortion term
PV1_22 = 1.162680428919E-07 / PV distortion term
PV2_16 = 8.695633840132E-07 / PV distortion term
PV2_15 = -5.578554095628E-07 / PV distortion term
PV2_14 = -1.219562313434E-06 / PV distortion term
PV2_13 = -6.515637672889E-07 / PV distortion term
PV2_12 = -1.271212125040E-06 / PV distortion term
PV2_22 = 1.171476106515E-07 / PV distortion term
PV2_21 = -3.920251743206E-06 / PV distortion term
PV2_20 = -1.244808457260E-07 / PV distortion term
PV2_19 = -8.475103997983E-06 / PV distortion term
PV2_18 = 8.449466042560E-08 / PV distortion term
PV2_17 = -2.476069160822E-06 / PV distortion term
AP_4_0 = -3.921377510836E-17 / inv RA distort coeff
AP_3_1 = -2.348664574499E-16 / inv RA distort coeff
AP_2_2 = -5.197944700540E-18 / inv RA distort coeff
AP_1_3 = -1.764798225245E-16 / inv RA distort coeff
AP_0_4 = 4.560684457441E-17 / inv RA distort coeff
AP_5_0 = 3.659970349327E-19 / inv RA distort coeff
AP_4_1 = 3.092184342327E-20 / inv RA distort coeff
AP_3_2 = 8.641153867093E-19 / inv RA distort coeff
AP_2_3 = 9.943124690394E-21 / inv RA distort coeff
AP_1_4 = 4.460311350765E-19 / inv RA distort coeff
AP_0_5 = 5.029605281452E-21 / inv RA distort coeff
BP_4_0 = 1.199635530337E-16 / inv Dec distort coeff
BP_3_1 = 6.862842600957E-17 / inv Dec distort coeff
BP_2_2 = -2.020809835847E-16 / inv Dec distort coeff
BP_1_3 = 9.148444740066E-17 / inv Dec distort coeff
BP_0_4 = -2.021228566243E-16 / inv Dec distort coeff
BP_5_0 = 9.704774657795E-21 / inv Dec distort coeff
BP_4_1 = 4.113138332345E-19 / inv Dec distort coeff
BP_3_2 = -6.878710831603E-21 / inv Dec distort coeff
BP_2_3 = 8.656646045020E-19 / inv Dec distort coeff
BP_1_4 = -1.062406409798E-20 / inv Dec distort coeff
BP_0_5 = 2.954040902851E-19 / inv Dec distort coeff
OBSTYPE = 'object' / Observation type
AZ = 308.19627 / [deg] azimuth of field center
ALT = 66.83420 / [deg] altitude of field center
SECZ = 1.088 / [] airmass
AIRMASS = 1.088 / [] airmass
HA = 21.49422 / [deg] hour angle of field center
HA-HMS = '+01:25:58' / [h:m:s] local sidereal time
LST = 217.858 / [deg] local sidereal time
LST-HMS = '14:31:25' / [h:m:s] local sidereal time
LAMBDA = -179.673 / [deg] ecliptic longitude
BETA = 35.942 / [deg] ecliptic latitude
L2 = 94.082 / [deg] galactic longitude
B2 = 83.864 / [deg] galactic latitude
SUNELONG= 90.340 / [deg] angle to sun
MANGLE = 148.545 / [deg] angle to moon
MOONSKY = 21.000 / [mag] surface brightness from moon
SEEING = 4.866 / [arcsec] PSF FWHM
SKYMAG = 21.07 / [mag/sec^2] sky brightness
MAG5SIG = 19.51 / [mag] 5-sigma limiting magnitude
ENCNUM = 275 / Encoder samples
ENCDRA = 0.055 / [arcsec] RA encoder offset
ENCRRMS = 0.133 / [arcsec] RA encoder scatter
ENCDDEC = -0.013 / [arcsec] Dec encoder offset
ENCDRMS = 0.076 / [arcsec] Dec encoder scatter
CNPIX1 = 7.13600000E+03
CNPIX2 = 5.23400000E+03
END