AGO Teleskop

ecl> noao
      airvac        astutil.      ll            observatory   surfphot.
      artdata.      digiphot.     mtlocal.      obsutil.      twodspec.
      astcat.       focas.        nobsolete.    onedspec.     
      astrometry.   imred.        nproto.       rv.           

noao> digiphot
      apphot.   daophot.  photcal.  ptools.

digiphot> apphot
      aptest        findpars@     pconvert      polymark      psort
      center        fitpsf        pdump         polypars@     qphot
      centerpars@   fitsky        pexamine      polyphot      radprof
      daofind       fitskypars@   phot          prenumber     wphot
      datapars@     pcalc         photpars@     pselect       

Sledi nastavitev parametrov, najprej izračunam vrednost sigma neba, izmerim več slik, recimo sliko na začetku, na sredini in na koncu opazovaja:

apphot> imstat 0001V404Cyg-?.fts nclip=5
#               IMAGE      NPIX      MEAN    STDDEV       MIN       MAX
    0001V404Cyg-1.fts   1396130     4418.     67.64     4215.     4621.
    0001V404Cyg-2.fts   1393963     3981.     65.21     3785.     4177.
    0001V404Cyg-3.fts   1389557     3540.     61.49     3355.     3725.
apphot>

apphot> datapars
PACKAGE = apphot
   TASK = datapars

(scale  =                   1.) Image scale in units per pixel
(fwhmpsf=                  2.5) FWHM of the PSF in scale units
(emissio=                  yes) Features are positive ?
(sigma  =                  65.) Standard deviation of background in counts
(datamin=                 100.) Minimum good data value
(datamax=               57000.) Maximum good data value
(noise  =              poisson) Noise model
(ccdread=              RDNOISE) CCD readout noise image header keyword
(gain   =                 GAIN) CCD gain image header keyword
(readnoi=                   0.) CCD readout noise in electrons
(epadu  =                   1.) Gain in electrons per count
(exposur=             EXPOSURE) Exposure time image header keyword
(airmass=              AIRMASS) Airmass image header keyword
(filter =               FILTER) Filter image header keyword
(obstime=                   JD) Time of observation image header keyword
(itime  =                   1.) Exposure time
(xairmas=                INDEF) Airmass
(ifilter=                INDEF) Filter
(otime  =                INDEF) Time of observation
(mode   =                   ql)
($nargs =                    0)

Urejanje parametrov končam z tipko ctrl-D. Naslednja klučna nastavitev je velikost aperture. Če izbere premajhno, izgubim del svetlobe, če pa izberem preveliko potem zajamem v meritev še velik del neba, ki prinese tudi veliko šuma. Običajno izberemo za velikost nekoliko manjšo vrednost od FWHM.  Izmerim še

apphot> obsutil
      bitcount    cgiparse    kpno.       psfmeasure  specfocus   sptime
      ccdtime     findgain    pairmass    shutcor     specpars@   starfocus

obsutil> psfmeasure 0000V404Cyg-1.fts 
** Select stars to measure with 'm' and finish with 'q'.
** Additional options are '?', 'g', and :show.
NOAO/IRAF V2.16.1 bojan@lib Thu 12:34:01 21-Jan-2016

          Image  Column    Line     Mag    FWHM   Ellip      PA SAT
0000V404Cyg-1.f  458.39  720.15    1.42   2.272    0.22       0
                 537.41  743.85    0.34   2.184    0.23       2
                 553.85  562.39    0.00   2.280    0.18       1
                 691.24  548.64    1.77   2.250    0.37      -3
                 762.78  626.93    3.46   1.866    1.00      17
                 728.61  443.20    1.97   2.134    0.58       8

  Average full width at half maximum (FWHM) of 2.2304

Zdaj nastavim še aperturo in sicer na vrednost 1.4

apphot> photpars
PACKAGE = apphot
   TASK = photpars

(weighti=             constant) Photometric weighting scheme for wphot
(apertur=                  1.4) List of aperture radii in scale units
(zmag   =                  25.) Zero point of magnitude scale
(mkapert=                   no) Draw apertures on the display
(mode   =                   ql)
($nargs =                    0)