Scripts for Instrument Startup

MODS: adjust left and right rotator zeropoints (not yet on the obs computers)

  • obtain a series of star images with detxy +Y offset in between these and a slit image
  • run in LBTtools.Sandbox to analyze these images and output a recommended adjustment to the rotator zeropoint
    • Dependencies: 2 python scripts are called by, and These are in the subdirectory of Sandbox called pyScr.
      • --- refines the slit centers output by a Gaussian fit to the slit profile (IRAF's imexam 'j') using the max/min gradient method encoded in the centerSlit function of modsAlign
      • --- linear least squares fits to the set of star and slit centers. Fits are to x = m*y + c (not y = m*x + c) to avoid division by zero when centers are exactly lined up along a column. The angles are from the positive Y axis to the line of centers, and the recommended adjustment of the rotator zeropoint is the difference between the angle for the star images and slit image.
    • Usage:
      • make a file containing the filenames of field images between which the telescope was offset along the slit (detxy 0 dY). ls mods2r.20150511.000[1-9] mods2r.20150511.0010.fits > scan1.list
      • copy the slit image to a memorable name, e.g. cp mods2r.20150511.0011.fits slit1.fits
      • epar slitscan, enter the name of the list and the slit image. qbias = "yes" will run modsQB, producing a new image with the filename suffix, "_qb". If the quick-bias subtracted file already exists, quick bias will not be run again. Enter ":wq" to save parameters and exit from "epar".
                                            I R A F  
                             Image Reduction and Analysis Facility
PACKAGE = system
   TASK = slitscan

(inlist =               @scan1.list) List of field images
(slitima=           slit1.fits) Slit image
(qbias  =                  yes) Quick Bias images?
(verbose=                  yes) Verbose output to screen?
(imglist=                     )
(flist  =           tmp34393jf)
(tmp    =                     )
(mode   =                   ql)
      • run slitscan.
        • First the quick-bias subtraction will be done, if needed.
        • Then, the images will be co-added, if that has not been already done.
        • The coadded image will be displayed and an "imexam" session will be started.
          • Select a star. Position the cursor on each image of that star and type "a" to measure the set of centroids for the series of images between which the detxy +Y offset was made. Click "q" to exit "imexam".
        • Next, the slit image will be displayed and an "imexam" session started.
          • Position the cursor on the slit and type "j". Do this for several positions along the slit and then type "q" to exit "imexam". This will result in a series of slit centers, where the X center is the peak of the Guassian fit to the slit profile. These values are sent to the python script,, for refinement.
        • The screen output will look like:
Line of star centroids is 0.67996 degrees CCW from Y axis
Slit is                   0.14249 degrees CCW from Y axis
0.53748 degrees should be added to the current rotator zeropoint 

MODS: astrometry (not yet on the obs computers)

  • run in LBTtools.Sandbox (not yet on the mountain)
    • Dependencies:
      • modsQB --- "quick-bias" subtract to level out the quadrants and remove most of the even/odd effect.
      • cdsclient --- to query Vizier for an astrometric catalog, from the Stone (I/253) or the USNO-B1 (USNO-B1) catalogs. Any other catalog can be specified by its letter/number designation within the Vizier database. Among the columns returned are the calculated ra/dec, which do incorporate proper motions.
      • SExtractor --- 4 files are needed for running SExtractor:, modsastrom.param, gauss_5.0_9x9.conv and default.nnw. The script will look for these files in the modsastrom_dependencies subdirectory of Sandbox.
    • ccxymatch and ccmap to do the detections-to-catalog matching and transform.
    • Example parameter set:
                                            I R A F  
                             Image Reduction and Analysis Facility
PACKAGE = Sandbox
   TASK = modsastrom

(inimage= mods1r.20110928.0015) Input image
(qbias  =                  yes) Quick Bias image?
(FWHMini=                  1.2) Initial FWHM in arcsec
(dblpass=                  yes) Use double-pass (better, but slower)?
(getastc=                  yes) Get astrometric catalog (via cdsclient)?
(cdsname=                I/263) CDS catalog identifier (Stone=I/263;USNO-B1.0=USNO-B1)
(verbose=                  yes) Verbose output to screen?
(imglist=                     )
(flist  =                     )
(tmp    =                     )
(mode   =                   ql)

  • run a series of scripts written by Rick Pogge which use WCStools imwcs to do the matching and transform
    • more robust in matching
    • append the WCS to the header in a different way than IRAF ccmap, using keywords which better follow the current FITS standard for the WCS.
    • but, the WCS-updated image is not displayed correctly by ds9 v7.1 (N is up and E to the right, not left). It is displayed correctly in the latest ds9, v7.3.2.

-- %USERSIG{OlgaKuhn - 2015-08-04}%


Topic revision: r1 - 04 Aug 2015, OlgaKuhn
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