MODS2 Guide Camera Photometric and Astrometric Performance

20140430: Data on PG1657 were collected through Clear and B_Bessel filters

Photometric skies, but poor seeing, ~2".

Preparing to take the data (Scripts, Catalogs)

Images are right_guider0000NN_dd.fits where the dd images have header info: gethead right_guider0000*dd.fits filter exptime telra teldec

Note that the filter, if changed via MODS, is not changed in GCS!!!

I ran IDL script,, on the *.pos and *.pho catalogs downloaded from Stetson's UBVRI standards at CADC to locate several 40" x 40" (0.66' x 0.66') fields, within PG1657, which had 2-3 stars.

do_nn_stetson,nth=2,fov=0.33,mlim=20 (attached)

This output a set of 17 fields. Attached is the output from this call using an improved do_nn_stetson which outputs also the star name, B and B-R.

Doug created:
  • a catalog with entries for these 17 stars. It is M92 catalog (the name is from the earlier dense astrometric field that we tried).
    • /home/lbto/idl/catalogs/irtc/catalogs/M92.catalog
    • Also a pared down catalog with only the brightest stars of these 17 PG1657b.catalog (both attached)
  • and a script which will loop through the entries of this catalog, send an ACQUIRE preset, stop acquire, and take an acquisition image.
    • mods_list_preset, M92, retval
pro mods_list_preset, target, retval
 for i=5,14 do begin
   iif_preset, target, MODE="ACQUIRE", TS=i, GS=i
   spawn, 'stopAcquire right', result
   gcs_take_image, filename, retval, EXP=30.0, /Right, /Guider

Taking the data

Data have been copied to /home/lbto/MODS2Comm/20140430_guiderData.

The sequence of right_guider0000NN.fits images are:

NN=31 This one is on M92 (17:17 +42)... no header info.

Then we added to M92.catalog a series of stars in PG1657 and ran a test script.

NN=32 16:59:25.29 +07:42:45.35 33 34 35-38 were the 4 done at PG1657

Around 4am running a series of observations on stars in PG1657 M92.catalog in /home/lbto/idl/catalogs/irtc/catalogs/M92.catalogs but on PG1657:

Clear filter: 39,40,...55, exptime = 10-sec

Clear filter: 56, ... 72, exptime = 30-sec

deleted stars with mag >= 19 from list, now only 11 (10) stars

B_Bessel filter: 73 ... 83 (in twilight), exptime = 30-sec.

Data in /home/lbto/MODS2Comm/20140430_guiderData
  • PG1657_stardata.list
  • PG1657_clrBphot.list is a listing of the images, with comments and with star names and B mag, B-R colors.
  • PG1657phot.jpg (series of clear 30-sec images)
  • PG1657phot.jpg (finder chart)
    • ds9 -dsssao size 10 10 arcmin -dsssao coord 16:59:35.36 +07:42:25.0 sexagesimal -regions PG1657_clip.reg &

20140503: Data on a dense region within M92 were collected through Clear, LP and B_Bessel filters

Preparing to take the data (Scripts, Catalogs)

  • Selected a dense field within M92, using as a base the catalog of M92 (=NGC6341) from Stetson's UBVRI standards at CADC.
    • do_nn_stetson, nth=20, fov=0.33, mlim=17
      • this is based on the IDL program which D Thompson wrote to search for fields which have the Nth nearest neighbor within a FOV of radius fov
      • output 1 field with center at ra(J2000), dec(J2000) = 17:17:5.229 +43:08:59.3 and having 13 catalog stars within a 40" x 40" region
        • (notes: the projection was not exactly correct in outputting these lists, so there may be +/- xx stars)
  • _to be completed ... _
    • will attached subset of M92 catalog (positions, BVI photometry), finding chart and an image with catalog stars circled.

Taking the data

  • Data are right_guiderimage0000NN.fits, copied into /home/lbto/MODS2Comm/GuiAstrom/Data/20140503/


  • To come...

-- %USERSIG{OlgaKuhn - 2014-05-01}%
Topic revision: r2 - 23 May 2014, OlgaKuhn
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