merged_fvc_spots

Overview

The target spot positions from the FVC.

Like fiber_pos, but actual measured position.

Creators

  • Fiber-View-Camera system
  • PlateMaker testing and simulation
    • fvcsim

Users

  • fvcproc
  • internal to PlateMaker
    • fvcAstrom
    • positionerDiff

Contents

Table columns

# name alt name type units description
1 serial   integer   unique identifier for all target and ETC (exposure time calculator) positioners
2 x x_pix float pixels fiber view camera coordinate, center of CCD at 0
3 y y_pix float pixels fiber view camera coordinate, center of CCD at 0
4 mag   float   astronomical magnitude
5 meas_err pos_err float   not meaningful
6 flags   int   see below

Storage and access

Through DOS

After the seqid is set, the set and get PML commands may be used to provide PlateMaker with the targets, and retrieve them back if wanted.

First, a PML connection must be established:

>>> from DOSlib.PML import dos_connection
>>> pm = dos_connection('PLATEMAKER')
>>> pm.execute('configure')
'SUCCESS'

and some sample data loaded:

>>> from PlateMaker import test_data
>>> merged_fvc_spots = test_data.merged_fvc_spots

The data are stored in a numpy.recarray:

>>> merged_fvc_spots.dtype
dtype((numpy.record, [('serial', '<i8'), ('x', '<f8'), ('y', '<f8'), ('mag', '<f8'), ('meas_err', '<f8'), ('flags', '<i8')]))

We need to set the seqid in PlateMaker to prepare it for working on a sequence:

>>> pm.execute('set', seqid=52254)
'SUCCESS'

Then we can set merged_fvc_spots:

>>> pm.execute('set', merged_fvc_spots=merged_fvc_spots)
'SUCCESS'

and get them back (not generally useful):

>>> retrieved_merged_fvc_spots = pm.execute('get', 'merged_fvc_spots')

Preferred file representation

Name template:fvcMerge-${SEQID}.dat
Format:whitespace delimited ASCII text

Example start of file contents

::
>>> from PlateMaker import test_data
>>> fname = test_data.data_dir + '/fvcMerge-52254.1.dat'
>>> print(open(fname, 'r').readline())
#serial  x_pix  y_pix  mag  pos_err  flags

>>> print(open(fname,'r').read()) 
#serial  x_pix  y_pix  mag  pos_err  flags
1100 -171.467 135.377 0. 0. 8
1118 -150.319 -186.370 0. 0. 8
1102 -110.903 301.163 0. 0. 8
1103 -69.492 -342.568 0. 0. 8
1117 -33.623 54.165 0. 0. 8
1106 -17.470 -96.834 0. 0. 8
1107 97.777 316.522 0. 0. 8
1108 118.208 -7.414 0. 0. 8
1116 140.145 -330.499 0. 0. 8
1115 223.291 431.989 0. 0. 8
1111 279.968 -429.376 0. 0. 8
1112 414.611 444.529 0. 0. 8
1113 548.071 -409.472 0. 0. 8
1114 717.169 -45.221 0. 0. 8
1101 532.567 -61.614 0. 0. 8
1109 200.032 284.161 0. 0. 8
3000 -2935.786 2796.600 0. 0. 36
3001 -23.483 1.892 0. 0. 4
3002 117.536 245.940 0. 0. 4
3003 117.435 -242.325 0. 0. 4