gfaproc

Overview

Astrometrically calibrates the GFA acquisition images, determines the pointing correction needed to center the field on the focal plane, determines the pixel coordinates for a set of guide stars when the telescope is at the correct pointing, and computes the sky coordinates of the GFA fiducials would have at that pointing.

Input

Arguments

nfs_data

miscelaneous paramaters associated with the sequences, generally set in PlateMaker by running nfsproc prior to running gfaproc.

gfa_images

image data from the GFA system

targets

the targets (including astrometric standard stars for the sequence)

Configuration

TODO

Output

gfa_guide

the expected pixel positions of guide stars

gfa_center

the pointing correction needed to center the focal plane on the field

gfa_data

GFA solution and miscelaneous parameters

gfa_wcs

FITS WCS parameters for the GFA image

guider_wcs

Expected FITS WCS parameters for guider images

Return value

Either SUCCESS if the the caluculation is successful, or an error message othewise.

Use

First, a PML connection must be established:

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

For this demonstration, load some sample data for the input:

>>> from PlateMaker import test_data
>>> seq_id = test_data.seq_id
>>> nfs_data = test_data.nfs_data
>>> gfa_images = test_data.gfa_images
>>> targets = test_data.targets

Actually execute gfaproc:

>>> pm.execute('set', seqid=seq_id)
'SUCCESS'
>>> pm.execute('gfaproc',
...            nfs_data=nfs_data,
...            gfa_images=gfa_images,
...            targets=targets)
'SUCCESS'

The results of the calculations can then be retrieved:

>>> gfa_guide = pm.execute('get', 'gfa_guide')
>>> gfa_center = pm.execute('get', 'gfa_center')
>>> gfa_data = pm.execute('get', 'gfa_data')
>>> gfa_wcs = pm.execute('get', 'gfa_wcs')
>>> guider_wcs = pm.execute('get', 'guider_wcs')