get_atran

sofia_redux.instruments.exes.get_atran.get_atran(header, resolution, filename=None, get_unsmoothed=False, atran_dir=None)[source]

Retrieve reference atmospheric transmission data.

PSG model files in the data/transmission directory should be named according to the altitude, ZA, and wavelengths for which they were generated, as:

psg_[alt]K_[za]deg_[wmin]-[wmax]um.fits

For example, the file generated for altitude of 41,000 feet, ZA of 45 degrees, and wavelengths between 5 and 28 microns should be named:

psg_41K_45deg_5-28um.fits

Model files are expected to be FITS images containing two rows. The first is wavenumber values in cm-1; the second is the fractional atmospheric transmission expected at that wavenumber.

The procedure is:

  1. Identify model file by ZA and Altitude, unless override is provided.

  2. Read transmission data from file and smooth to expected spectral resolution.

  3. Return transmission array.

Parameters:
headerastropy.io.fits.header.Header

ATRNFILE keyword is written to the provided FITS header, containing the name of the model file used.

resolutionfloat

Spectral resolution to which transmission data should be smoothed.

filenamestr, optional

Atmospheric transmission file to be used. If not provided, a default file will be retrieved from the data/transmission directory. The file with the closest matching ZA and Altitude to the input data will be used. If an override file is provided, it should be a FITS image file containing wavenumber and transmission data without smoothing.

get_unsmoothedbool, optional

If True, return the unsmoothed atran data with original wavenumber array in addition to the smoothed array.

atran_dirstr, optional

Path to a directory containing model reference FITS files. If not provided, the default set of files packaged with the pipeline will be used.

Returns:
atrannumpy.ndarray

A (2, nw) array containing wavenumber and transmission data.

unsmoothednumpy.ndarray, optional

An array containing wavenumber, unsmoothed transmission data, and any additional raw data rows, returned only if get_unsmoothed is set.