get_atran

sofia_redux.instruments.forcast.getatran.get_atran(header, resolution, filename=None, get_unsmoothed=False, use_wv=False, atran_dir=None, wmin=4, wmax=50)[source]

Retrieve reference atmospheric transmission data.

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

atran_[alt]K_[za]deg_[wmin]-[wmax]mum.fits

For example, the file generated for altitude of 41,000 feet, ZA of 45 degrees, and wavelengths between 40 and 300 microns should be named:

atran_41K_45deg_40-300mum.fits

If use_wv is set, files named for the precipitable water vapor values for which they were generated will be used instead, as:

atran_[alt]K_[za]deg_[wv]pwv_[wmin]-[wmax]mum.fits

The procedure is:

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

  2. Read ATRAN 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 ATRAN file used.

resolutionfloat

Spectral resolution to which ATRAN data should be smoothed.

filenamestr, optional

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

get_unsmoothedbool, optional

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

atran_dirstr, optional

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

use_wvbool, optional

If set, water vapor values from the header will be used to select the correct ATRAN file.

wminint, optional

Wavelength minimum to match ATRAN file names.

wmaxint, optional

Wavelength maximum to match ATRAN file names.

Returns:
atrannumpy.ndarray

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

unsmoothednumpy.ndarray, optional

A (2, nw) array containing wavelengths and unsmoothed transmission data, returned only if get_unsmoothed is set.