Observation format

This section will help you convert your observationnal data into the ForMoSA format

Imports

from astropy.io import fits
from astropy.table import Table

Data .fits

Your observed data (spectroscopy and/or photometry) should be formated in a .fits file with the following extensions :

• ‘WAV’ : (array) wavelength grid.

• ‘FLX’ : (array) flux.

• ‘ERR’ or ‘COV’ : (array or 2D-array) errors or covariance matrix. The covariance matrix should have diag(COV)=ERR².

• ‘RES’ : (array) resolution. Note : You must put res = 0.0 where you have photometric points.

• ‘INS’ : (array) instrument name. Note : You must use the right filter name when you have photometric points. Check the phototeque for more information.

exemple :

# CHECKUP FORMAT
hdul = fits.open('~/YOUR/PATH/formosa_desk/inversion_targetname/inputs/data.fits')
print(hdul[1].columns)
wav = hdul[1].data['WAV']
flx = hdul[1].data['FLX']
err = hdul[1].data['ERR']
res = hdul[1].data['RES']
ins = hdul[1].data['INS']

ColDefs(
    name = 'WAV'; format = 'D'
    name = 'FLX'; format = 'D'
    name = 'ERR'; format = 'D'
    name = 'RES'; format = 'D'
    name = 'INS'; format = '3A'
)

optional extensions can also be used when dealing with stellar-contaminated high-resolution spectroscopy:

• ‘TRANSM’ : (array) transmission (atmospheric + instrumental)

• ‘STAR_FLX’ or ‘STAR_FLXi’ : (array or i arrays) star flux or shifted star flux (to account for LSF changes)

• ‘SYSTEM’ or ‘SYSTEMj’ : (array or j arrays) systematic model(s) (usually computed from PCA)

Format your data

To format your data, you can use the simple Python routine below :

# FITS converter :
table = Table([wav, flx, res, res, ins], names=('WAV', 'FLX', 'ERR', 'RES', 'INS'))
hdul = fits.HDUList()
hdu = fits.BinTableHDU(table)
hdul.append(hdu)
hdul.writeto('~/YOUR/PATH/formosa_desk/inversion_targetname/inputs/data.fits')
print('correction successful')

correction successful

If you have multiple observations, we recommand that you create separated .fits files (e.g data_1.fits, data_2.fits, …)