OneSpec

Overview

Generally, the ultimate PypeIt spectrum output is a single spectrum per source, fully calibrated and (as desired) with a Telluric Correction performed.

The standard way to generate this file is with the pypeit_coadd_1dspec script script.

The naming of this file is user-generated, i.e. it can be anything you wish.

The header of the primary extension includes the core_meta of PypeIt, e.g. RA, DEC, MJD, and configuration parameters of the instrument.

In addition, for echelle spectrograph reductions, the PypeIt output will include the coadded orders for each echelle setup used per spectrum per source, fully calibrated but not yet telluric corrected. See OrderStack for more details.

Inspection

Use pypeit_show_1dspec to view the spectrum.

Current Data Model

Internally, the spectrum for a single object is held by the OneSpec class.

Here is its datamodel, which is written as an astropy.io.fits.BinTableHDU in the first HDU of the file.

Version: 1.0.2

Obj Key	Obj Type	Array Type	Description
PYP_SPEC	str		PypeIt spectrograph designation
ext_mode	str		Extraction mode (options: BOX, OPT)
flux	ndarray	floating	Flux array in units of counts/s or 10^-17 erg/s/cm^2/Ang; see fluxed
fluxed	bool		Boolean indicating if the spectrum is fluxed.
ivar	ndarray	floating	Inverse variance array (matches units of flux)
mask	ndarray	integer	Mask array (1=Good,0=Bad)
obj_model	ndarray	floating	Object model for tellurics
sigma	ndarray	floating	One sigma noise array, equivalent to 1/sqrt(ivar) (matches units of flux)
spect_meta	dict		header dict
telluric	ndarray	floating	Telluric model
wave	ndarray	floating	Wavelength array (angstroms in vacuum), weighted by pixel contributions
wave_grid_mid	ndarray	floating	Wavelength (angstroms in vacuum) evaluated at the bin centers of a grid that is uniformly spaced in either lambda or log10-lambda/velocity

All wavelengths are in vacuum and flux units depend on whether Fluxing was performed.