5.1.2. Spectral Extraction (extract)

Introduction

Spectral extraction refers to the conversion of two-dimensional spectroscopic image(s) to a one-dimensional, fluxed spectrum. While there are many discussions of this process in the literature (e.g. Horne 1986), many of these focus on aperture-based spectrographs (e.g. long-slits or fibers). Certainly, many of the aspects of the reduction/analysis of these data are applicable or have corollaries to slitless spectrographs, but the lack of an aperture leads to many complicating factors.

Preprocessing WFSS Images

Before one can extract WFSS data, there are several preprocessing steps that should considered. Below is a table that lists the three major preprocessing steps that one should implement for their data:

• Astrometry
• Background Subtraction
• Cosmic Rays

How to extract the data?

Slitlessutils offers two modes for extracting one-dimensional spectra from a collection of WFSS images. The primary difference between the two is based on the number of distinct orients (or dispersion directions) available.

• Single-Orient Extraction (Single())
• Multi-Orient Extraction (multi)