• normPlot: a tool for normalizing stellar spectra, with an interactive GUI, written by Colin Folsom

Least Squares Deconvolution (LSD) is a technique similar to cross-correlation, which extracts an average spectral line profile from a spectrum (polarised or unpolarised) using an input line list. The algorithm is described and its performances analysed in: Donati et al. (1997) and Kochukhov et al. (2010).

• LSDpy: python implementation of LSD written by Colin Folsom
• pylsd: python tools to create and manipulate LSD line lists written by Julien Morin

Zeeman-Doppler Imaging (ZDI) is a tomographic imaging technique which aims at reconstructing a map of the vector magnetic at the stellar photosphere from a time-series of polarised spectra. The algorithm and first tests has been introduced in the seminal papers Semel (1989) and Donati, Semel & Praderie (1989). Tests of the method and further improvements are discussed in subsequent papers such as: Brown et al. (1991), Donati et al. (1997), Donati et al. (2006).

• ZDIpy: python implementation of ZDI written by Colin Folsom, following the method of Donati et al.
  • the code is described in Folsom et al. (2018)