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Recipe catalogue

17 recipes discoverable by this build of the documentation (spectro-kernel 0.8.1): the ones bundled with the kernel plus the installed collections. Each page lists the recipe's conventions, references, variables and steps, and how to run it from the CLI, Python or MCP. The same catalogue is available as JSON; the file format is described by preset.schema.json.

Status legend: reference = reviewed and adopted as the reference way to make this measurement; reviewed = conventions documented; draft = open for discussion. See Share a recipe for how a recipe moves up.

Campaign recipes

Recipe What it measures Status Version Variables Source
be_halpha_ew H-alpha equivalent width and V/R ratio of a Be star on a reduced, wavelength- calibrated spectrum: the wavelengths are brought to the barycentric frame from the header and the observer's site, the continuum is set on a line-free band on the blue side of the line, the equivalent width is integrated over a fixed window with the Vollmann & Eversberg (2006) error, and the V/R ratio of a double-peaked profile is measured. Every observer who runs this recipe measures the same quantity the same way, whatever the instrument; only the site coordinates come from the observer's profile. draft 1.0.0 3 package:spectro-kernel-recipes
be_line_profile_variability Temporal variance spectrum of the H-alpha profile of a Be star over a series of epochs (Fullerton, Gies & Bolton 1996): where, in velocity, the line profile varies significantly from night to night, and how strongly. Runs on a set of continuum-normalised spectra, typically the epochs of a multi-observer campaign already brought to the same normalisation by be_halpha_ew. draft 1.0.0 0 package:spectro-kernel-recipes
binary_rv_ccf Radial velocity of a star by cross-correlation against a template, for the follow-up of spectroscopic binaries and exoplanet hosts: barycentric correction from the header, continuum normalisation, then the Tonry & Davis cross-correlation on a log-wavelength grid sampled at the native resolution. draft 1.0.0 4 package:spectro-kernel-recipes
nova_balmer_decrement Nebular extinction of a nova, symbiotic star or H II region from the observed H-alpha / H-beta Balmer decrement on a reduced, flux-calibrated (or at least relatively calibrated) spectrum: the two line fluxes are fitted, compared with the Case B intrinsic ratio, and turned into c(H-beta), E(B-V) and A_V with the CCM89 law. The same conventions for every observer of the campaign. draft 1.0.0 0 package:spectro-kernel-recipes
star_activity_caii_hk Mount Wilson S index from the Ca II H and K line cores of a reduced stellar spectrum (Vaughan, Preston & Wilson 1978), and log R'_HK when the star's B-V colour is given (Noyes et al. 1984). The standard chromospheric activity measurement for exoplanet-host and solar-type star monitoring. draft 1.0.0 2 package:spectro-kernel-recipes
star_activity_halpha H-alpha chromospheric activity index of a reduced stellar spectrum, after Gomes da Silva et al. (2011): the mean flux in a 1.6 Angstrom core over the sum of two nearby continuum bands. The red-arm companion of the Ca II H and K S index, usable on any spectrograph that covers H-alpha. draft 1.0.0 0 package:spectro-kernel-recipes
star_vsini_fourier Projected rotational velocity v sin i of a star from the first zero of the Fourier transform of one isolated absorption line (Carroll 1933; Gray 2005), on a continuum-normalised, reduced spectrum. The line, its window and the limb-darkening coefficient depend on the star and on your resolution, so they are variables. draft 1.0.0 3 package:spectro-kernel-recipes

Reduction recipes

Recipe What it measures Status Version Variables Source
full_reduction_easyspec Full CCD-to-1D reduction routed through the EasySpec shelf: build the master bias / dark / flat, apply them to the science frame, remove cosmic rays and extract a 1-D pixel-index spectrum. Wavelength calibration, atmospheric extinction and flux calibration are separate steps afterwards because each needs runtime metadata (arc-lamp identifications, airmass, standard star). Everything that depends on your night lives in the variables below: supply them with a profile (--profile night.yaml) or --set name=value. reference 2.0.0 10 bundled
solar_long_slit Long-slit solar reduction from a raw 2-D frame: geometric rectification, hot-pixel rejection, band extraction (the Sun fills the slit), wavelength calibration on the Fraunhofer lines (no lamp needed), continuum normalisation and BeSS export. The instrument geometry and the exposure metadata are variables, so one profile per spectrograph serves every solar spectrum. draft 1.0.0 11 package:spectro-kernel-recipes
stellar_long_slit Long-slit stellar reduction from a raw 2-D frame with an arc lamp: geometric rectification, hot-pixel rejection, sky subtraction on both sides of the trace, aperture extraction, polynomial wavelength solution from the lamp identifications, continuum normalisation and BeSS export. draft 1.0.0 12 package:spectro-kernel-recipes

Analysis recipes

Recipe What it measures Status Version Variables Source
balmer_quick Quick analysis of the Balmer lines (H-alpha, H-beta, H-gamma) on an already-loaded spectrum: normalise the continuum, estimate SNR, then fit a Gaussian to each line. reference 1.0.0 0 bundled
embed_quick Normalise the continuum and embed the spectrum into a 256-d searchable vector. Drop this pipeline on any single spectrum to get a ready-to-index embedding with its provenance recorded on the context. reference 1.0.0 0 bundled
lamp_resolving_power Resolving power R = lambda / FWHM of a spectrograph from an extracted, wavelength-calibrated arc-lamp (or sky-emission) spectrum: Gaussian fits of the strongest isolated lines, median R and its scatter, and the instrumental FWHM in Angstrom and km/s. A quality-control measurement to report with every campaign submission (BeSS asks for the resolution of each spectrum). draft 1.0.0 0 package:spectro-kernel-recipes
quality_report Three independent SNR estimates on the same spectrum: derivative-based (DER_SNR), edge-region, and residual of a linear fit. Disagreement between them is a useful diagnostic of bad regions or strong features. reference 1.0.0 0 bundled
rv_quick Quick radial-velocity measurement from H-alpha on an already-loaded spectrum: normalise the continuum, then fit the line and turn its centroid shift into a velocity in km/s. reference 1.0.0 0 bundled
snr_check Quick data-quality check on an already-loaded spectrum: normalise the continuum, then report the signal-to-noise ratio with two independent estimators. reference 1.0.0 0 bundled
time_series_overview Stack many epochs of the same target into one master spectrum and render a dynamic-spectrum heatmap, a 3D surface and an animated frame-by-frame view — the three complementary visualisations of spectral variability. reference 1.0.0 0 bundled