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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).
Kind analysis
Status draft - draft: conventions still open for discussion
Version 1.0.0
Source package:spectro-kernel-recipes
Requires spectro-kernel >=0.7

Conventions

The ten strongest lines isolated by at least 5 Angstrom from any other detection, fitted within +/- 3 Angstrom, detected above 5 times the noise; lines closer than 5 Angstrom to a neighbour are excluded as blends.

References

  • Gray 2005, The Observation and Analysis of Stellar Photospheres, 3rd ed., ch. 12 - resolving power from the instrumental profile
  • Tody 1986, Proc. SPIE 627, 733 - IRAF splot Gaussian line measurement

Variables

This recipe declares no variables: it runs as is.

Steps

# Algorithm Parameters
1 measure_resolving_power Resolving power from the isolated lamp lines n_lines=10, min_separation_aa=5.0, window_aa=3.0

Run it

spectro pipeline lamp_resolving_power --input spectrum.fits
spectro preset show lamp_resolving_power      # variables and steps

from spectro_kernel import WorkContext
from spectro_kernel.pipeline import PipelineBuilder

pipeline = PipelineBuilder().from_preset("lamp_resolving_power").build()
result = pipeline.execute(ctx)        # ctx holds the spectrum / frames
print(result.history[-1])             # pipeline:<name> vX.Y.Z + variables

{
  "tool": "run_preset",
  "arguments": {
    "session_id": "<session_id>",
    "preset_name": "lamp_resolving_power"
  }
}