The Use of Color Sensors for Spectrographic Calibration

TL;DR

This paper proposes a novel calibration method for spectrographs using color sensors instead of spectral features, enabling simpler, full-path calibration suitable for long-term applications like radial velocity astronomy and other scientific fields.

Contribution

It introduces a color-based calibration technique that simplifies spectrograph calibration by utilizing broad-spectrum light sources, reducing complexity and potential errors.

Findings

Color sensors can effectively calibrate spectrographs using broad-spectrum light.

The method reduces calibration complexity and equipment requirements.

Potential applications extend beyond astronomy to biology and chemistry.

Abstract

The wavelength calibration of spectrographs is an essential but challenging task in many disciplines. Calibration is traditionally accomplished by imaging the spectrum of a light source containing features that are known to appear at certain wavelengths and mapping them to their location on the sensor. This is typically required in conjunction with each scientific observation to account for mechanical and optical variations of the instrument over time, which may span years for certain projects. The method presented here investigates the usage of color itself instead of spectral features to calibrate a spectrograph. The primary advantage of such a calibration is that any broad-spectrum light source such as the sky or an incandescent bulb is suitable. This method allows for calibration using the full optical pathway of the instrument instead of incorporating separate calibration equipment that may introduce errors. This paper focuses on the potential for color calibration in the field of radial velocity astronomy, in which instruments must be finely calibrated for long periods of time to detect tiny Doppler wavelength shifts. This method is not restricted to radial velocity, however, and may find application in any field requiring calibrated spectrometers such as sea water analysis, cellular biology, chemistry, atmospheric studies, and so on. This paper demonstrates that color sensors have the potential to provide calibration with greatly reduced complexity.