spectrographer

A spectrographer is a person who collects and analyzes spectra using a spectrograph, an instrument that disperses light into its component wavelengths. Spectrography is used across astronomy, chemistry, physics, and materials science. The term can refer to a technician who operates the instrument or to a researcher who specializes in spectroscopy.

A spectrographer operates the instrument, selects the light source, calibrates wavelength scales with reference lamps, records spectra on photographic media or, since the late 20th century, on electronic detectors such as CCDs, and analyzes spectral lines to determine wavelengths, intensities, and line shapes. They may also compute physical properties from spectra, such as chemical composition, temperature, density, or motion via Doppler shifts.

In astronomy, spectrographers use telescopes to collect starlight, galaxies, or nebulae, feed it into a spectrograph, and interpret absorption and emission lines to identify elements and ions, measure redshifts, stellar velocities, magnetic fields, and atmospheric parameters. This work supports stellar classification, galaxy studies, and the understanding of cosmic chemical evolution.

In chemistry and materials science, spectrographers employ emission or absorption spectroscopy to quantify concentrations, identify substances, or study electronic structure. Instruments range from handheld devices to high-resolution, laboratory-scale spectrographs connected to advanced detectors and data systems.

Historically, the practice developed with the invention of the spectrograph in the 19th century and the refinement of diffracting elements. Modern spectrography relies on digital detectors and software for calibration, reduction, and interpretation of spectral data.