Holiday Present for the Observatory December 15, 2009Posted by jcconwell in Observatory.
Tags: EIU, Observatory, spectra
The end of the semester is here and the physics students are completing their projects for their third semester senior advanced lab. The third semester is an independent project (read: “give them enough rope to hang themselves”). This semester Alicia made a nice present for the observatory’s spectrometer. A Calibration source.
The spectrometer and camera are sort of dumb. When we take a picture of a star’s spectra the camera assigns a spectral line to a column of pixels on the camera, but it doesn’t know the wavelength corresponding to that column. What Alicia made is a combination Mercury-Neon lamp, that feeds the light through a fiber optic wire directly into the spectrometer. The Mercury for the blue end and Neon for the red end of the spectra. We then take a picture of the combination Hg-Ne spectra (whose wavelengths are known) and the computer uses those lines to assign the wavelengths to each column of pixels, thus calibrating it .
We ‘ll now be able to do this from the nice warm control room. No more trudging up to the telescope at 2:00AM, in below zero weather to shine a Hg lamp and take a calibration spectra!