field distortion check

Forums Spectroscopy LASER experiments and spectral calibration field distortion check

Derek Robson

I haven’t processed the images in BASS, ISIS or RSpec yet (I don’t have RSpec but maybe get it).  Just by eye, looking at the green, red and blue LASERs, the first order diffraction falls into that colour along a spectrum of Vega or Sirius. I read recently of one of the astro spectroscopists who did the opposite of what I did. He measured the wavelength of a green laser with a spectrophotometer using a calibration lamp.  For a green laser he used, he was spot on to within 0.1 nm of the stated wavelength, and that result was probably well within the experimental error of the determination.  I don’t know how much they vary in quality between products.  I’ve read that many are reliable in wavelength and bandwidth. Isn’t the process required to stimulate the radiation the same i.e. it is a specific atomic de-excitation that causes the light, and it’s energy (frequency or wavelength) is well-defined by chemistry and physics of the energy levels of the elements used in the LASER. Green and blue tend to be of one wavelength, whereas red ones fall into more than one category of wavelength, depending on which one it is.  That was a problem I encountered with my red LASER, I didn’t know which it was, but it was a standard collimation LASER. For the purposes of identifying elements in meteor spectra, I think they are still likely to do the job because some element lines can be identified relative to each other, even if the calibration is out a bit or a lot.