distortion of line profile ?

Forums Spectroscopy What wavelength error is acceptable with an Alpy? distortion of line profile ?

Robin Leadbeater

The errors are within the FWHM of the slit image so I wonder if it could be something distorting the line profile eg :-

Coma from the ALPY camera lens distorting the line shapes more at the edges, which will depend on the f ratio of the incident light and appear as a variation in dispersion.

On stars, some sort of  chromatic aberration in the telescope optics producing a wavelength dependent asymmetry in the psf of the star which alters the distribution of light across the slit and hence the line profile.