Alioth Spectrum

Forums Spectroscopy Introduction to spectroscopy Alioth Spectrum

Andy Wilson

That is a nice spectrum of Alioth on your member page, showing the hydrogen absorption lines.

Stacking is useful for fainter targets to increase the signal. However, you need good tracking for it to work well with a star analyser, to avoid any drift of the star. If there is even a slight drift then this can blur the spectrum, which might be what you were seeing. One way to reduce the problem is to align the wavelength axis of the spectrum North South, on the assumption that any drift will be East West. This could even help by spreading the spectrum over a few pixels, but requires that you have no drift in the North South direction.

Sharpening should normally be avoided. The algorithms can introduce artefacts and change the line profiles. I have heard of it occasionally being used to bring out faint lines, but it is very risky and will invalidate most of the scientific data contained within the spectrum.