What is Astronomical Spectroscopy?

This webpage is being developed as a supplementary resource for the Yahoo Group Astronomical Spectroscopy



Many amateurs apply their resourses to achieving successful astrophotographic images. This takes some dedication and the ability to set up their mounting (polar alignment), telescope and camera to allow extended exposures with their DSLR/ CCD camera. Then comes the seeming endless task of processing the acquired images (darks/ bias/ flats/ colour balance etc.) to provide an enhanced acceptable image.

Spectroscopy makes use of a similar range of equipment and skills, with the addition of a transmission grating or slit spectrograph to obtain not an image of the stars, but the their spectrum.

The grating disperses the starlight into a visible spectrum. This spectral image generally covers the visible wavelengths from 370nm (3700A) through to 700nm (7000A). Depending on the type of star (or other object - nebula/ comets etc.) the spectrum recorded will have a brightness variation - usually brighter towards the middle and show dark lines across it's height. These two features can tell us about the nature and composition of the star. To make the analysis of this data easier, the spectrum is usually displayed as a graphical profile - intensity v's pixel position; this is then wavelength calibrated using various methods to provide an intensity v's wavelength outcome. This resulting profile is saved as a 1D fits file for future review and sharing with others. Good news is that this processing is in some ways is much easier than processing astrophotos, and the main software used is freeware.

Using the 1D fits we can compare our results with others, consult amateur and professional databases to provide further information and share the data with interested ProAm programs.

You don't need a degree in mathematics or science, just a willingness to learn. There are many support groups available to the amateur, as well as professionals who are more than happy to assist you in all aspects of spectroscopy. Your rewards are boundless. You are contributing to the science community and by your actions encouraging the next generation to follow suit.

A great overview of the wide scope of spectroscopy can be found here Spectroscopy Fundamentals

The How to... section will get you started and then you can select any of the other section to continue your searches.

Check out the Spectrograph area for more details on spectroscope design, availability of commercial instruments and the DIY construction and testing of various spectrographs. 

Recommended Books and further reading can be found here.

There are many very well presented and useful spectroscope websites already accessable to the amateur. These are listed in the Reference Material section and similar links are given within the various sections, these should be consulted frequently.