Here We Go

An alternative title of this material could be “The Data Everyone Would Like to Get for their Research!” The first thing we seem to do in astronomy is ‘see’ something, be it simply looking in the sky, using a big telescope, or helping ourselves with sophisticated adaptive optics or space probes. But the very next thing we want to do is get that light into a spectrograph! We might get spectral information from colors, energy distributions, modest resolution or real honest high resolution spectroscopy, but we desperately need such information. Why? Well, because that's where most of the physical information is, and higher spectral resolution means access to more and better information. High resolution implies actually resolving the structure of the spectrum. Naturally we want to do this as precisely as possible, not only pushing toward good spectral resolution and high signal-to-noise, but also by understanding how the equipment has modified the true spectrum and by weeding out problems and undesirable characteristics. The main focus here will be on the machinery of spectroscopy, but oriented toward optical spectrographs and the spectral lines they are best suited to analyze. I do not concentrate on the specific instruments, but rather on the techniques and thought patterns we need. These are the fundamental things you can take with you and apply to any spectroscopic work you do. Of course, you will always have to fill in specific details for the particular machinery and tools you use.