Published online by Cambridge University Press: 08 December 2022
Electromagnetic radiation is the primary source of astronomical information.
In particular, until the early 1930s astronomy was all based on the use of telescopes
that extended the power of the human eye, but were restricted to the
collection of visible light. In general, the sources of astronomical electromagnetic radiation and other sources of astronomical information are what we call visible matter. This chapter introduces some key concepts and notation that characterize light and the collection of light for astronomical purposes. It addresses the main types of information that we may extract from the observations, by means of imaging and spectroscopy, recalling the difference between apparent and intrinsic properties of the astronomical sources and the fact that the light from distant sources is often a mixture of photons from different stars or different
components. This serves as an excuse for a quick introduction to important
concepts, such as stellar populations, mass-to-light ratios, mean motions, and
velocity dispersions. In closing the chapter, a method is described to measure the distance to a stellar system based on the application of a very simple dynamical model to a suitable set of observations.
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.