The Limits of Solar Observation

Abstract

The Sun is the closest star to us by far, and the only one upon which we can easily see fine detail. It also provides us with vast numbers of photons at all wavelengths. The astronomer’s usual problem of picking out the few desired photons from the welter of background photons from other sources is thus often replaced by having to cut down the intensity from the Sun. The abundance of energy and detail has led to many specialised instruments being developed for solar work which cannot be used in normal astronomy. We have seen some of these (Chapter 8): coronagraphs, Hα filters, spectrohelio-scopes, prominence spectroscopes, etc., which are within the reach of amateur astronomers, even if in some cases it is at the outer limits of the bounds of possibility. There are many more specialised instruments which are the province purely of the professional astronomer either through cost, the background equipment and knowledge that is needed to operate them and analyse their data, the need for a remote site or a large support team, etc.