William Herschel: Observation

“I have availed myself of the labors of preceding astronomers, but have been induced thereto by my own actual observation of the solar phenomena.”

William Herschel

Source: Sir William Herschel: His Life and Works (1880), Ch.4 "Life and Works" quote from his paper "Nature and Construction of the Sun and Fixed Stars" (1795).
Context: I should not wonder if, considering all this, we were induced to think that nothing remained to be added; and yet we are still very ignorant in regard to the internal construction of the sun.... The spots have been supposed to be solid bodies, the smoke of volcanoes, the scum floating on an ocean of fluid matter, clouds, opaque masses, and to be many other things.... The sun itself has been called a globe of fire, though, perhaps, metaphorically.... It is time now to profit by the observations we are in possession of. I have availed myself of the labors of preceding astronomers, but have been induced thereto by my own actual observation of the solar phenomena.<!-- p. 145-146

“A knowledge of the construction of the heavens has always been the ultimate object of my observations…”

William Herschel

Astronomical Observations relating to the Construction of the Heavens... (1811)

Knowledge

“It will be necessary to explain the spirit of the method of arranging the observed astronomical objects under consideration in such a manner, that one shall assist us to understand the nature and construction of the other.”

William Herschel

Astronomical Observations relating to the Construction of the Heavens... (1811)
Context: It will be necessary to explain the spirit of the method of arranging the observed astronomical objects under consideration in such a manner, that one shall assist us to understand the nature and construction of the other. This end I propose to obtain by assorting them into as many classes as will be required to produce the most gradual affinity... and it will be found that those contained in one article, are so closely allied to those in the next, that there is perhaps not so much difference between them... as there would be in an annual description of the human figure were it given from the birth of a child till he comes to be a man in his prime.<!-- p. 270-271

Understanding , Nature

“The number of compound nebulæ… being so considerable, it will follow, that if they owe their origin to the breaking up of some former extensive nebulosities of the same nature with those which have been shewn to exist at present, we might expect that the number of separate nebulæ should far exceed the former, and that moreover these scattered nebulas should be found not only in great abundance, but also in proximity or continuity with each other… Now this is exactly what by observation, we find to be the state of the heavens.”

William Herschel

p, 125
Astronomical Observations relating to the Construction of the Heavens... (1811)

Nature

“In the year 1783 I finished a very good twenty-foot reflector with a large aperture, and mounted it upon the plan of my present telescope. After two years' observation with it, the great advantage of such apertures appeared so clearly to me that I recurred to my former intention of increasing them still further; and being now sufficiently provided with experience in the work which I wished to undertake, the President of the Royal Society, who is always ready to promote useful undertakings, had the goodness to lay my design before the king. His Majesty was graciously pleased to approve of it, and with his usual liberality to support it with his royal bounty.”

William Herschel

Source: Sir William Herschel: His Life and Works (1880), Ch.4 "Life and Works".

Support , Appearance

“These [binary stars] may serve another very important end…. Several stars of the first magnitude have been observed or suspected to have a proper motion; hence we may surmise that our sun, with all its planets and comets, may also have a motion towards some particular point of the heavens…. If this surmise should have any foundation, it will show itself in a series of some years in a kind of systematical parallax, or change due to the motion of the whole solar system.”

William Herschel

Source: Sir William Herschel: His Life and Works (1880), Ch.4 "Life and Works" quote from "Researches on the Motion of the Sun and of the Solar System in Space" (1782), p. 149

Star , Change , Sun

“Here [in Slough], soon after my arrival, I began to lay the foundation upon which by degrees the whole structure was raised as it now stands, and the speculum being highly polished and put into the tube, I had the first view through it on February 19, 1787. …the first speculum, by a mismanagement of the person who cast it, came out thinner on the centre of the back than was intended, and on account of its weakness would not permit a good figure to be given to it. …A second mirror was cast January 26, 1788, but it cracked in cooling. February 16 we recast it, and it proved to be of a proper degree of strength. October 24 it was brought to a pretty good figure and polish, and I observed the planet Saturn with it. But not being satisfied, I continued to work upon it till August 27, 1789, when it was tried upon the fixed stars, and I found it to give a pretty sharp image. Large stars were a little affected with scattered light, owing to many remaining scratches on the mirror. August the 28th, 1789, having brought the telescope to the parallel of Saturn, I discovered a sixth satellite of that planet, and also saw the spots upon Saturn better than I had ever seen them before, so that I may date the finishing of the forty-foot telescope from that time.”

William Herschel

Source: Sir William Herschel: His Life and Works (1880), Ch.4 "Life and Works".

Star , Light , Time , Personality