There are several others of the same type: these are not, properly speaking, variable stars.
Peck and his assistant, Mr. Grover, made many valuable observations of variable stars at the Rousden Observatory during many years past.
Algol, the most famous of these variable stars, at its maximum of brightness furnishes three times as much light as when at its minimum, and other variable stars show an even greater range.
Algol is one of the most conspicuous of these variable stars, as they are called.
Some of these are in common use to-day, by navigators, observers of meteors and of variable stars.
There are, however, other classes of variable stars, the fluctuation of whose light can hardly be due to occasional obscuration by dark bodies.
I observe from seven or eight till about two in the morning, with a view to my great work on variable stars.
Compared with comets, variable stars, which he had hitherto made his study, were, from their remoteness, uninteresting.
It was the review of a pamphlet by an American astronomer, in which the author announced a conclusive discovery with regard to variable stars.
During the first half of the nineteenth century Argelander so systematized the study of variable stars as to make it a new branch of astronomy.
Students who are interested in the subject will find the most complete information attainable in the catalogues of variable stars, published from time to time by Chandler in the 'Astronomical Journal.
Variable stars are of several classes, which, however, run into each other by gradations so slight that a sharp separation cannot always be made between them.
A classification of variable stars, based on the period of variation and the law of change, was proposed by Pickering.
It should be added that especial care will be taken not to interfere with observations of variable stars now in progress.
Variable stars may be defined as those which exhibit a varying degree of brightness at different times.
Those who have once accomplished such work are likely in the future to appreciate its value, and will often continue to do useful work in some other department of practical astronomy, if not in that of variable stars.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "variable stars" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.
