"Practical Talks by an Astronomer" by Harold Jacoby. Published by Good Press. Good Press publishes a wide range of titles that encompasses every genre. From well-known classics & literary fiction and non-fiction to forgotten−or yet undiscovered gems−of world literature, we issue the books that need to be read. Each Good Press edition has been meticulously edited and formatted to boost readability for all e-readers and devices. Our goal is to produce eBooks that are user-friendly and accessible to everyone in a high-quality digital format.
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Harold Jacoby. Practical Talks by an Astronomer
Practical Talks by an Astronomer
Table of Contents
PREFACE
ILLUSTRATIONS
NAVIGATION AT SEA
THE PLEIADES
THE POLE-STAR
NEBULÆ
TEMPORARY STARS
GALILEO
THE PLANET OF 1898
HOW TO MAKE A SUN-DIAL[A]
Footnote
PHOTOGRAPHY IN ASTRONOMY
TIME STANDARDS OF THE WORLD
MOTIONS OF THE EARTH'S POLE
SATURN'S RINGS
THE HELIOMETER
OCCULTATIONS
MOUNTING GREAT TELESCOPES
THE ASTRONOMER'S POLE
THE MOON HOAX
THE SUN'S DESTINATION
INDEX
Отрывок из книги
Harold Jacoby
Published by Good Press, 2021
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This same gravitational attraction must be at work among the Pleiades. They, too, like ourselves, must have bounds and orbits set and interwoven, revolutions and gyrations far more complex than the solar system knows. The visual discovery of such motion of rotation among the Pleiades may be called one of the pressing problems of astronomy to-day. We feel sure that the time is ripe, and that the discovery is actually being made at the present moment: for a generation of men is not too great a period to call a moment, when we have to deal with cosmic time.
It is indeed the lack of observations extending through sufficient centuries that stays our hand from grasping the coveted result. The Pleiades are so far from us that we cannot be sure of changes among them. Magnitudes are always relative. It matters not how large the actual movements may be; if they are extremely small in comparison with our distance, they must shrink to nothingness in our eyes. Trembling on the verge of invisibility, elusive, they are in that borderland where science as yet but feels her way, though certain that the way is there.
