The Telescope

Few things are more generally disappointing than one’s first glimpse of the Heavens through a telescope. The novice is fed up with maps of Mars as a great disc full of intricate...

A word at the start concerning the choice and purchase of telescopes. The question of refractors vs. reflectors has been already considered. The outcome of the case depends on h...

Aside from the ordinary equipment of oculars various accessories form an important part of the observer’s equipment, their number and character depending on the instrument in us...

In the credulous twaddle of an essay on the Lost Arts one may generally find the telescope ascribed to far antiquity. In place of evidence there is vague allusion of classical t...

A steady and convenient mounting is just as necessary to the successful use of the telescope as is a good objective. No satisfactory observations for any purpose can be made wit...

The path of the rays through an ordinary telescope has been shown in Fig. 5. In principle all the rays from a point in the distant object should unite precisely in a correspondi...

The chief link between the old and the new, in instrumental as well as observational astronomy, was Sir William Herschel (1738-1822). In the first place he carried the figuring...

In regard to getting a telescope into action and giving it suitable protection, two entirely different situations present themselves. The first relates to portable instruments o...

Glass, one of the most remarkable and useful products of man’s devising, had an origin now quite lost in the mists of antiquity. It dates back certainly near a thousand years be...

The eyepiece of a telescope is merely an instrument for magnifying the image produced by the objective or mirror. If one looks through a telescope without its eyepiece, drawing...

The hand telescope finds comparatively little use in observing celestial bodies. It is usually quite too small for any except very limited applications, and cannot be given suff...

Every optical expert has his own favorite methods of working out the figure. If there is a hollow zone the whole surface must be worked down to its level by repolishing; if, on...