- 行业: Earth science
- Number of terms: 93452
- Number of blossaries: 0
- Company Profile:
Founded in 1941, the American Congress on Surveying and Mapping (ACSM) is an international association representing the interests of professionals in surveying, mapping and communicating spatial data relating to the Earth's surface. Today, ACSM's members include more than 7,000 surveyors, ...
A telescope having a spherical primary mirror and a specially figured correcting plate, and a special mounting for tracking artificial satellites. The optical system was designed by J. A. Baker and the mounting by J. Nunn. It is a variation of the Schmidt type, with the focal surface having a toroidal shape instead of a spherical shape. The correcting plate contains three elements, giving an aperture of 50 cm and a focal length of 50 cm. The field of view is 5° by 30°. The mounting is of the alt azimuth type but allows tracking in right ascension and declination also. The optical system and mounting together allow a 12 th magnitude star to be photo-graphed when the direction of pointing is fixed, or allow an object of 8. 5 magnitude moving at 0. 1° per second to be photographed when the telescope is following the motion.
Industry:Earth science
Touching, as distinguished from being merely close to or adjacent. adjoining and abutting are at present often used as if they were synonymous. However, it is recommended that the old distinction be retained where possible. Two parcels adjoin if they have a common side; they abut if they have a common end. (2) Close to. This usage is improper but, fortunately, rare.
Industry:Earth science
A condition equation expressing the relationship between the fixed azimuths of two lines connected by traverse or triangulation. When traverse or triangulation connects two lines whose azimuths are fixed by direct observations or by previous surveys, an azimuth equation is used to make the azimuth of either line (as computed through the adjusted survey) from the other line agree with its azimuth as previously fixed.
Industry:Earth science
A measure of the ability of the eye to separate details in viewing an object, and taken to be the reciprocal of the smallest angular separation, in minutes of arc, of two lines which can be seen to be separate.
Industry:Earth science
A code (1) which uses five binary digits to represent one character.
Industry:Earth science
A vertical-control datum in Australia, based on a defined geoidal height of 6 meters at Johnston Geodetic Station.
Industry:Earth science
A nearly horizontal portion of the beach, formed by the material left by the waves. Some beaches have no beach berms, while others may have several.
Industry:Earth science
(1) In general, an unmistakable and pronounced indentation of a coast. According to the Geneva Convention of 1958, a bay is: a well marked indentation whose penetration is in such proportion to the width of its mouth as to contain landlocked waters and constitute more than a mere indentation of the coast. An indentation should not be regarded as a bay, however, unless its area is as large as or larger than that of a semicircle whose diameter is a line drawn across the mouth (i.e., from headland to headland, or from extremity to extremity) of that indentation. For the purposes of measurement, the area of an indentation is that lying between the low water mark around the shore of the indentation and a line joining the low water marks at its natural entrance points.
(2) The body of water contained within a bay as defined in (1) above.
Industry:Earth science
The line drawn through the optical center and centers of curvature of the lenses of a telescope.
Industry:Earth science
