AN ELEMENTARY INTRODUCTION TO THE NAUTICAL ALMANAC, AND ASTRONOMICAL EPHEMERIS; CONTAINING FAMILIAR EXPLANATIONS OF ALL THE TECHNICAL WORDS EPITOME OF ASTRONOMY WITH SIXTY ENGRAVED DIAGRAMS. BY G. P. PAYNE, OPTICIAN, LIVERPOOL. LONDON: CHARLES WILSON, LEADENHALL ST. LIVERPOOL: MELLING & PAYNE, SOUTH CASTLE ST. 1842. 1253. PREFACE. THE scheme of the following pages is to afford instruction without the aid of any other work than the "Nautical Almanac, and Astronomical Ephemeris," to which it is professed they are an Introduction. Writers on Elementary Astronomy generally either reserve the information most eagerly sought by the curious, or detail it on the supposition that the reader is a mathematician. Undoubtedly no great progress can be made in Astronomy without the aid of the mathematics, but there may be a medium between a perfect acquaintance with these abstruse studies and a sufficient knowledge to make astronomical data easy of comprehension. The Author, therefore, in pursuance of his plan has, he believes, familiarised and introduced as many scientific explanations as may enable any student to comprehend the facts and complicated theories of the Celestial Phenomena. It will be immediately evident to the scientific reader that any attempt at such explanations beyond an outline would not be consistent with the scope of so small a work as the present. The alphabetical arrangement has been adopted for the convenience of reference, and care has been taken to give in every article the words to which the student must refer to complete his information on any one subject. EPITOME OF ASTRONOMY. O The Sun. ASTRONOMY may be defined as the science which teaches the order, motions, distances, magnitude, eclipses and appearances of the heavenly bodies, and their relation to the Earth. The study of this science consists of systematic observations of the sun moon, planets and fixed stars; and to assist these observations there are books and tables of general calculations, maps which delineate the apparent places of the starry host; and the celestial globe, on which we see the stars, not as they appear in the heavens, but reversed for the purpose of working problems. The stars on the celestial globe would present a picture of nature if the globe were hollow, the stars pierced through the shell, and we were to view these apertures from the centre instead of the circumference. The symbols and abbreviations used in Astronomy are the following:SIGNS of the ZODIAC. Hours of да o Conjunction. Trine. Right Ascension. 0 r Aries. Celestial Longi tude. 0° Descending Node. III. tor The Earth. S. South. IV. N II. II Gemini. Leo. 120 R.A. Right Ascension. Dec. Declination. Long. Longitude. Lat. Latitude. η Greek characters to denote the magnitude of fixed stars in any particular constellation: a Alpha, First magnitude; ẞ Beta, Second; y Gamma, Third; & Delta Fourth; € Epsilon, Fifth; Zeta, Sixth; ʼn Eta, Seventh; 9 Theta, Eighth; Iota, Ninth; « Kappa Tenth. These characters are sufficient to distinguish the principal fixed stars, but the whole of the Greek alphabet is used,and, when exhausted, the Italian and Roman characters, and the common numerals are employed. When a Greek character and a numeral are both used they denote that there is more than one star of the same magnitude in the constellation; as a2 Geminorum, (Castor,) the star Pollux being a1 Geminorum. a, Alpha, also signifies Ascension, and S, Delta, Declination. |