SECTION XXI. 315 To perform this problem you should never seek the altitude of the star when it is within an hour or two of the meridian, because at that time the altitude varies so very little. When you have gotten the altitude, then seek what is the star's hour, that is, its equatorial distance* from the meridian at that altitude, which may be done by the globe, or any quadrant, or by the analemma, just as you would seek the sun's hour if its altitude were given : After this, seek the difference between the sun's right ascension for that day and the star's right ascension, and by comparing this difference with the star's hour you will find the true hour of the night. Note, This method of operation though it be true in theory, yet it is tedious and very troblesome in practice. The most usual ways therefore of finding the hour of the night by the star's {whether they are on the meridian or not) is by making use of a large globe, or the instrument called a nocturnal, wherein the tnost remarkable stars are fixed in their proper degrees of decli- nation and right ascension : And their relation to the sun's place in the ecliptic and to his right ascension every day in the year being so obvious, makes the operation of finding the true hour very easy and pleasant. SECT. XXI.Tables of the Sun's Declination, and of the Declination and might Ascension of several remarka- ble fired Stars, together with some Account how they are to be used. THE resolution of some of the astronomical problems by geometrical operations on the analemma requires the knowledge of the true place of the sun, his right ascension or his declination at any given day of the year. But since the knowledge of his declination is of most easy and convenient use herein, and since his true place in the ecliptic as well as his right ascension may be nearly found geometrically when his declination is given, (except when near the solstices) I have not been at the pains to draw out particular tables of the sun's place, but contented myself with tables of declination for every day in the year, and tables of right ascension for every tenth day. These are sufficient for a young learner's practice in his first rudiments of astronomy. Those who make a further progress in this science and would attain greater exactness, must seek more particular tables relating to the sun in other larger treatises. Here let these few things be observed. I. These tables spew the declination of the sun each day at noon ; for it is then that the astronomer's day begins. If you * The sun or star's horizontal distance from the meridian is the azimuth : it is the equato,ial distance from the meridian which is called the sun ur star'. hour,
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