Page:Description and Use of a New Celestial Planisphere.pdf/44

39 16th at noon, viz. 5° 4', and the difference is 31'; then ay, if 24 hours, give this Arc 31', what will 7h 24m give?—Anwer, 9': which, as her Latitude is increaing, mut be added to the Latitude at noon, the 15th, 4° 33', and it makes 4° 42', the true Latitude ought; then eek the Longitude found, 1s 15° 5', in the Ecliptic, in the Planisphere, and point off the Latitude 4° 42', at right Angles thereto Northward, as per Problem 31, for noon, and this point will be the true place of the Moon at the hour and minute required, ituated in the Heavens, in the Angle between the Whale's Jaw, the Pleiades, and the Ram's North Horn; and you may now take her right Acenion and Declination with the utmot eae in an intant, by Problems 3 and 4; and, if you rectify the Planisphere for the day and hour given, you will find the Moon riing between those Stars on the East-North-East. The ame rule mut be ued with all the Planets: and note! that when any Planet is direct in motion, or increaing in Latitude, then uch increaed Arcs, in any number of hours and minutes given, must be added to their place the preceeding noon, and the um is the true place at the time required; but if the Planet be retrograde, or decreaing in Latitude, then uch Arcs of motion mut be ubtracted from their place the preceeding noon, and the remainder is the true place of the Planet required. Example, in the Planet Mercury, November 2d, 1802, at 6h 30m, P. M. his Longitude at noon, 7s 23° 49', and the third day at noon, 7s 23° 7', which is les than the econd day, and conequently he is retrograde, ubtract, and take the difference, which is 42'; then ay,