Page:Description and Use of a New Celestial Planisphere.pdf/35

30 the Moon, Planets, or fixed Stars, refer to the 5th and 6th Precepts for a Rule. Example: Required to find the Moon's place in the Zodiac, on Augut 9th at noon? Look in the Nautical, or any good Ephemeris, for the Moon's Longitude, and we find it 8$s$ 19° 32', eek this place in the Ecliptic of the Planisphere, viz. 19° of Sagittary, but this is not her true place, for if you look in the next column in the Ephemeris, to the right hand, you find 5° 12' South Latitude; then bring the Longitude to the Scale of Declination, and with the compaes take 5°. 12'. Southward from this point, and et it off at right angles with the Ecliptic, with one foot in the Moon's Longitude, and the other will tand in the Moon's true place in the Zodiac; but if he had had North Latitude, then you must have taken the Latitude Northward on the Scale, and projected that ditance on the North ide of the Ecliptic, and that would be the Moon's true place in the Zodiac, where, if you make a point with a pencil, you may take the right Acenion, or Declination of the Moon, or a Planet at that time—the reason why the Scale of Declination will olve this Problem of celetial Latitude, is, the Radius of the Equinoctial and the Ecliptic being imilar, and both on a tangent cale, the error, if any, is wholly imperceptible; and note! if the place of the Moon, or a Planet be required for any certain number of hours after noon, a reduction mut be made in their Longitude and Latitude for that hour, and that Arc added to the place at noon, (if it be the Moon, or a Planet direct in motion), and that point ought in the Zodiac as before directed.