CHAP. 1. To find the Suns greatest Declination, and the Poles Elevation.
THe Declination of a Planet, or other Star is his distance from the Aequator, and as he declines from thence either Northward or Southward, so is his declination nominated North or South. And because that all the Planets (the Sun onely excepted) do move sometimes in and sometimes out of the Ecliptick besides there declination North or South from the Aequa∣tor, they have also latitude North or South from the Ecliptique, while the Planets keep in the ecliptique, one rule will serve to find their Declinati∣on, as well as the Declination, of the Sun, but if they have either North or South latitude, there must another rule be given, in both which rules the greatest Declination of the Sun is supposed to be known; and first there∣fore we will shew how, that may be found instrumentally, and then com∣pute the Declination of a Planet or other Star, with latitude or without.
For the finding the Suns greatest Declination, you must by a Quadrant or other Instrument, take his greatest and his least Meridian altitude; the difference between which altitudes is the distance of the Tropiques, and half the distance of the Tropiques, is the quantity of the Suns great De∣clination, as by the following Figure it doth appear. In which A Z B N represents the Meridian, E F the Eq••inoctial, ♋ ♑ the Zodiack, the