University of Virginia Library

To knowe the cenyth of the arising of the sonne, this is to seyn, the partie of the orisonte in which that the sonne arisith.

Thou must first considere that the sonne arisith not alwey verrey est, but somtyme by northe the est and somtyme by south the est. Sothly the sonne arisith nevere moo verrey est in oure orisonte, but he be in the heved of Aries or Libra. Now is thin orisonte departed in 24 parties by thin azimutes in significacioun of 24 parties of the world; al be it so that shipmen rekene thilke parties in 32. Than is there no more but wayte in which azimut that thy sonne entrith at his arisyng, and take there the cenith of the arisyng of the sonne.

The manere of the divisioun of thin Astrelabie is this, I mene as in this cas: First it is divided in 4 plages principalis with the lyne that goth from est to west; and than with another lyne that goth fro south to north; than is it divided in smale parties of azymutz, as est, and est by south, where as is the first azymut above the est lyne; and so furth fro partie to partie til that thou come ageyn unto the est lyne. Thus maist thou understonde also the cenyth of eny sterre, in which partie he riseth.