To knowe every tyme of the day by light of the sonne; and
every tyme of the nyght by the sterres fixe; and eke to knowe by
nyght or by day the degre of eny signe that ascendith on the est
orisonte, which that is clepid comounly the ascendent, or ellis
horoscopum.
Tak the altitude of the sonne whan the list, as I have seid,
and set the degre of the sonne, in caas that it be beforn the
myddel of the day,
among thyn almykanteras on the est
syde of thin Astrelabie; and if it be after the myddel of the
day, set the degre of thy sonne upon the west syde. Tak this
manere of settyng for a general rule, ones for evere. And whan
thou hast set the degre of thy sonne upon as many almykanteras
of height as was the altitude of the sonne taken by thy rule, ley
over thi label upon the degre of the sonne; and than wol the
point of thi labell sitte in the bordure upon the verrey tyde of
the day.
Ensample as thus: The yeer of oure lord 1391, the 12 day of
March, I wolde knowe the tyde of the day. I tok the altitude of
my sonne, and fond that it was 25 degrees and 30 minutes of
height in the bordure on the bak side. Tho turned I myn
Astrelabye, and by cause that it was before mydday, I turned
my riet and sette the degre of the sonne, that is to seyn the
firste degre of Aries, on the right side of myn Astrelabye upon
25 degrees and 30 mynutes of height among myn almykanteras. Tho
leide I my label upon the degre of my sonne, and fond the point
of my label in the bordure upon a capital lettre that is clepid
an X. Tho rekned I alle the capitale lettres fro the lyne of
mydnight unto this forseide lettre X, and fond that it was 9 of
the clokke of the day. Tho loked I doun upon myn est orizonte,
and fond there the 20 degre of Geminis ascendyng, which that I
tok for myn ascendent. And in this wise had I the experience for
evermo in which manere I shulde knowe the tyde of the day and eke
myn ascendent.
Tho wolde I wite the same nyght folewyng the houre of the
nyght, and wroughte in this wise: Among an heep of sterres
fixe it liked me for to take the altitude of the faire white
sterre that is clepid Alhabor, and fond hir sittyng on the west
side of the lyne of midday, 12 degrees of heighte taken by my
rewle on the bak side. Tho sette I the centre of this Alhabor
upon 12 degrees among myn almykanteras upon the west side, by
cause that she was founde on the west side. Tho leyde I my label
over the degre of the sonne, that was discendid under the west
orisounte, and rekned all the lettres capitals fro the lyne of
midday unto the point of my label in the bordure, and fond that
it was passed 9 of the clokke the space of 10 degrees. Tho lokid
I doun upon myn est orisounte, and fond there 10 degrees of
Scorpius ascendyng, whom I tok for myn ascendent. And thus lerned
I to knowe onys for ever in which manere I shuld come to the
houre of the nyght, and to myn ascendent, as verrely as may be
taken by so smal an instrument.
But natheles this rule in generall wol I warne the for
evere: Ne make the nevere bold to have take a just ascendent by thin
Astrelabie, or elles to have set justly a clokke, whan eny
celestial body by which that thou wenyst governe thilke thinges
be nigh the south lyne. For trust wel, whan the sonne is nygh the
meridional lyne, the degre of the sonne renneth so longe
consentrik upon the almykanteras that sothly thou shalt erre fro
the just ascendent. The same conclusioun sey I by the centre of
eny sterre fix by nyght. And more over, by experience I wot wel
that in oure orisounte, from xi of the clokke unto oon of the
clokke, in taking of a just ascendent in a portatif Astrelabie
it is to hard to knowe—I mene from xi of the clokke before
the houre of noon til oon of the clokke next folewyng.
