2.8 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| A Treatise on the Astrolabe | 2/2 | https://en.wikipedia.org/wiki/A_Treatise_on_the_Astrolabe | reference | science, encyclopedia | 2026-05-05T16:11:41.698992+00:00 | kb-cron |
The whole of this section describes the form of an astrolabe. The astrolabe is based on a large plate ("The moder" or "mother") which is arranged to hang vertically from a thumb ring. It has "a large hool, that resceiveth in hir wombe the thin plates". The back of the astrolabe is engraved with various scales (see Skeat's sketch below). Mounted on the back is a sighting rule (Skeat's fig 3, below) "a brod rule, that hath on either end a square plate perced with certein holes". To hold it all together there is a "pyn" with a "littel wegge" (wedge) as shown below at Skeat's fig 7. Into the "womb" various thin plates can be inserted which are designed for a particular place: "compowned after the latitude of Oxenforde". These plates show the star map. Surmounting them is a "riet" or "rete" which is a pierced framework carrying the major stars shown at fig 9. Outside all is another rule, this time not with sighting holes, mounted on the common pivot, see fig 6.
=== Part 2 === Part 2 consists of around 40 propositions or descriptions of things that can be done with the astrolabe. The exact number is uncertain since of the later propositions some are of disputed or doubtful authenticity. Skeat accepts that propositions 1-40 are unambiguously genuine. Robinson generally follows Skeat's reasoning. These first 40 propositions form the canon of part 2; the propositions that follow are usually labeled "Supplementary Propositions."
== The astrolabe ==
The astrolabe was a sophisticated precision instrument. With it one could determine the date, time (when the sky was clear), the position of stars, the passage of the zodiac, latitude on the earth's surface, tides and basic surveying. Care must be taken not to dismiss the astrological aspects; as well as any mystical interpretation astrological terminology was used for what today would be recognized as astronomy. Determining when the sun entered a house (or sign) of the zodiac was a precise determination of the calendar. Skeat produced a number of sketches to accompany his edition:
The stars listed on the rim of the rete of the drawings in the Treatise are given below with their modern names:
== See also == The equatorie of the planetis by John Westwyk
== References == Footnotes
Citations
Bibliography
== External links ==
Plain-text format (with line numbering): Part 1 Part 2 from eChaucer The text of A Treatise on the Astrolabe – presented in Middle English and Modern English side-by-side. A Treatise on the Astrolabe – a verb database (language analysis, description of the astrolabe and Middle English period)