cross-staff

American  

[kraws-staf, -stahf, kros-] / ˈkrɔsˌstæf, -ˌstɑf, ˈkrɒs- /

noun

Astronomy.

cross-staffs, plural cross-staves plural

1. an instrument for measuring the angle of elevation of heavenly bodies, consisting of a calibrated staff with another shorter staff perpendicular to and sliding on it.

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Other Word Forms

Noun Inflected Forms

• cross-staffs
  plural
• cross-staves
  plural

Etymology

Origin of cross-staff

1400–50, for an earlier sense; late Middle English

Example Sentences

See Examples For:

cross-staff cross-staffs

So Tycho worked out a table of corrections for the instrument from which he could read off the correct measurement corresponding to the incorrect reading obtained by the cross-staff for any observation he made.

From "The Scientists" by John Gribbin

You can use a cross-staff, for example, to measure the angle between the horizon and the sun at midday.

From "The Invention of Science" by David Wootton

The cross-staff is a very simple instrument, a calibrated shaft along which a bar slides.

From "The Invention of Science" by David Wootton

The cross-staff is merely one of a series of instruments, such as the quadrant and the sextant, designed for measuring angles by taking sightings.

From "The Invention of Science" by David Wootton

Although the details of the instruments he used are not crucial to my story, it is worth mentioning one, called a cross-staff or radius, which Tycho had made for him early in 1564.

From "The Scientists" by John Gribbin

Got Gordon to make a dozen cross-staffs and started for it to take levels.

From The Narrative of Gordon Sellar Who Emigrated to Canada in 1825 by Sellar, Gordon