The Jacob's Staff - AstroMedia
Columbus used this ingenious medieval measuring instrument to determine the heights and angular distances of stars and landmarks.
Predecessor of the sextant
The Jacob's staff served reliably for a long time before it was superseded by the mirror sextant in the 18th century. The historically accurate, fully functional cardboard replica has a longitudinal rod with scales that can be read to the minute and 3 transverse rods for the ranges from 8°, 15° and 29° to 45° in each case.
How to measure
Put one crossbar on the longitudinal bar and place its flat end under the eye on the cheekbone. Push the crossbar back and forth until it fits exactly between the two points. If the angle is too small or too large, take another crossbar. The angle can be measured at the front of the crossbar, where the longitudinal bar enters it. Each crossbar has its own scale there.
For teachers and pupils
Jacob's staff is easy to build and is an excellent material for teaching in secondary schools. Like all other astro materials, it can of course also be used for other group and project work on astronomy and physics.
You can find a detailed illustrated construction report here.
| Aspiration scale: | Easy |
|---|---|
| Time Line: | 1,0 Hour |
Cut-out cardboard sheet, printed
for assembly, 3 x DIN A4
with detailed assembly instructions
Size of the finished article: approx. 57 x 28 cm
Der Jakobsstab - Deutsch€2.90
€2.76
€2.61
€2.47