- The
backstaff is a
navigational instrument that was used to
measure the
altitude of a
celestial body, in
particular the Sun or Moon. When
observing the...
- the cross-staff
could not
compete with the
backstaff in many countries. In
terms of handling, the
backstaff was
found to be more easy to use. However,...
- pear tree or boxwood, with an arch of 15° to 30°, it is an
example of a
backstaff. The sun
casts that
shadow of a vane (B in the
adjacent image) on a horizon...
- Also,
unlike the
backstaff, the ****tant
allows direct observations of stars. This
permits the use of the ****tant at
night when a
backstaff is
difficult to...
- back
observation quadrant. This
instrument was used in the
manner of a
backstaff to
measure the
elevation of the sun by
observing the
position of a shadow...
- maps.
Seventeenth century marine navigation and
cartography used the "
backstaff" which, in this area, was
accurate to one
degree of longitude, or around...
-
angle of the sun or a star
above the
horizon with an
instrument such as a
backstaff or quadrant.
Longitude was more
difficult to
measure accurately because...
- 1496 by the
Castilian Jew
Abraham Zacut, then
exiled in Portugal. The
backstaff,
which measures the
length of a shadow, was used from the 16th century...
-
devices based on the same
principle were used,
notably the cross-staff and
backstaff. The
kamal is
still a tool
recommended for use in sea kayaking. In such...
- by
Michelborne on his
return to
England in 1606. His
invention of the
backstaff and
double quadrant (called the
Davis quadrant after him)
remained po****r...
