You're literally so ignorant you didn't know sextants are used

specifically, for finding spherical longitude/latitude coordinates.

The stars are used to determine longitude and latitude, with one.

Are we all gonna have to tell you this again tomorrow??

As mentally ill as you act, I'm betting we will.

"Sextant - Principle, Types, and Uses"

"The Nautical sextant, also called as the Vernier sextant or Marine sextant,

is an instrument mainly used, TO DETERMINE LONGITUDE and LATITUDE,"

by measuring angles between two objects."

https://theconstructor.org/surveying/sextant-types-uses/33990/

Britannica Encyclopedia:

"Sextant: An instrument for determining the angle between the horizon

and a celestial body such as the Sun, the Moon, or a star,

used in celestial navigation, TO DETERMINE LATITUDE and LONGITUDE.''

https://www.britannica.com/technology/sextant-instrument

And no, a sextant doesn't only work on a flat object it uses the horizon on Earth.

SEXTANTS ARE DESIGNED to be USED

TO FIND LONGITUDE and LATITUDE.

Which is why they have build-in error of a couple of kilometers.

Every word you wrote

was UTTERLY wrong.

"Sextant"

"The sextant was designed to find longitude by measuring the angular distance between the moon and a nearby star."

"It was also used on land and to find latitude, at sea."

https://amhistory.si.edu/navigation/type.cfm?typeid=6

Utterly wrong answer.

People have been finding longitude and latitude for more than THREE HUNDRED YEARS,

using sextants.

https://duckduckgo.com/?q=HISTORY+of+longituded+and+latitutde&ia=web

You literally couldn't find a WAY

to be MORE wrong.

https://sultanaeducation.org/wp-content/uploads/2014/06/Navigation-latitude-and-longitude.pdf

"Navigation: Latitude and Longitude"

"Sextants and Chronometers Help Sailors Find Their Position at Sea."