Hipparchus
Perhaps you mean the satellite Hipparcos. It measured the position of over 100,000 stars with high precision. It also measured the position of 2.5 million stars, with lower precision.
No, stars appear the same regardless of the country you are in. The appearance of stars is determined by factors such as the atmosphere and light pollution, but these factors are not specific to any one country.
To be honest, the number of stars cannot be determined accurately. First, there are too many. Second, we can't see all of them. Some are too far away, some are too dim. We cannot see through the Milky Way, and so an unknown number of stars are hidden behind the galactic core.
The stars you see in the sky depend on the time of year and your location on Earth. The brightness of the stars, the presence of any natural or artificial light pollution, and atmospheric conditions also influence the visibility of stars in the sky.
For pure clean water at standard temperature and pressure, 850 ml has a mass of 850 grams.
...Is called a sextant, invented 1757.
He counted 850 stars. (That is what my teacher said.)
He is the father of spherical astronomy, by which the location of objects like planets and stars in the universe can be determined.
These days, an instrument called a "Sextant". Before Columbus, an "Astrolabe".
About 700-850 were saved.
No. The color is determined by the star's temperature, not location.
The tomb of Saint Peter determined the location of St. Peter's Basilica.
Your location and and the local weather conditions. The location, distance and luminosity of the stars
Stellar parallax
The temperature of a star can be determined by its color. Hotter stars appear blue/white, while cooler stars appear red.
850
The mass of a star can be determined from a binary star system, specifically by measuring the orbital motion and interaction between the two stars. This allows astronomers to apply Kepler's laws of planetary motion to calculate the masses of both stars in the system.