Why don't astromers use Latitude and Longitude (instead of RA and Declination?

Question

what's the difference?

Answer 1

Lat Long is applied to a planetary body.

How would you do that in space and how would define depth or distance of the object. Also the earth is spinning would your Lat Long grid spin?

Answer 2

As the earth orbits the sun, the sun's position appears to move through the heavens. RA 0 degrees is the point at which the sun intersects the celestial equator at the ascending node. That is when the sun appears to be in front of the celestial equator during the spring equinox.

Having said all that, the main reason astronomers use this measurement is that it gives them a fixed point at which to represent stars, etc. On the celestial sphere, RA is likened to Longitude and Declination is likened to Latitude on the earth.

Answer 3

Saying that a star was at 31 degrees west longitude would imply that it was always directly above that spot on the ground. But since Earth turns, the stars are always changing which longitude they are over. So they draw a similar grid on the sky and call it by a different name and understand that they differ by how much the Earth turns, so it is measured in hours instead of degrees. Right Ascension is basically the number of house since the star passed over that longitude on Earth.

Answer 4

They use different terminology to avoid confusion. Right Ascension and Declination are effectively Longitude and Latitude projected from the centre of the Earth on to what is called the Celestial Sphere. This is the interior surface of a supposed heavenly sphere, with the centre of the Earth at its centre, which surrounds the Earth.

Answer 5

Longitude and latitude describe the static location of a place on earth, in two dimensions. Astronomy must describe a position in space in constant motion 9our motion and the subjects' motion in three dimensions. Lat. and long. do not provide the correct information to do this.

Answer 6

My son says:
with longitude and latitude you would be claiming it to be on a point on earth, you need RA and Declination to plot its point on the third plane (if you were to be even using longitude and latitude) because it also is showing where it is in "distance" to earth.

Answer 7

When you actually think about it, BOTH systems are ridiculously complicated and antiquated, being based on the ancient Babylonian system of degrees, hours, minutes, and seconds. Rather than switch one to the other, it would make more sense to switch _both_ to a decimal system, perhaps based on the radian. While we're at it, switch the way we measure time and the calendar, both of which are also based on obsolete Babylonian measurements.