system
Given the following post, respond as if you're commenting on Reddit:
human
How do astronomers share coordinates with each other?

Let's say an astronomer notices something worth studying out there.... How do they tell other astronomers around the world, or just record exactly where they are looking at? For instance for coordinates on Earth they'd give a lat/long and that would always be the same place.

&#x200B;

But in space, everything is in motion and therefore relative to the observer.  The earth is moving in space, and rotating as is whatever object is being studied.    So on any given day, or even time, the object being studying is not going to be in the same 'relative' space as it was yesterday, etc....

&#x200B;

So how are coordinates marked for collaboration or future study?
gpt
The sky has a similar set of coordinates as the Earth - in fact, the coordinates have the same names: latitude and longitudes. You’re correct in that the sky appears to move above us as the Earth rotates, but we astronomers have solved this by specifying a point on the sky that we define as always having coordinates (0,0). So, from the point of view of someone on Earth, the (0,0) point moves as the sky apparently moves above us.

The choice of where we’ve decided (0,0) to be is somewhat arbitrary, but if you’re curious, it’s defined as the position of the Sun on the sky at the vernal equinox (around March 21st).