[bibanez]

Every object in the sky has precise absolute coordinates. As far as I know, there is not a comprehensive database of all sky objects but several databases from different sky surveys that map only a part of the sky. To check if the object is new, you just look up the coordinates in a program that aggregates all the different databases, like Simbad (https://simbad.cds.unistra.fr)

[sb8244]

Does the current location of the earth affect that coordinate system at all, or i is negligible due to distances?

[jfengel]

They use a Galactic Coordinate System, which is actually centered on the Sun, in the plane of the galaxy. (The sun does revolve around the galaxy, but with a period of millions of years it doesn't make a measurable difference.)

https://en.m.wikipedia.org/wiki/Galactic_coordinate_system

It can easily be transformed into telescope pointing directions with the input of location on the planet, time of year and time of day.

[euroderf]

IIRC the Earth has made 2.5 orbits about the galactic center since its [the Earth's] formation.

[dwaltrip]

The period is ~250 million years. Quite the journey! :)

[BurningFrog]

Up to ~300 light years away this effect can be used to estimate the distance to a star.

For other galaxies the effect is very much indistinguishable from 0.

https://lco.global/spacebook/distance/parallax-and-distance-...