When we first observe a new heavenly body (it could be a new star, asteroid, etc.,or a minor planet in our own solar system), are there any procedures set in place for establishing a system of longitudinal meridians?
Being that a prime meridian is an arbitrary concept that you can pick and establish anywhere, is a location decided based on a physical feature, or perhaps from the first points of data we gathered when making detailed observations of the heavenly bodies for the first time?
What about heavenly bodies with no easily discernible or non-stationary features (Gas Giants)? Also does the IAU regulate this process?
I have always wondered if the USSR and the US shared common reference points for locations such as on the moon.