What does precision refers to in astronomy?
The precision is mainly related to precision in measurements of the characteristics of space bodies that are all transcendental and have no closed form like the rational number, (integer/integer).
Any space body turns relative to others and spins relative to itself.
So, the astronomers' formulas for approximating characteristics of
any space body involve explicitly, or implicitly,
Hence, it is my assertion that all (including mass) are
So, the precision is limited to the observational precision of the
data, obtained, from telescope et al, for measurements.
At present, for far-distant space bodies, the precision is about three
significant digits (3-sd), as in 3-sd age of our universe = 13.8 billion years. .