Celestia Forums

How do I find out the distances to individual stars on the SIMBAD database? Are the numbers listed somewhere I'm not seeing?

Is there a mathematical formula I need to use to figure out the distances?

Astronomers measure the distances to stars by parallax: how far nearby stars seem to shift in position as the Earth travels half-way from one side of its orbit to the other. Simbad displays this value in units of milli-arc-seconds (1/1000 arc second). If a star were to appear to shift by one second of arc, it would have a distance of one parsec (PARallax SECond), which is equivalent to about 3.26 LY. ( See http://en.wikipedia.org/wiki/Parsec )

You can use the formula

Distance (in LY) = 3.26163626 * (1000 / mas) or 3261.63626 / mas
where "mas" is the value shown by Simbad. i..e a star with a parallax of 1 mas is almost 3300 LY away.

selden wrote:Astronomers measure the distances to stars by parallax: how far nearby stars seem to shift in position as the Earth travels half-way from one side of its orbit to the other. Simbad displays this value in units of milli-arc-seconds (1/1000 arc second). If a star were to appear to shift by one second of arc, it would have a distance of one parsec (PARallax SECond), which is equivalent to about 3.26 LY. ( See http://en.wikipedia.org/wiki/Parsec )

You can use the formula

Distance (in LY) = 3.26163626 * (1000 / mas) or 3261.63626 / mas
where "mas" is the value shown by Simbad. i..e a star with a parallax of 1 mas is almost 3300 LY away.

How many digits past the decimal point is 1 parsec in light years? Meaning, is 3.26163626 the most precise number, or are there more digits past the last '6' for the absolute most precise measurement?