Review of galactic constants

Whereas the 1964 IAU standard values of the constants $R_0=10\enspace \text{kpc},\enspace \theta_0=250\enspace\text {km}\enspace \text s^{-1},\enspace A=15\enspace \text {km}\enspace \text s^{-1}\enspace \text {kpc}^{-1}, \enspace \text {and}\enspace B=-10\enspace \text {km}\enspace \text s^{-1}\enspace \text {kpc}^{-1}$, differ from those currently considered best, the errors of current determinations are still rather large. Although the means of recent determinations lead to a fairly consistent set of values for the four main constants, the agreement may be largely coincidental. However, a case can be made for agreeing on the pair of standard values $R_0=8.5\enspace \text {kpc} \enspace \text {and}\enspace \theta_0=220\enspace \text {km}\enspace \text s^{-1}$. On the basis of this review these were adopted by resolution of IAU Commission 33 on 1985 November 21 at Delhi.