Editing Gaussian gravitational constant (section)

==Other definitions==
{{see|Gravitational constant}}
The value of Gauss's constant, exactly as he derived it, had been used since Gauss's time because it was held to be a fundamental constant, as described above. The [[solar mass]], [[Solar time#Mean solar time|mean solar day]] and [[sidereal year]] with which Gauss defined his constant are all slowly changing in value. If modern{{clarify|date=June 2018}} values were inserted into the defining equation, a value of {{val|0.01720209789}} would result.{{dubious|date=June 2018}}<ref name="Danby88">{{cite book  | last = Danby | first = J. M. A. | title = Fundamentals of Celestial Mechanics | publisher = Willmann-Bell | location = Richmond, VA | year = 1988 | isbn=0-943396-20-4|page=146}}</ref> <!--this is at best outdated (1988), and obsolete at least since the 2012 redefinition of the AU-->

It is also possible to set the gravitational constant, the mass of the Sun, and the astronomical unit to 1. This defines a unit of time with which the period of the resulting orbit is equal to {{math|2π}}. These are often called ''canonical units''.<ref name="Danby88"/>