galactic plane - a misnomer

[gzotti]

From the forum, posted by Anonymous, 2014-09-01:

The great circle referred to as "galactic plane" in Stellarium (F4 > Markings) is actually the galactic equator (i.e. the equator of the galactic coordinate system). The two are different things, and as such referring to the galactic equator as the "galactic plane" constitutes an error.

If the Solar System lied exactly in the galactic plane (i.e. the central plane of the galaxy disk) then the plane of the galactic equator would be identical with the galactic plane. However, as according to existing evidence the Solar system currently lies at least ~70 ly north of the galactic plane, the galactic equator is tilted towards the actual galactic plane (between 7 and 15 minutes of arc depending on the actual exact distance of the Solar System from the galactic plane). Hence, treating the two terms as synonyms is a misnomer, and the great circle representing the galactic equator should be referred to precisely as such.

(PS I was going to attach a crude picture illustrating the matter, but the button to attach files is gone for some reason, so I uploaded it here: http://i.imgur.com/4eByKkB.png .)

I fully agree, must be renamed everywhere.

[Alexander Wolf (alexwolf)]

Diff: http://bazaar.launchpad.net/~stellarium/stellarium/trunk/revision/7033