|WikiProject Astronomy||(Rated Start-class, Mid-importance)|
The distance values given are misleading. Spiral arms are not rings, and therefore statements like: Previously thought to be 13,000 light-years away, it is now thought to lie 6,400 light years from our Solar System. and The Perseus Spiral Arm, with a radius of approximately 10.7 kiloparsecs are meaningless. These values only correspond to one particular direction.
I think the last bit of the first para is missing some words. Should'nt it say "...the long bar at the center of the milky way"?JWorkman 20:59, 3 January 2013 (UTC) — Preceding unsigned comment added by James K. Workman (talk • contribs)
"It is named after its proximity to the constellation Perseus." -This is really unclear and needs both rephrasing and sourcing. The area of a constellation does not match any discrete field or pocket of 3-D space, of the Milky Way. Strictly speaking the constellations only exist on the handbook maps we make of the sky, not as any depth part of space or of the Milky Way. You can measure a distance to a given star, but not even a mean distance to a given constellation; the area on the star map that's tagged "Cygnus" or "Pisces" will contain hundreds of thousands of stars and as bodies they are unrelated.
And 98% of the individual stars we can see with the unaided eye, lie within perhaps 3.000 light years, which means nearly all of them are in the Orion Arm, where the sun itself is located. The main stars of The Perseus constellation would be Orion arm stars too. So if the name "Perseus arm" refers to anything in the constellation Perseus, it's likely to be a nebula, a radio source or something of the kind, some single object of a more distant kind.220.127.116.11 (talk) 00:20, 28 August 2013 (UTC)