A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Date: 2016 Sep 26, 23:40 -0700
Sure, any wobble of the Earth axis affects SHA and Dec, but the question was about relative star positions. These cannot change by a change of reference frame. Other than aberration and parallaxe, which Frank already covered, only proper motion of the stars will affect their relative positions. The effect can actually be greater than that of parallax, but as far as I am aware, it concerns only one navigational star: Alpha Centauri. An almanac that is 20 years old will show a position that is wrong by a little more than a minute of arc. That's how fast this star moves. Anyway, for navigation I never work to that level of precision, only for my horoscopes it becomes important.