View Single Post
  #3  
Old November 14th 17, 11:36 PM posted to sci.astro.amateur
Mike Collins[_4_]
external usenet poster
 
Posts: 2,824
Default Venus and Jupiter

Gerald Kelleher wrote:
http://wwwcdn.skyandtelescope.com/wp...ember-2017.jpg

Saw this through the break in the clouds and it was as lovely as could
be. Venus is moving in behind the central Sun and will transition to an
twilight appearance once more whereas Jupiter will move back through the night.

http://www.popastro.com/images/plane...ary%202012.jpg

While it is wonderful to predict the astronomical events like the sight
of Venus and Jupiter in close proximity using a rotating celestial
sphere, don't try to model the motions of the Earth, the other planets
and solar system structure on that RA/Dec framework -

https://www.youtube.com/watch?v=5HAQk3dhsa0

So much more to enjoy once the future software program emerges that
substracts the daily rotation of the planet and allows the
planets,including our own, to travel freely in context of our motion and
that of the central Sun along with the motions of the satellites of each
planet around their parent.




Contrary to your belief RA and DEC are not used to calculate the positions
of the planets. The 6 Keplerian orbital elements are used for this.

https://en.wikipedia.org/wiki/Orbital_elements

In my 1980s software RA and DEC (and altitude and azimuth) were only
calculated once the relative positions of the planets in their orbits had
been calculated.
I have no reason to believe that modern software is different.