[meteorite-list] 8000BC Big Dipper Petroglyph: Evolution of star positions

[Chris Peterson]

No apology necessary! I was just confused.

Yes, I know that some programs let you watch the evolution of asterisms. 
But nobody should be surprised if their particular star mapping program 
has short enough time limits to not allow for this.

Chris

*******************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On 9/12/2011 10:54 AM, lebofsky at lpl.arizona.edu wrote:
> Hi Chris:
>
> VERY Sorry!
>
> Just pointing out (it was sort of in the back of my mind at the time),
> that Starry Night DOES have a special routine for looking at the
> constellations and asterisms back in time. That was all!
>
> If you use the Starry Night to go back 100,000 (actually the limit is
> 99,999 years, but who is counting), the diagram that Robert Juhl showed of
> the 7 bright stars of the Big Dipper is sort of correct. But this is
> 100,000 years ago, not 8,000. I was somewhat confused by Robert's comment
> that Wu Jiacai used "different assumption." What other assumptions are
> there that would significantly change the proper motion of the start over
> this period of time (I think the program actually takes the distances to
> the stars as well as their direction of motion, so some stars get closer
> and move faster while others get farther away and appear to move slower).
>
> Again, Chris, I apologize, I only meant that the program does let you
> "look back" 100,000 years.
>
> Larry