Stellarium

Deep Archaeoastronomy question

Asked by Bettina Helms

I have been attempting some very deep archaeoastronomy, well pastward of the "correction" boundaries available. Specifically, I have been experimenting with the last time Polaris was the pole star, circa 23,600 BC. Since Stellarium doesn't have a BC option, I have had to use -23600, and the minus sign reverses day and night (when it doesn't scramble the time altogether) and the solstices and equinoxes.

I have tried several of the program's options to correct this, without success. I guess I just have to remember that "winter is summer, spring is fall" and vice versa. But it's annoying.

Is there a possible fix that I am overlooking, or will there be one in future versions?

Sincerely,
B. Helms

Question information

Language:
English Edit question
Status:
Solved
For:
Stellarium Edit question
Assignee:
No assignee Edit question
Solved by:
gzotti
Solved:
Last query:
Last reply:
Revision history for this message
Alexander Wolf (alexwolf) said : 		#1

Please look at screenshots for version 0.12.4:
2014 - http://astro.uni-altai.ru/~aw/stellarium/stellarium-2014.png
-23600 - http://astro.uni-altai.ru/~aw/stellarium/stellarium-23600BC.png

Which version are you using? Which operating system? Are you changed location within Stellarium and changed time zone settings in operating system?

Revision history for this message
Best gzotti (georg-zotti) said : 		#2

Note that the basic astronomical algorithms regarding planetary positions (the VSOP87 model) are likely to run into errors for times much earlier than about -6000. I absolutely expect problems with time, calendar vs. seasons will be rather funny (just use solar longitude for seasonal orientation, forget month names!), long-time trends in ecliptic obliquity are not included, lunar rotation will be completely off, and you will certainly run across many other effects of extending a mathematical/computational model waaay beyond its applicable range.

Can anybody on this planet please point us to a meaningful, well-founded, reliable long-time model that can be implemented in moderate effort in the completeness necessary for placing our objects?

Kind regards,
Georg

Revision history for this message
Bettina Helms (sk8maven) said : 		#3

Version 0.12.4
Windows 7
Doesn't matter what I do with location and time zone, the time/seasons still come out wonky. I think Georg Zotti has the right of it - the algorithms aren't accurate that far back.

The night sky seems to be more or less OK though, as far as I can tell (proper motion of Sirius is very noticeable, which is one of the things I was tracking).

Regards,
B Helms

Revision history for this message
Bettina Helms (sk8maven) said : 		#4

Thanks gzotti, that solved my question.

Revision history for this message
Patrick Wallace (ptw) said : 		#5

Georg Zotti said "Can anybody on this planet please point us to a meaningful, well-founded, reliable long-time model that can be implemented in moderate effort in the completeness necessary for placing our objects?". As far as the precession part (i.e. Earth orientation with respect to the stars ) is concerned this paper: http://www.aanda.org/articles/aa/pdf/2011/10/aa17274-11.pdf
gives algorithms to compute the equator and ecliptic poles to reasonable accuracy over +/-200 millennia.

Revision history for this message
gzotti (georg-zotti) said : 		#6

Ah, thank you, that looks interesting! It's at least one important bit of any possible change! And JPL has created DE431. Now I hope "we or someone" can fit this together correctly!
G.