Originally from ticket #25456.

I am interested in researching planetary positions long time ago, e.g. BC (> 2000 years ago). I know that planetary positions are accurate depending on SkySafari Version (Pro to better than 0.1''), but I guess this number is only valid for current dates around year 2016 (with some temporal range). Is there more info on the longterm accuracy available? I have the Mac OS and the Android version of SNPP.

Searching the SCC website and on the internet did not bring any more evidence. Any info would be appreciated.

Keiron Smith replies:

HI Lima,

Are you asking about the accuracy of planetary projections in Starry Night or SkySafari? You have referenced both programs in your query. Thanks!

Keiron Smith
Starry Night & Sky Safari Software Support Team

Ticket update:

Hi Keiron,  
thanks for the quick reply.  I meant Sky Safary Pro (Mac Version).  Thanks in advance 
Laura 

Von Samsung-Tablet gesendet

Tim DeBenedictis replies:

Planetary positions should be good to a few arcseconds for times within 10,000 years of the present, and to better than an arcsecond for times from 1600 to 2100 AD.

-Tim DeBenedictis
SkySafari / Simulation Curriculum