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Query about Sky Safari computation for RA, DEC of stars for ancient dates

My name is Ashirwad Tillu. I am from Mumbai, India and passionate in Astronomy. Now, retired from my long career in Information Technology and fully focusing on my above passion. I have been user of Sky Safari 5 earlier and now ver 6 Pro. 
My current interests are also in the area of Ancient historic calendars. I wish to compute the old positions of few selected stars. (How old? Say 7000 to 8000 years ago.). Sky Safari does have features to set very old dates. I have a query about the star positions shown in the App when I set very old dates. 
Now coming towards my question : Now the star positions, as we observe in the night sky, would get changed over the years, due to two factors 
- Precession in the Earth’s rotation, which will reflect on the star changing its position 
- Inherent motion of the star due to expanding universe

Does Sky safari app and its database account for both the above factors?

If yes, can I simply set the old date, and select a particular star say Arcturus, and note down its RA, DEC at that old date? 
Warm regards

1 comment

  • 0
    Bill Tschumy


    Yes, SkySafari will take into account both precession and proper motion.  In order to have proper motion taken into account, you need to enable that option in the Precession settings.  We don't leave that on by default as it can slow down the app somewhat.


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