Pole star, precession & antiquity

[MrCrowley]

Hi all,

I was searching the web for information about Polaris in the antiquity. I thought that I would not find any references, since from what I know the precession makes that Polaris was not the pole star in antiquity, for example in the Egypt of the first dynasties.

I have found that there are references to Polaris in many cultures, for example ancient China, India, Arabic cultures, the Norse, etc. Why does it has so much importance in these cultures, since back then it was further away from the pole? Is it because, even beign farther, it was still the closest star to the pole?

I would like to know since when is Polaris the pole star? And when did we name it Polaris? I think the name comes from ancient Greece, but back then, how far from the pole was Polaris? And in the 1500's, at the beginning of the European exploration of America, how far from the pole was Polaris?

Sorry to bother you with these many historical questions. Thank you in advance for your help!

[clop]

Hi all,

I was searching the web for information about Polaris in the antiquity. I thought that I would not find any references, since from what I know the precession makes that Polaris was not the pole star in antiquity, for example in the Egypt of the first dynasties.

I have found that there are references to Polaris in many cultures, for example ancient China, India, Arabic cultures, the Norse, etc. Why does it has so much importance in these cultures, since back then it was further away from the pole? Is it because, even beign farther, it was still the closest star to the pole?

I would like to know since when is Polaris the pole star? And when did we name it Polaris? I think the name comes from ancient Greece, but back then, how far from the pole was Polaris? And in the 1500's, at the beginning of the European exploration of America, how far from the pole was Polaris?

Sorry to bother you with these many historical questions. Thank you in advance for your help!

Hmm well according to my SkyMap software, Polaris is currently

RA: 02h 37m 51.24s
Dec: +89° 17' 20.5"

so it is less than 1 degree from the pole.

On this day in 1500, Polaris was as follows

RA: 00h 15m 06.10s
Dec: +86° 34' 46.7"

over 3 degrees from the pole, but still the closest bright star to it.

And on this day in 500BC, Polaris was as follows

RA: 23h 00m 25.41s
Dec: +75° 30' 31.5"

almost 15 degrees from the pole.

In those days the closest bright star to the pole was

Proper name: Kochab
Bayer letter: beta Ursae Minoris
Flamsteed number: 7 Ursae Minoris
Magnitude: 2.20

RA: 16h 42m 40.82s
Dec: +82° 56' 08.9"

which was still a far way away.

You have to go back a long long way to see a significant change.

Right back in 3000BC the pole star was

Constellation: Draco
Proper name: Thuban
Bayer letter: alpha Draconis
Flamsteed number: 11 Draconis
Magnitude: 3.60

RA: 23h 36m 27.67s
Dec: +88° 50' 53.9"

and even further back, in 10000BC, the pole wasn't far from Vega!


clop

[grant hutchison]

The Greeks certainly had a pole star (or stars) they referred to as Polos, and the Romans had a star they called Polus: but whether that was the same star from era to era is anyone's guess, since we know only that it was a name for a bright star that appeared relatively fixed in the northern sky. So in the first millennium BCE, when the pole was between Polaris and Kochab, the name might have been applied to either or both. Certainly the Greeks were well aware that their Polos wasn't fixed in the sky: both Pytheas in 320BCE and Hipparchos in 150BCE commented upon this, according to Richard Hinkley Allen's Star Names: Their Lore and Meaning.
By the standards of navigation of the day, a pole star that was out of place by a mere ten degrees would still be quite useful.

Grant Hutchison

[MrCrowley]

Thanks for the information.

[ToSeek]

Vega gets its turn as the pole star, which would be really cool.

[grant hutchison]

The shift from Kochab to Polaris as pole star occurred around 400CE, when they were both about ten degrees from the pole.
Shakespeare put the words "I am constant as the northern star ..." into Julius Caesar's mouth, so it's ironic to realize that in Caesar's time there really wasn't a constant northern star, with both Kochab and Polaris moving through wide circles around the pole: 16 degrees across for Kochab, and 24 degrees for Polaris.

Grant Hutchison

[Ken G]

Maybe Shakespeare knew more astronomy than we give him credit for... look what happened to Julius!

[Romanus]

Precession is easy to see over the course of a lifetime; Polaris is nearly a degree closer to the NCP now than it was a century ago. Hence the updating of catalog epochs every 50 years or so.

[clop]

Precession is easy to see over the course of a lifetime; Polaris is nearly a degree closer to the NCP now than it was a century ago. Hence the updating of catalog epochs every 50 years or so.

You can say that again.

clop