<p>What you're asking for in the comments, on ancient predictions, that's a tricky subject.  You're basically talking about proper motion and Edmund Halley was the first person to observe it.   He recognized that 3 stars were about 1/2 a degree from where they were observed 1,850 years earlier.</p>

<p><a href="https://en.wikipedia.org/wiki/Proper_motion#History" rel="nofollow noreferrer">Source</a>.</p>

<p>1/2 of 1 degree in the night sky is larger than you might think.  It's about the diameter of the full moon, but 1,850 years is a long time.   That's why it went unnoticed until Halley took a closer look at the ancient star charts. </p>

<p>It's noted in the Wikipedia article that the ancient Greeks suspected proper motion happened but they were unable to observe it and nobody can make a decent prediction based on something that changes so slowly they are unable to observe it.</p>

<p>With today's observation methods, it's just a matter of running a computer simulation to see what the constellations will look like 100 years from now (virtually unchanged) or 10,000 years from now (some of them would begin to be visibly skewed but likely still recognizable).   </p>

<p>Every star has it's own proper motion, so each constellation would undergo it's own rate of change.</p>

CC BY-SA 3.0
2017-10-25T07:23:01.953Z
2017-10-26T11:28:49.137Z
2017-10-26T11:28:49.137Z
userLTK
<p>No, there is no possible way that humans from any known civilization in the first century AD would have been able to extrapolate current constellation positions.</p>

<p>Prior to the work of <a href="https://en.wikipedia.org/wiki/Johannes_Kepler" rel="nofollow noreferrer">Johannes Kepler</a> and <a href="https://en.wikipedia.org/wiki/Isaac_Newton" rel="nofollow noreferrer">Isaac Newton</a>, humans did not have sufficient knowledge of the basic principles of celestial movement to have any kind of basis for making such calculations.</p>

<p>Second, even if they had the basic principles, they would also have needed much more accurate and detailed information about the makeup of the Milky Way galaxy. The information currently available, that goes into the NASA models, is the product of a great many man-years invested in both observations and analysis of those observations.</p>

<p>Third, even if they had the basic principles and the necessary details with which to create a proper model, they lacked the computing power necessary to actually run the model - computation of that time being limited to pencil and paper (or perhaps an abacus).</p>

CC BY-SA 3.0
2017-10-26T11:25:05.737Z
Would you feel that software models that "turn back the clock" are accurate?
Doug Kimzey
CC BY-SA 3.0
2017-10-26T15:34:01.557Z
@DougKimzey It is as accurate as we can currently make it. Not being an actual astronomer, I don't know what the limitations of our current understanding are.
Donald.McLean
CC BY-SA 3.0
2017-09-23T03:14:57.860Z
2017-09-23T03:14:57.860Z
Donald.McLean
<p>Would someone know of a good reference on the oldest known predictions of constellation positions?  </p>

<p>How far ahead could accurate positions be predicted? </p>

<p>For example, could current constellation positions be accurately predicted between A.D. 69 to A.D. 86?</p>

CC BY-SA 3.0
2017-09-22T13:42:30.607Z
How about the specific alignments of constellations with planets and stars?
Doug Kimzey
CC BY-SA 3.0
2017-09-22T14:16:15.217Z
I'm very curious if there are any records from 2000 years ago of accurate predictions of current planet and star positions and if so; what is known of their methods?
Doug Kimzey
CC BY-SA 3.0
2017-09-22T14:16:21.767Z
Stellarium (free program) has back-predictions that are accurate up to 2000 B.C. I've confirmed that myself by checking old Babylonian data of eclipses and stellar occultations around 500 BC. If you're asking the other direction, no 2000 years ago nobody could have predicted any planetary position.
AtmosphericPrisonEscape
CC BY-SA 3.0
2017-09-22T14:17:55.650Z
People didn't understand gravity until Newton came along. Only after his work was published could predictions be made.
AtmosphericPrisonEscape
CC BY-SA 3.0
2017-09-22T14:19:04.900Z
Are there any records of forward predictions made in the past that accurately predict the positions of stars and planets in the 20th and 21st century?  If so, what do we know of their methods?
Doug Kimzey
CC BY-SA 3.0
2017-09-22T14:28:25.200Z
AtmosphericPrisonEscape - this is a good point, but were there any tools available in ancient times that we would consider as empirical today that might be employed to yield accurate long term predictions?
Doug Kimzey
CC BY-SA 3.0
2017-09-22T14:36:40.070Z
Actually, I am most interested in any predictions made in ancient times about the present day positions of stars, constellations and planets.  If such predictions exist and are accurate; given the absence of knowledge of gravitational forces, what methods were used to make the predictions.
Doug Kimzey
CC BY-SA 3.0
2017-09-22T15:24:26.453Z
There is a huge difference between asking about "constellation positions" which change very slowly due to precession. Star positions, some of which change very slowly due to proper motion and "planet positions" which change very rapidly. Its not clear what you mean, since the comments contradict the body of the question. The ancients could have made a good estimate of constellation positions, there model of the planets would be good for a few decades, but not for a few millenia
James K
CC BY-SA 3.0
2017-09-22T17:03:33.507Z
Very well put - would anyone know of any references to historical attempts to predict the slowly changing constellation positions and the more rapidly changing stars and planets?
Doug Kimzey
CC BY-SA 3.0
2017-09-22T20:22:37.323Z
I'd have said ancient astrologers were the first to attempt to predict the motion of constellations in the sky.  I'd suggest starting looking at that subject (which I'm not at all familiar with).
StephenG - Help Ukraine
<history><constellations>
What is the oldest known prediction of constellation positions?
Doug Kimzey
# What is the oldest known prediction of constellation positions?

(Asked by: username_0 on 2017-09-22)

Would someone know of a good reference on the oldest known predictions of constellation positions?

How far ahead could accurate positions be predicted?

For example, could current constellation positions be accurately predicted between A.D. 69 to A.D. 86?

**Tags:** history, constellations
> **Comments:**
> **username_0**: How about the specific alignments of constellations with planets and stars?  
> **username_0**: I'm very curious if there are any records from 2000 years ago of accurate predictions of current planet and star positions and if so; what is known of their methods?  
> **username_1**: Stellarium (free program) has back-predictions that are accurate up to 2000 B.C. I've confirmed that myself by checking old Babylonian data of eclipses and stellar occultations around 500 BC. If you're asking the other direction, no 2000 years ago nobody could have predicted any planetary position.  
> **username_1**: People didn't understand gravity until Newton came along. Only after his work was published could predictions be made.  
> **username_0**: Are there any records of forward predictions made in the past that accurately predict the positions of stars and planets in the 20th and 21st century?  If so, what do we know of their methods?  
> **username_0**: AtmosphericPrisonEscape - this is a good point, but were there any tools available in ancient times that we would consider as empirical today that might be employed to yield accurate long term predictions?  
> **username_0**: Actually, I am most interested in any predictions made in ancient times about the present day positions of stars, constellations and planets.  If such predictions exist and are accurate; given the absence of knowledge of gravitational forces, what methods were used to make the predictions.  
> **username_2**: There is a huge difference between asking about "constellation positions" which change very slowly due to precession. Star positions, some of which change very slowly due to proper motion and "planet positions" which change very rapidly. Its not clear what you mean, since the comments contradict the body of the question. The ancients could have made a good estimate of constellation positions, there model of the planets would be good for a few decades, but not for a few millenia  
> **username_0**: Very well put - would anyone know of any references to historical attempts to predict the slowly changing constellation positions and the more rapidly changing stars and planets?  
> **username_3**: I'd have said ancient astrologers were the first to attempt to predict the motion of constellations in the sky.  I'd suggest starting looking at that subject (which I'm not at all familiar with).  

---

## 2 answers

### Answer by username_4 on 2017-10-25. Score: 2 | Accepted answer

What you're asking for in the comments, on ancient predictions, that's a tricky subject. You're basically talking about proper motion and Edmund Halley was the first person to observe it. He recognized that 3 stars were about 1/2 a degree from where they were observed 1,850 years earlier.

[Source](https://en.wikipedia.org/wiki/Proper_motion#History).

1/2 of 1 degree in the night sky is larger than you might think. It's about the diameter of the full moon, but 1,850 years is a long time. That's why it went unnoticed until Halley took a closer look at the ancient star charts.

It's noted in the Wikipedia article that the ancient Greeks suspected proper motion happened but they were unable to observe it and nobody can make a decent prediction based on something that changes so slowly they are unable to observe it.

With today's observation methods, it's just a matter of running a computer simulation to see what the constellations will look like 100 years from now (virtually unchanged) or 10,000 years from now (some of them would begin to be visibly skewed but likely still recognizable).

Every star has it's own proper motion, so each constellation would undergo it's own rate of change.


---

### Answer by username_5 on 2017-09-23. Score: 3

No, there is no possible way that humans from any known civilization in the first century AD would have been able to extrapolate current constellation positions.

Prior to the work of [Johannes Kepler](https://en.wikipedia.org/wiki/Johannes_Kepler) and [Isaac Newton](https://en.wikipedia.org/wiki/Isaac_Newton), humans did not have sufficient knowledge of the basic principles of celestial movement to have any kind of basis for making such calculations.

Second, even if they had the basic principles, they would also have needed much more accurate and detailed information about the makeup of the Milky Way galaxy. The information currently available, that goes into the NASA models, is the product of a great many man-years invested in both observations and analysis of those observations.

Third, even if they had the basic principles and the necessary details with which to create a proper model, they lacked the computing power necessary to actually run the model - computation of that time being limited to pencil and paper (or perhaps an abacus).

> **Comments:**
> **username_0**: Would you feel that software models that "turn back the clock" are accurate?  
> **username_5**: @DougKimzey It is as accurate as we can currently make it. Not being an actual astronomer, I don't know what the limitations of our current understanding are.  

---

