<p>Hi I am a novice in the field of astronomy. I want to find out the dates for lunar and solar eclipse 9000-11000 yrs ago. I found out that Stellarium is based on VSOP87 which is recommended for 4000 yrs ago. However, the software allows one to use DE431 which can provide planet ephemerides upto 13000 yrs ago. I am wondering if I can calculate eclipses observed in India accurately using DE431.</p>

CC BY-SA 4.0
2019-06-03T02:02:36.657Z
comment, not an answer: There may be other Q&A here on techniques and software options to find, predict, and model historical eclipses, but they may or may not answer your specific needs. I don't think Stellarium has any capability of solving for unknown eclipse dates, but I am not sure about that. Anyway, using one of the [Development Ephemerides](https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris) is probably your best bet for accuracy. But you need software to read them. Some options can be found in [this answer](https://astronomy.stackexchange.com/a/13489/7982)
uhoh
CC BY-SA 4.0
2019-06-03T16:57:34.103Z
One thing to bear in mind also is the uncertainty in the value of delta-T (Earth's rotation) and the Moon's secular acceleration. These parameters aren't known with great accuracy for such dates in the far past. [NASA](https://eclipse.gsfc.nasa.gov/SEcat5/uncertainty.html) estimates that the error in longitude for eclipse back-predictions 6000 years in the past could be as large as 68 degrees, which means an eclipse track could be off by thousands of kilometers.
FSimardGIS
CC BY-SA 4.0
2019-06-03T18:22:24.330Z
@uhoh I saw that answer earlier. Stellarium can read DE431 which is largest ephemerides file. I have never used the software therefore, I was wondering if anyone has the experience of using DE431 to calculate accurate eclipses 10000 yrs in the past.
sidharth chhabra
CC BY-SA 4.0
2019-06-03T18:28:59.097Z
@FSimardGIS DE431 accounts for the uncertainty in lunar motion using the numerical integration techniques. https://ipnpr.jpl.nasa.gov/progress_report/42-196/196C.pdf
sidharth chhabra
CC BY-SA 4.0
2019-06-03T19:13:50.367Z
@sidharth They take into account long term variations, but still the uncertainty for the position of the Moon in DE431 (as stated in the paper) is 28 m/century² so for 100 centuries in the past the uncertainty is +- 280 km along-track. As for the rotation of the Earth, it is even bigger than that.
FSimardGIS
CC BY-SA 4.0
2019-06-03T23:51:21.377Z
@FSimardGIS please forgive my ignorance but +-280 km shouldn't disturb the calculations of eclipse by +- day?
sidharth chhabra
CC BY-SA 4.0
2019-06-04T01:04:27.973Z
The accuracy for the position of the Moon indeed isn't so bad, however the biggest uncertainty for eclipse prediction (or back-prediction in your case) is the Earth's non-constant rotation. We do not know exactly how much the Earth has rotated since then, and that uncertainty is very large for such dates (more than 4 hours, or 68 degrees in 4000 BCE, even more in 8000 BCE) which means that the Earth's orientation could very well be half a rotation off the model-predicted orientation, but we do not have enough detailed records or observations before 1000 BCE to ascertain the value of delta-T.
FSimardGIS
<solar-eclipse><lunar-eclipse>
Stellarium software with DE431 for eclipse 10000 yrs ago
sidharth chhabra
# Stellarium software with DE431 for eclipse 10000 yrs ago

(Asked by: username_0 on 2019-06-03)

Hi I am a novice in the field of astronomy. I want to find out the dates for lunar and solar eclipse 9000-11000 yrs ago. I found out that Stellarium is based on VSOP87 which is recommended for 4000 yrs ago. However, the software allows one to use DE431 which can provide planet ephemerides upto 13000 yrs ago. I am wondering if I can calculate eclipses observed in India accurately using DE431.

**Tags:** solar-eclipse, lunar-eclipse
> **Comments:**
> **username_1**: comment, not an answer: There may be other Q&A here on techniques and software options to find, predict, and model historical eclipses, but they may or may not answer your specific needs. I don't think Stellarium has any capability of solving for unknown eclipse dates, but I am not sure about that. Anyway, using one of the [Development Ephemerides](https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris) is probably your best bet for accuracy. But you need software to read them. Some options can be found in [this answer](https://astronomy.stackexchange.com/a/13489/7982)  
> **username_2**: One thing to bear in mind also is the uncertainty in the value of delta-T (Earth's rotation) and the Moon's secular acceleration. These parameters aren't known with great accuracy for such dates in the far past. [NASA](https://eclipse.gsfc.nasa.gov/SEcat5/uncertainty.html) estimates that the error in longitude for eclipse back-predictions 6000 years in the past could be as large as 68 degrees, which means an eclipse track could be off by thousands of kilometers.  
> **username_0**: @uhoh I saw that answer earlier. Stellarium can read DE431 which is largest ephemerides file. I have never used the software therefore, I was wondering if anyone has the experience of using DE431 to calculate accurate eclipses 10000 yrs in the past.  
> **username_0**: @FSimardGIS DE431 accounts for the uncertainty in lunar motion using the numerical integration techniques. https://ipnpr.jpl.nasa.gov/progress_report/42-196/196C.pdf  
> **username_2**: @sidharth They take into account long term variations, but still the uncertainty for the position of the Moon in DE431 (as stated in the paper) is 28 m/century² so for 100 centuries in the past the uncertainty is +- 280 km along-track. As for the rotation of the Earth, it is even bigger than that.  
> **username_0**: @FSimardGIS please forgive my ignorance but +-280 km shouldn't disturb the calculations of eclipse by +- day?  
> **username_2**: The accuracy for the position of the Moon indeed isn't so bad, however the biggest uncertainty for eclipse prediction (or back-prediction in your case) is the Earth's non-constant rotation. We do not know exactly how much the Earth has rotated since then, and that uncertainty is very large for such dates (more than 4 hours, or 68 degrees in 4000 BCE, even more in 8000 BCE) which means that the Earth's orientation could very well be half a rotation off the model-predicted orientation, but we do not have enough detailed records or observations before 1000 BCE to ascertain the value of delta-T.  

---

## 0 answers

