ELP82b / Lunar tables doubt....

[cptolemy]

Hi,

I'm programming a simple DLL to use VSOP87 and ELP82b.

I can get the correct x,y and z values without a problem referred to J2000, I think.

But I'm getting a constant error when applying the correction for the nutation and precession in ELP82b. Actually, I'm getting even worst values than the Lunar Tables from 4000BC to 8000DC of Chapront.

The precession is rather simple - and the nutation is just adding. But maybe I'm missing the correct algorithms to do so.

Any ideas - or sources - for this?

Kind regards,

CPtolemy

 

[AndyW]

Hi CPtolemy,

Thank you for sharing your progress on your DLL project. It sounds like you are having trouble with the nutation and precession corrections in ELP82b. These corrections are important for accurately calculating the positions of celestial bodies over long periods of time.

One potential source of error could be the algorithms you are using for the corrections. Make sure you are using the most up-to-date and accurate algorithms for nutation and precession. You may also want to check for any typos or errors in your code that could be causing the discrepancies.

Another possibility could be the data you are using for the corrections. Make sure you are using the correct data for the time period you are interested in. Depending on the accuracy you require, you may need to use more precise data or consider incorporating additional factors such as tidal effects.

I would also recommend checking with other sources or experts in the field to see if they have encountered similar issues and how they have addressed them. Collaborating with others can often lead to valuable insights and solutions.

I hope these suggestions help you to resolve the issue with your nutation and precession corrections. Good luck with your project!