Convert to "Of Date" Apparent coordinates from "J2000" coordinates

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SUMMARY

This discussion focuses on converting "J2000" coordinates to "Of Date" or "Apparent" coordinates in astronomy. The JPL Horizons system provides both coordinate types, with Astrometric representing J2000 and Apparent representing "Of Date". Tools such as Stellarium and resources like Jan Meeus's books are recommended for further understanding. The conversation emphasizes the need for programming skills in languages like C or FORTRAN for more complex calculations.

PREREQUISITES
  • Understanding of J2000 coordinate system
  • Familiarity with "Of Date" or "Apparent" coordinates
  • Basic programming skills in C or FORTRAN
  • Knowledge of astronomical software like Stellarium
NEXT STEPS
  • Explore the JPL Horizons system for astronomical calculations
  • Learn how to use Stellarium for coordinate conversions
  • Study Jan Meeus's books on astronomy for foundational knowledge
  • Research algorithms for converting between J2000 and Apparent coordinates
USEFUL FOR

Astronomers, astrophysics students, software developers in astronomy, and anyone interested in celestial coordinate systems and their conversions.

Philosophaie
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How do you convert to "Of Date" or "Apparent" coordinates from "J2000" coordinates?

The website:
http://ssd.jpl.nasa.gov/horizons.cgi#results
there are two options for displaying RA and DEC: Astrometric and Apparent. Astrometric is the J2000 coordinates and Apparent is the "Of Date".

http://www.ephemeris.com/goto.php
Just lists the Apparent

www.stellarium.org software
Lists both "Of Date" and J2000 coordinates.

My question is: Is there a formula to convert between the two coordinate systems?
 
Short answer - what are you trying to do? Can you write programs in some language like maybe C or FORTRAN?
I suppose you can use a sophisticated programmable TI calculator...
@D H probably can help with a lot more detail - the JPL has software that does astronomical calculations. And copes with Jxxxx. AFAIK.

Jan Meeus has several books meant for amateur astronomers. Please consider one of them as a great starting point.
Exmple: https://www.amazon.com/dp/0943396352/?tag=pfamazon01-20

As an aside - are you trying to project orbits of Solar System objects into the future? All of what I did was always okay with existing ephemera.
 
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