Discussion Overview
The discussion focuses on calculating the apparent geocentric positions of Spica, the sun, and the moon with high accuracy. Participants explore various astronomical corrections that may be applied, including proper motion, precession, and others, while considering the implications of these corrections on their calculations.
Discussion Character
- Technical explanation
- Mathematical reasoning
- Debate/contested
Main Points Raised
- One participant lists seven corrections to consider for calculating the positions of Spica, the sun, and the moon, and asks about the order and necessity of these corrections.
- Another participant suggests that the necessity of corrections depends on the desired accuracy and time scale, questioning what constitutes "high-accuracy."
- A participant specifies a need for geocentric apparent positions to the nearest tenth of an arc-second and requests guidance on which corrections can be omitted.
- It is noted that gravitational deflection is negligible unless celestial bodies are closely aligned.
- Participants discuss the importance of data sources and how they influence the relevance of certain corrections, particularly for theoretical versus empirical calculations.
- One participant evaluates the significance of various corrections, concluding that proper motion and precession must be included, while annual parallax can be neglected.
- Questions arise regarding the necessity of stellar aberration corrections for the moon and the extent of gravitational deflection when a star is positioned behind the sun.
Areas of Agreement / Disagreement
Participants express differing views on the necessity and impact of specific corrections, indicating that multiple competing perspectives remain regarding which corrections are essential for achieving the desired accuracy.
Contextual Notes
Participants mention the importance of the data being used for calculations, which may affect the relevance of certain corrections. There is also uncertainty regarding the specific impact of the rotation of the ecliptic on the calculations for Spica.