First, thank you for developing this amazing tool! I noticed an inconsistency in celestial coordinates when comparing geocentric and heliocentric frames at the J2000 epoch moment (2000-01-01 12:00 TT), which appears to violate fundamental astronomical principles.
Steps to Reproduce
Set observation time to 2000-01-01 20:00 UTC+8 (equivalent to J2000 epoch: 2000-01-01 12:00 TT)
Enable both geocentric and heliocentric coordinate systems
Observe Earth's heliocentric coordinates and Sun's geocentric coordinates simultaneously
Expected Behavior
At the J2000 epoch moment:
Instantaneous coordinates should match J2000.0 coordinates exactly (neglecting negligible short-term effects)
Earth's heliocentric position and Sun's geocentric position should show mirrored coordinates (Δλ ≈ 180°)
Actual Results**
Significant discrepancies observed:
Earth (Heliocentric):
J2000.0 Ecliptic Lon: 100.1667°
Current Ecliptic Lon: 84.7680° (Δ15.4°!)
Sun (Geocentric):
J2000.0 Ecliptic Lon: 280.3707°
Current Ecliotic Lon: 280.3668° (Δ0.0039°)
Mirror Relationship Test:
Δλ between Earth's J2000 heliocentric and Sun's J2000 geocentric:
280.3707° - 100.1667° = 180.204° (0.204° deviation)
Technical Analysis**
Epoch Consistency Failure:
The 15.4° shift in Earth's heliocentric coordinates violates J2000 epoch definition. Precession/nutation (<1'/year) and light travel time (~8m) can't explain this magnitude.
Time System Suspicions:
UTC-TT conversion appears correct (20:00 UTC+8 ↔ 12:00 TT), but coordinate calculations might be using an unintended temporal reference.
Frame Transformation Anomaly:
The near-180° mirror relationship suggests correct frame polarity but reveals a possible error in precession initialization during heliocentric coordinate transformations.
Suggested Checks**
Verify time system conversions in heliocentric frame calculations
Audit precession model application during J2000 epoch initialization
Confirm coordinate transformation matrices for Earth-Sun frame reciprocity
System Info**
Stellarium v0.24.4
Config File: [Attached stellarium.ini snippet]
OS: Windows 11 23H2
config.ini.csv
Thank you for investigating this fundamental coordinate consistency issue. Let me know if additional data or tests would be helpful!
First, thank you for developing this amazing tool! I noticed an inconsistency in celestial coordinates when comparing geocentric and heliocentric frames at the J2000 epoch moment (2000-01-01 12:00 TT), which appears to violate fundamental astronomical principles.
Steps to Reproduce
Set observation time to 2000-01-01 20:00 UTC+8 (equivalent to J2000 epoch: 2000-01-01 12:00 TT)
Enable both geocentric and heliocentric coordinate systems
Observe Earth's heliocentric coordinates and Sun's geocentric coordinates simultaneously
Expected Behavior
At the J2000 epoch moment:
Instantaneous coordinates should match J2000.0 coordinates exactly (neglecting negligible short-term effects)
Earth's heliocentric position and Sun's geocentric position should show mirrored coordinates (Δλ ≈ 180°)
Actual Results**
Significant discrepancies observed:
Earth (Heliocentric):
J2000.0 Ecliptic Lon: 100.1667°
Current Ecliptic Lon: 84.7680° (Δ15.4°!)
Sun (Geocentric):
J2000.0 Ecliptic Lon: 280.3707°
Current Ecliotic Lon: 280.3668° (Δ0.0039°)
Mirror Relationship Test:
Δλ between Earth's J2000 heliocentric and Sun's J2000 geocentric:
280.3707° - 100.1667° = 180.204° (0.204° deviation)
Technical Analysis**
Epoch Consistency Failure:
The 15.4° shift in Earth's heliocentric coordinates violates J2000 epoch definition. Precession/nutation (<1'/year) and light travel time (~8m) can't explain this magnitude.
Time System Suspicions:
UTC-TT conversion appears correct (20:00 UTC+8 ↔ 12:00 TT), but coordinate calculations might be using an unintended temporal reference.
Frame Transformation Anomaly:
The near-180° mirror relationship suggests correct frame polarity but reveals a possible error in precession initialization during heliocentric coordinate transformations.
Suggested Checks**
Verify time system conversions in heliocentric frame calculations
Audit precession model application during J2000 epoch initialization
Confirm coordinate transformation matrices for Earth-Sun frame reciprocity
System Info**
Stellarium v0.24.4
Config File: [Attached stellarium.ini snippet]
OS: Windows 11 23H2
config.ini.csv
Thank you for investigating this fundamental coordinate consistency issue. Let me know if additional data or tests would be helpful!