lib_vsop_core

Library "lib_vsop_core"
Foundation library providing core types, evaluators, and utilities
for VSOP87 planetary theory calculations. Required by all planetary
libraries. Includes Earth heliocentric model and Sun geocentric functions.

Author BlueprintResearch (Javonnii)
license MIT License - Free to use with attribution


theory VSOP87 (Variations Séculaires des Orbites Planétaires)
ACCURACY Truncated series - suitable for financial astrology and education
@time_scale Julian millennia from J2000.0 for VSOP87 planets
Julian centuries from J2000.0 for Moon and Pluto

reference Meeus, Jean. "Astronomical Algorithms" (2nd Ed., 1998)
Bretagnon & Francou. "VSOP87 Solutions" (1988)

showcase Includes commented showcase code with 250-bar future projection.
Uncomment to display Sun/Earth data with polyline projections.

@open_source This library is part of an open-source alternative to
proprietary astronomical libraries. Study, modify, and
share freely. We believe knowledge of the cosmos belongs
to everyone.

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© 2025 BlueprintResearch / Javonnii
Licensed under MIT License
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version=6

get_julian_millennia(time_)
  Parameters:
    time_ (float)

get_julian_centuries(time_)
  Parameters:
    time_ (float)

eval_vsop87(terms, t)
  Parameters:
    terms (array<vsop_term>)
    t (float)

eval_vsop87_derivative(terms, t)
  Parameters:
    terms (array<vsop_term>)
    t (float)

mod360(x)
  Parameters:
    x (float)

custom_atan2(y, x)
  Parameters:
    y (float)
    x (float)

get_earth_helio_radius(t)
  Parameters:
    t (float)

get_earth_helio_coords(t)
  Parameters:
    t (float)

get_obliquity(t)
  Parameters:
    t (float)

get_earth_helio_lon(t)
  Parameters:
    t (float)

get_sun_geo_lon(t)
  Parameters:
    t (float)

get_sun_geo_speed(t)
  Parameters:
    t (float)

get_sun_decl(t)
  Parameters:
    t (float)

get_bar_gap_ms()
  Get bar interval in milliseconds for current timeframe
  Returns: (int) Time interval between bars in milliseconds

get_future_time(current_time, bars_ahead)
  Calculate future timestamp for projection plotting
  Parameters:
    current_time (int): (int) Current bar time in milliseconds (use built-in 'time')
    bars_ahead (int): (int) Number of bars to project into future
  Returns: (int) Future timestamp suitable for xloc.bar_time and chart.point.from_time

is_projection_bar()
  Check if current bar is suitable for drawing future projections
  Returns: (bool) True on last bar when projections should be drawn

vsop_term
  Fields:
    amp (series float)
    phase (series float)
    freq (series float)