Rotation, revolution, peculiar drift, galactic orbit, Local Group, CMB
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Honesty
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True pitch — the helix as the numbers give it, not as it is usually drawn
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Velocity vectors and their magnitudes
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The galactic plane grid and the ecliptic
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This card
What is measured. The frame chain is J2000 throughout: obliquity 23.4392911°, galactic pole and centre from
the ICRS definition, so the 60.19° between the ecliptic and the galactic plane is derived here rather than quoted.
R₀ = 8.178 kpc is GRAVITY 2019; the circular speed 229 km s⁻¹ is Eilers et al. 2019; the solar peculiar motion is
Schönrich, Binney & Dehnen 2010; the 369.82 km s⁻¹ dipole and its apex are Planck 2018. What is modelled. The Earth-Moon barycentre is a Keplerian two-body orbit on JPL's fitted elements and secular
rates — nominally within 20 arcseconds in longitude over 1800–2050, but still not an ephemeris. Parallax carries
VSOP87 when arcseconds matter. The Sun's galactic path is a circle at R₀ with the peculiar drift integrated straight:
over the decades drawn here the epicycle has not begun to curve.
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