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NORTHERNMOST/APEX CULMINATION TEST AT RAPA NUI (φ = -27.113°)
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Operator band tested: [16.0°, 20.0°] (operator θ₁ = 18°)

For each cruciform figure / control, the NORTHERNMOST bright star (mag < 3.0)
is the apex of the visual cross figure (or topmost vertex of the pentagon)
when observed from a southern-hemisphere latitude.

Figure                                           Apex/N-most star           Decl    h_max  In band?
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Cygnus (Northern Cross)                          Deneb (α Cyg)           +45.28°   17.61°  YES
Crux (Southern Cross)                            Gacrux (γ Cru)          -57.11°   60.00°  no
Auriga (pentagon, NOT cruciform — control)       Capella (α Aur)         +46.00°   16.89°  YES

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Figures whose apex star culminates in [16.0°, 20.0°]: 2
  -> Cygnus (Northern Cross): Deneb (α Cyg) at 17.61°
  -> Auriga (pentagon, NOT cruciform — control): Capella (α Aur) at 16.89°
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Notes on the result:

- Cygnus passes: its apex (Deneb) culminates at 17.61°, within the band.

- Crux fails the apex-altitude test: Gacrux, the northernmost bright
  star and the conventional 'top' of the Southern Cross diamond,
  culminates at 60.00° from Rapa Nui — far above the operator band.
  Crux is recognised as a cruciform figure (passes C2) and its apex
  is its northernmost bright star (passes C3 in the manuscript's
  Section 6.2 conjunction). It fails only on C1 (band condition).

- Auriga is a near-equilateral pentagon. There is no 'apex' or 'tail';
  the constellation does not have a single distinguished topmost point
  that defines its identity. Capella is its northernmost bright star
  and culminates at 16.89° (within the band), but Auriga fails C2
  (not cruciform) and C3 (no single apex) in the manuscript's screening.
