I will present a proposal for the exact gravitational partition function on a class of 3-manifolds with positive curvature and conical defects. Interpreted as 3D de Sitter gravity with a heavy backreacted observer, this allows us to compute certain observer correlators at finite G. More generally, our proposal applies to any 3-manifold with a hyperbolic-to-spherical transition as the cone angle is varied, including knot complements. The main ingredient is Virasoro TQFT, analytically continued in two complex conjugate directions. In the semiclassical limit, we check our proposal by matching to known classical saddles in 3D de Sitter with defects. This leads to a ‘spherical volume conjecture’ for the asymptotic behaviour of analytically continued Virasoro TQFT amplitudes. Lastly, we test our proposal on Seifert manifolds, which lack a hyperbolic regime but can have spherical saddle points. The resulting partition functions exhibit the expected exponential dependence on the spherical volume, with agreement at one loop for simple examples.