About accuracy and resolution

Abstract

Erik Høg clears up a common misunderstanding that optical resolution supposedly sets the limit for precision in astrometric measurements. He clearly goes over the distinction between resolution (λ/D) and measurement accuracy (σ ∝ λ / (πD√N)) and shows that the human eye and early telescopes could measure positions with an accuracy far beyond their resolution thanks to lots of photons and good technique. The article also highlights statistical signal processing in modern astrometry and challenges the idea that, for example, Tycho Brahe's measurements would be limited by the eye's resolution. A short reply from Jens Højgaard Jensen acknowledges the mistake and praises the genre as educational.