Page 156-157 from Edwin Hubble's observation notebook. It documents the
discovery of the first Cepheid variable star in the spiral nebulae M31.
Initially Hubble suspected that he had found a nova, a star that quickly
flares up in brightness and then slowly declines. For photographic plate
number 331, Hubble noted "Nova suspected." For plate 335, Hubble
wrote "confirm nova suspected …" But Hubble soon realized
that he had found not a nova but a Cepheid-type variable star.
Image
courtesy Norriss S. Hetherington |
