Historical Organization
Mount Wilson Observatory
On the night of 5–6 October Hubble photographed a spiral arm of Andromeda.
Hubble initially marked three suspected novae on the image; later comparisons revealed one was variable.
The 100-inch telescope recorded faint points in Andromeda that could be compared across nights.
The photographic plate later helped establish that Andromeda lies outside the Milky Way; this conclusion was later, not on the exposure date.
