JoeSchmuckatelli Posted December 29, 2022 Share Posted December 29, 2022 Back when Hubble (the astronomer) was doing his work, negatives were the norm. http://ircamera.as.arizona.edu/NatSci102/NatSci102/images/m33hub.jpg Here is one of Hubble's photographic plates of the center of M33, with Cepheid variables marked. If you look closely (and if the original resolution has been preserved from plate to journal to scanner to web page to your computer), you will see that the gray "nebulosity" is broken up into little specks that are individual stars. (The plate is a negative, as was the convention for publishing results -- the stars look black and the sky white) (From ApJ, 63, 236, 1926) Quote Link to comment Share on other sites More sharing options...
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