OK. While we are waiting for the next end of the world, I want to show you another historical "black hole" The attached photo with stars is a photograph taken by Isaac Roberts at the end of the 19th century.
It depicts the structure of M31, the Great Nebula in Andromeda (now known as the Andromeda Galaxy). He took the picture on December 29, 1888, using his 20-inch aperture reflecting telescope, made by Howard Grubb of Dublin. Long exposure photographs showed that the nebula has a spiral structure, which was quite unexpected at the time.
Congratulations that the scientists of that time were surprised by the spiral shape of the object in the starry sky, I hope they were pleased.
I was surprised that at the same time when it was possible to photograph distant galaxies at a distance of 2.5 million light years, with a spiral structure on photographic film, other people of the same time make maps of the starry sky using this miracle apparatus that looks like sewing a machine for copper plates and probably burned tracks there, as they do now on printed circuit boards of electronic devices.
To be honest, I was too lazy to study the principle of operation of this sewing machine (but I attached a file with a detailed description). Perhaps that's why I still have a question - if you have powerful optics and photographs, why do you need engravings of the starry sky?
Promotional video:
Anyway, as we remember, when some were engaged in high-definition photography, others drew prints with a pencil in official publications. Well, I'm talking about the 19th century again.
