I stumbled across the following image on Facebook, being reposted by people who should know better, and it awoke my inner HISTSCI_HULK:

I shall only be commenting on the first three images, if anybody has any criticism of the other ones, they’re welcome to add them in the comments.

To what extent Galileo developed his own telescope is debateable. He made a Dutch, telescope a model that had first been made public by Hans Lipperhey in September 1608. By using lenses of different focal lengths, he managed to increase the magnification, but then so did several others both at the same time and even before him.

Galileo was not the first to point the telescope skywards! As I have pointed out on several occasions, during that first demonstration by Lipperhey in Den Hague, the telescope was definitely pointed skywards:

The said glasses are very useful at sieges & in similar affairs, because one can distinguish from a mile’s distance & beyond several objects very well, as if they are very near & even the stars which normally are not visible for us, because of the scanty proportion and feeble sight of our eyes, can be seen with this instrument^[1]

Even amongst natural philosophers and astronomers, Galileo was not the first. We know that Thomas Harriot preceded him in making astronomical observations. It is not clear, but Simon Marius might have begun his telescopic astronomical observations before Galileo. Also, the astronomers of the Collegio Romano began telescopic observations before Galileo went public with his Sidereus Nuncius and who was earliest they or Galileo is not determinable.

I wrote a whole very detailed article about the fact that Newton definitively did not invent the reflecting telescope that you can read here.

By the standards of the day William Herschel’s 20-foot telescope, built in 1782 seven years before the 40-foot telescope, was already a gigantic telescope, so the 40-footer was not the first. Worse than this is the fact that the image if of one of his normal ‘small’ telescopes and not the 40-footer. 

Herschel’s 40-foot telescope Source: Wikimedia Commons

People spew out these supposedly informative/educational or whatever images/articles, which are sloppily researched or not at all and are full of avoidable error. To put it bluntly it really pisses me off!

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^[1] Embassies of the King of Siam Sent to His Excellency Prince Maurits Arrived in The Hague on 10 September 1608, Transcribed from the French original, translated into English and Dutch, introduced by Henk Zoomers and edited by Huib Zuidervaart after a copy in the Louwman Collection of Historic Telescopes, Wassenaar, 2008 pp. 48-49 (original pagination: 9-11)