The story of telescopes is also the story of glass and it's development
The telescope nerd visited the museum to check out various things including their glass as it relates to telescopes. If you are a telescope maker you are very familiar with corning glass. It is the most commonly used glass for grinding out your own mirrors (Pyrex).
Pyrex is a strong glass and has extremely low distortion at temperature changes. It is great for telescopes. And the Corning company make Pyrex for just small telescopes. They have also tackled the challenges of making some of the largest telescope glass in the world including the 200 inch mirror in the Hale telescope at Mount Palomar. I visited Mount Palomar. You can see that here.
They have in the Corning museum the first cast of the Hale 200 inch mirror blank. It cracked while cooling and they keep it at the Corning museum. They learned a lot from this one and cast a second one. This second one took almost a year to cool! The person walking at the left is a good reference for you to understand how large this mirror blank really is.
When the successful second cast was shipped to Palomar Observatory it went on a special built railroad car. It was quite a celebrity that made newspapers. And it stopped at various cities for the public. And it was encased in a bullet proof shroud. And good thing because when it arrived at it's destination they found bullet pock marks in it.
They also have a 100 inch blank:
Here is a beautiful glass bodied catadioptric telescope. I just think it is kind of nice that they made the outer body out of glass so you can see how the telescope works.
Here is a glass bodied refractor.
They have lots of informational displays showing how glass has changed and improved both telescope performance and microscope performance. This next picture shows three things. On the left is a singlet lens, in the middle is a doublet lens and on the right is a triplet lens. You can easily see by the gridlines how each is an improvement on the previous.
Want to see an easy explanation of singlet doublet and triplet? ... I have it, with drawings right here: The different types of telescope lenses
Corning has also made the glass for other world class and ground breaking telescopes including The Hubble, The Subaru, and the Hooker telescopes.