Here's why:

* Hubble's primary mirror is 2.4 meters (94.5 inches) in diameter.

* A 100-inch telescope refers to the Hale Telescope at Palomar Observatory, which was a significant telescope at the time of its construction.

So, while both telescopes are impressive and have contributed significantly to our understanding of the universe, they are distinct in their size and location (Hubble is in space, Hale is on Earth).