It's a bit tricky to pinpoint the exact age of the inventor of the telescope because it's more accurate to say the telescope was developed over time, not invented by a single person. However, here's what we know:

* Hans Lippershey, a Dutch lensmaker, is often credited with applying for the first patent for a telescope in 1608. He was likely in his late 40s or early 50s at the time.

* Galileo Galilei, an Italian astronomer, heard about Lippershey's invention and quickly built his own improved version in 1609. He was 45 years old at the time.

So, depending on who you consider the "inventor," the age would be either in the late 40s or mid-40s.

It's important to remember that the telescope wasn't a sudden invention. People were experimenting with lenses and optics for centuries before Lippershey. He simply combined existing knowledge and technology in a way that led to the first recognized practical telescope.