It is one of the largest optical telescopes in the world, but still quite inexpensive.

Before leaving, he took a final look at the mysterious sky object through the optical telescope.

Since dark matter is invisible, how can an optical telescope see it?

It is the first optical telescope to orbit the Earth.

Currently, a 130-cm optical telescope is installed at the site.

The $125 million, 600-inch device will be the most powerful optical telescope in the world.

I don't even look through optical telescopes any more; it's not worth the effort.

It is one of the largest optical telescopes in the world.

Further, his workshop developed the optical telescopes which were a necessary component of the system.

We should need a good optical telescope, although not necessarily a very large one.