Doane Observatory: This observatory, located behind the planetarium is home to the largest aperture telescope in the Chicago area.

Expect to pay $600 to $1,000 for a well-made 6- to 8-inch aperture telescope.

The camera was originally hand-guided through one of two 10-inch (25.5 cm) aperture refracting telescopes mounted on either side of the camera.

Brown pointed out that the organizations' objectives could be met with smaller aperture telescopes which would be less expensive to build, deploy, and operate.

His instrument of discovery was a 4-inch aperture telescope located in his sixth floor apartment in the Latin Quarter of Paris.

But the retrofit of such a large aperture telescope was a problem.

NPOI is expected to grow significantly in capability with the pending addition of four 1.8-meter aperture IR/Optical telescopes into the current array.

An Obsession Telescope 25" was the largest aperture telescope at the Custer Observatory in New York State for a time.

The cluster can be observed with binoculars or a small telescope, while a 12-inch aperture telescope will reveal about 250 stars.

Beyond building a large aperture telescope, they offer related instrumentation and services to those in amateur, professional and educational fields of astronomy.