The Project in Pictures

Three garages and uncountable hours of spare time were contributed.

Project 40 Rocker

Testing the Rocker Assembly, which houses the 40" mirror

Project 40 Steve FollettSteve Follett, our mirror-grinding expert, performing calculations for the next grinding operation

Project 40 Mirror

Len Nelson (left) and Larry McCune fine-tuning the mirror

For more photos and design considerations, see our
Project 40 blog.


Project 40

We've built a 40" Telescope!

Project 40 is a Valley of the Moon Observatory Association (VMOA) initiative to build a reflecting telescope with a 40-inch mirror to be used at the Robert Ferguson Observatory for public astronomy. This instrument has great light-gathering power, is easy for docents to use at public events, and easy for visitors to use and enjoy.

After 12 years in the making, the telescope was installed in December 2015, with final adjustments taking place in January 2016.



Left: The 40" mirror passed the star test! Thanks to Project 40 team members Larry McCune, Steve Follett, George Loyer and Mark Hilleman.

Photo by Len Nelson


Project 40 had several goals to make the new telescope as useful as possible to the VMOA in its mission to bring astronomy to the public. First, the optical path must end in an eyepiece at or near sitting height off of the floor. Second, the telescope must be constructed with visual astronomy as its first priority, with instruments only added if they can be integrated in a way that will not interfere with visual astronomy. Third, the telescope must be easy for docents to use to find an object and to keep the telescope pointed at that object without frequent adjustments.

The Project 40 team chose to build the telescope with a parabolic primary mirror, hyperbolic convex secondary mirror, and flat tertiary mirror. The design uses the partially completed truss tube design for the Optical Tube Assembly (OTA), and an altazimuth mounting driven by computer in both axes to track a found object in the sky. The telescope was designed to fit in the west wing of the Robert Ferguson Observatory, a 20-foot by 20-foot enclosed space with a roll-off roof and an existing set of three piers.

Project 40 was funded by the VMOA from existing funds and from funds raised from private parties, corporations and other non-profits interested in supporting the goals of the VMOA.