The COS Spherical Wave Interferometer
Reference Element

Reference Element Price: $410 USD + S/H

We accept personal checks (from customers in Canada and the U.S. only) as well as VISA. For VISA transactions add a 4% transaction fee.

Also available is the gradient index lens used as the diverging lens in the interferometer. The source, Melles-Griot, has a minimum order policy that can be onerous for the individual telescope maker, so we have purchased a batch and are pleased to provide them to the telescope making community.

Grin Lens Price: $45 USD

All payments to be made in USD.