The Ohio State University College of Mathematical & Physical Sciences Department of Astronomy

Attendees: Pat Osmer, Dan Papallardo, Bruce Atwood, Paul Byard, Tom O'Brien, Mark Derwent, Darren DePoy, Jen Marshall, & Rick Pogge,

Optics

In planning how to integrate the optics for MODS, it is clear we will want to ahve the camera components first (camera primary mirror, camera corrector lens, and field-flattener lens; noting that the field flattener is also the CCD dewar window).

It looks like the blue camera corrector's fused silica substrates, ordered from Corning Glass Works, will likely be delivered in January 2002 if all goes well. If reports from various substrate vendors (Hextek for the mirror blanks, Ohara for the BK7 glass, Thermo/RGL for gratings) are taken at face value, we could easily have all of the optics raw materials in hand by mid-2003.

What is needed for the Phase 1 MODS are:

Minimum Requirements:

Collimator, Camera Primary, Camera Corrector, and Field Flattener, imaging flat and the low-resolution (R=2000) grating. All are blue-channel optics.

Optimal Requirements:

Minimum optics above, plus the field lens (located behind the slit).

Flats for the imaging mirrors will be made of either pyrex or zerodur, while the gratings will made of zerodur (avoids problems with changes in groove spacing with temperature - Thermo/RGL will only make replica gratings on zerodur substrates). We are awaiting final substrate quotes from Thermo/RGL.

Given summer travel schedules, we will hold the next MODS team meeting when there are enough poeple in town at once...

R. Pogge, 2001 July 18