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

The revised optics bid package from last week was discussed in some detail, again with considerable discussion on strategy and wording. The particular issue of concern is the bid for the corrector which is most likely the hardest part to make, and therefore considerable care is needed to make sure we put the right words and drawings in the right place to avoid confusion and result in a no-bid situation with the corrector. It is fairly clear that we can expect considerable iteration and communication with potential vendors over this optic. We are pretty clear that we most desire a round corrector as that is best from a number of standpoints if the corrector doubles as the window of a vacuum camera. There are clearly a number of issues to be discussed in a dialogue with the vendors.

After reviewing some of the final patches to the draft, we asked Paul to prepare the final version. Darren will review this document in detail, and will use it as the basis of our consultation with the liaison in University Purchasing to make sure we have not left anything out. If everything is approved, the bid package will be mailed out next week.

We will ask for a response from vendors by June 30. Paul has contacts with a number of the vendors and will keep in communication.

Gratings

Tom and Paul are looking into the issue of the grating size. We don't need to fill the full 300mm height we've set aside, more like 270x400mm. This size puts us, unsurprisingly, into the catalog of "Large Astronomical Gratings" kept by Spectronics Instruments (ex-Milton Roy, Ex-Bausch & Lomb, ex-Richardson Grating Labs, ex-...).

To get some idea of costs, we are going to seek two grating quotes from Spectronics:

1. A catalog grating with 622 l/mm, blaze 22.5-deg, which will deliver a center resolution of R=8000 and a blaze wavelength of ~600nm. We will ask for the price for the full-size grating (304x408mm) and with the corners lopped off. This is one of the closest "desirable" gratings in the current Spectronics catalog.

2. A new ruling for a master grating with 330 l/mm , blaze 7.5-degree, with a blaze wavelength of 700nm. This is a model for a "low-res" (R=4000) grating. Same size as above.

Paul has also analyzed all relevant gratings in the Spectronics large astronomical grating catalog in the MODS configuration. Paul will provide Rick and Darren with a table of their numbers and they will generate a report to appear on this web page in the near future.

Other Issues

Jim Breckenridge from NSF/ATI will not be visiting as planned because NSF has run out of travel money for this fiscal year. We will reschedule a visit for the near future.

We plan to meet again next week, same time same place (May 25).