7.9 micron filter curve

Here is a copy of the OCLI 7.9 micron WARM filter curve. The filter was installed in EXES Dec 2010 before we left IRTF. Uses a CaF2 blocker.

Bach Echelle #4 Interferograms

Here are some interferograms from the 4th Bach grating. They believe this meets the specs and will ship it, but believe they can do better and will try. If the 5th grating is better, they'll send that one, too.

It sounds like the PV and RMS wavefront errors are already converted to 10.6 microns, which worries me a bit since I'm not sure these values are actually good enough. The one big error turns out to be a region being cut when the temperature control wasn't quite up to snuff, which is why they think they can do better.

Broadband filter curves

I've received two new filters from Spectrogon. The curves are attached. These filters are meant for use with the lower resolution side of the grating and will be located in the decker wheel.