Last week I got back from a great work-pleasure jaunt to the United States. I started off in Tucson, Arizona, where I met with the MIRI test and calibration team to further our plans for
space domination instrument testing, calibration and software development for our instrument, which will be launched on board the James Webb Space Telescope in 2018. I’ve been involved in testing MIRI for my entire postdoc career now and it’s always a pleasure to meet with the team, and see how far we’ve come in the project.
Many people ask me what there is left or us to do, now that MIRI is in the hands of NASA in the US. The answer to that is “LOTS”. Even though the immediate task of assembling and testing the actual instrument hardware is completed, we now have to work with our NASA colleagues to integrate MIRI further with the rest of the spacecraft and test over and over again that everything is still in working order. In addition, we have to define calibration procedures and the data and algorithms that are required for that, and develop software. There’s an awful lot of work still happening!
Aside from the productive meeting I was really pleased to get a tour of the Steward Mirror Lab, which I’d heard lots about. Several of the world’s largest astronomical mirrors were cast and polished in giant spinning ovens, deep in the bowels of the University of Arizona’s football stadium . In these ovens, heat melts the glass until it’s molten, and the rotation shapes it into a nice parabolic shape while it’s in that state. The temperature is then lowered very slowly in a controlled way to stop stresses and bubbles forming in the glass. The mirror is shaped around a honeycomb structure that is later removed, producing a nice lightweight mirror.
With this technology Steward produced the mirrors for the 3.5-m mirrors for the ARC at Apache Point, New Mexico, and the WIYN at Kitt Peak, AZ; the 6.5-m’s for Magellan in Chile and for MMT at Mt. Hopkins, AZ; and the twin 8.4-m mirrors for the Large Binocular Telescope at Mt. Graham, also in Arizona.
Excitingly, several large mirrors are currently in production there at the moment. The first two 8-m segments for the Giant Magellan Telescope have been produced, and a third is under way. The primary mirror for the Large Synoptic Survey Telescope (LSST) was being polished while I was there. This mirror is pretty amazing, as it contains both the blanks for the primary and the tertiary mirror, so two different profiles are being polished into it. I’ve included some pictures below [feel free to use them but please credit to me when you do!].