"Precision thermal control technology to enable thermally stable telescopes," by Thomas E. Brooks and H. Philip Stahl has been published in the Journal of Astronomical Telescopes, Instruments and Systems (JATIS) http://dx.doi.org/10.1117/1.JATIS.8.2.024001. The paper summarizes results from the Precision Thermal Control ISFM directed research study, including: demonstrating better than 2-mK root-mean-square stable thermal control of the 1.5-m ultra-low expansion (ULE®) Advanced Mirror Technology Development-2 (AMTD-2) mirror when exposed to thermal disturbances in a relevant thermal/vacuum environment in the XRCF; an ability to shape the 1.5-m AMTD-2 mirror to picometer precision; and an analysis approach for quantifying thermally induced mid-spatial frequency error which can cause speckle noise in the coronagraph dark hole.
Figure: 1.5-m AMTD-2 mirror was placed in MSFC’s x-ray computer tomography test setup and (b) its internal structure quantified.