IRMA calibrations and data analysis for telescope site selection

Our group has developed a 20 μm passive atmospheric water vapour monitor. The Infrared Radiometer for Millimetre Astronomy (IRMA) has been commissioned and deployed for site testing for the Thirty Meter Telescope (TMT) and the Giant Magellan Telescope (GMT). Measuring precipitable water vapour (PWV) requires both a sophisticated atmospheric model (BTRAM) and an instrument (IRMA). Atmospheric models depend on atmospheric profiles. Most profiles are generic in nature, representing only a latitude in some cases. Site-specific atmospheric profiles are required to accurately simulate the atmosphere above any location on Earth. These profiles can be created from publicly available archives of radiosonde data, that offer nearly global coverage. Having created a site-specific profile and model, it is necessary to determine the PWV sensitivity to the input parameter uncertainties used in the model. The instrument must also be properly calibrated. In this thesis, I describe the radiometric calibration of the IRMA instrument, and the creation and analysis of site-specific atmospheric models for use with the IRMA instrument in its capacity as an atmospheric water vapour monitor for site testing. Acknowledgements I’d like to thank David Naylor for welcoming me into the Astronomical Instrumentation Group. It’s every bit as off-the-wall as he had originally hailed it to be. Thanks to the group for always being so helpful. Locke for happily stopping whatever he was doing to help, whether it be with an equation, or hauling hundreds of kilograms of scrap lumber. Regan for tolerating what must have sometimes felt like incessant questioning in regards to IRMA software, or computer related issues in general. Regan, you’ve been infinitely helpful, and I thank you for that. Greg for bringing light and laughter into the lab, whether that be with magnets, moon landing hoaxes or your disdain for relativity. Your knowledge of the IRMA electronics is amazing. It’s been great being here in Chile with you. I’d like to acknowledge the previous people who have brought the IRMA project to where it is today. Graeme, whom I haven’t met, started the IRMA work. Ian C. for creating ULTRAM, without which none of the site-specific atmospheric modeling could have been done. Ian S. for building up the communication and control system that serves as the backbone for the IRMA hardware. Dr. Robin Phillips for his work as Project Manager, integrating the cryocooler, helping to make IRMA-III capable of remote operation, and beginning the Antarctic IRMA retrofit process. Thanks to Scott Jones for all his help around the lab. Thanks to Dan Sirbu for all his work too. I’d also like to thank Matthias Schöck, Project Manager, TMT Site Testing Committee, for his help calibrating the TMT IRMA units. Thank you to Joanna Thomas-Osip for her help in both Lethbridge and Las Campanas, getting the LCO IRMA unit up and running, and troubleshooting as we went along. Thanks to Drs. Peter Ade and Carole Tucker, University of Cardiff, for supplying us with specially designed IR filters. Thanks to Fluke for loaning us the Ti20 Thermal Imager that started us down the calibration rabbit-hole. Thanks to NSERC, HIA and NRC for funding the IRMA project. I’m grateful for all of my friends and family, most of whom haven’t seen me lately. The trials of a graduate student I’m told. No need to worry, I can already smell the green grass. I’m especially grateful to have Cindy in my life, I look forward to spending much more time together. It’s been a long while. Thank you again to David Naylor for painstakingly going over and revising and editing this thesis. You’ve been a wonderful help, without which this thesis would have taken on a very different form. Thank you for your time. —RRQ, September 2007, LCO, Chile