TMT Work to Resume Says Ige!

[TomK]

PT wrote:

"The infrared noise at the summit of Mauna Kea is the sun heating the rocks during the day, doh! As for the upgrades, they are related to that."

I assume from this that the rocks at the TMT site are magic rocks that don't heat up during the day, then. In fact, what you are describing is ground-layer seeing, not "infrared noise", and it's a more significant problem at the TMT site than the summit ridge. The TMT site is on a plateau meaning more thermal mass surrounding it compared to the telescopes on the ridge. For telescopes such as the CFHT, Gemini and UKIRT, ground-layer seeing extends to about 100 feet above the ground. TMT site testing demonstrated the ground-layer effect extended much higher, over 300 feet.

E.g.,

http://sitedata.tmt.org/docs/TMT.SiteTes...-04-08.pdf

http://adsabs.harvard.edu/abs/2009MNRAS.394.1121C

And no, the upgrades aren't related as an upgraded infrared array will make no difference to ground-layer seeing. How could it? Adaptive optics, however, do, which is why the TMT will have such a system.

PS. Hope it was good popcorn, Pog!