Friday, September 14, 2012

Clear sky, donuts, and a marble

Almost overnight the Monsoon season came to an end. Northwestern weather systems are pressing the moist air out of Arizona, and the sky is clearing up rapidly. While Wednesday high humidity prevented us from opening the dome despite a beautiful clear sky, last night we finally saw star light again. 

During the first half of the night most images were out of focus. Intentionally, that is. By combining defocussed images where the focus has been moved inside and outside of the optimum location, one can reconstruct detailed information about the characteristics of the optical system (or more technically: one can reconstruct the wave front errors). This is what Chuck Claver from LSST and his team will do with the data we took, and provide us with hints how to optimally tune ODI's and the telescope's optic to get best images over the entire field of view.

Later the night with eastern winds the seeing at WIYN turned bad to more than 2". We used that time to prototype the workflow for automatic dithering of images. Just before calling it a night we also managed to capture Jupiter (which nicely fits into one OTA cell!), albeit I really look forward to repeat this exercise when the seeing is better.


Out of focus images ("donuts") used to analyze the imaging optics.

Jupiter – at a bad seeing of 2". WIYN can do better.

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