All posts by Henry Weiland

About Henry Weiland

ATLAS Observatory Systems Engineer

Don't Drop It

New Schmidt Correctors Installed!

ATLAS is happy to report that we have recently replaced the Schmidt correctors on both of our telescopes!  The original Schmidt correctors did not make really sharp images even at best focus, so our DFM telescope was not performing at its real capability.  The new correctors from Coherent make star images that are only 2 pixels wide!

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Unwrapping of the Coherent corrector, which was very nicely packaged and shipped in a Pelican Case.

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Replacing the correctors was straight-forward and without any trouble.  The procedure was fairly short, and involved removing the top portion of the OTA, which holds the mechanical shutter and corrector plate.  Then, we came up with a very simple yet elegant plan to remove the corrector from its cell by simply lowering the top portion of the OTA onto a bar stool, and allowing the stool to capture and “lift” the corrector plate right out of the top portion of the OTA.

Once we replaced the correctors (we all know the dreaded new-telescope-equipment curse which causes clouds to form overhead for days or even weeks following) and were able to take first-light images, the new images revealed slight optical misalignments of our telescopes that were previously undetectable.  This brought on a period of detective work figuring out the misalignments through ray-tracing, followed by several long, cold nights sitting beside the telescope making minute adjustments.

However, all the hard work from the ATLAS team paid off, and we saw a great increase in performance that was reflected in things such as our PSF and sensitivity gain.  We are quite pleased with the results and are loving the new, sharp star images across the entire field.

before
A small crop of 14 arcmins before alignment corrections.
The same 14' crop after corrections were applied
The same 14′ crop after corrections were applied, now with 2px FWHM.