Wide Field
Wide Field Corrector

Photo Gallery


M52 Images Using the 1 Degree Field (Spectroscopic Corrector Configuration)


Wide Field Corrector Manual

Design of a cell for the wide-field corrector for the converted MMT

PI: Daniel Fabricant
Project Engineer: Robert Fata

The Wide Field Corrector consists of a group of lenses that remove off-axis aberrations at the f/5 focus of the converted MMT, allowing the telescope to offer excellent images over a very large field.

The Wide Field Corrector has two modes of operation. It can be used for wide field spectroscopy, in which case it has a 1° diameter field. The spectroscopic field is curved (8 mm sag) but highly telecentric. In its imaging mode, the corrector has a 0.5° diameter field and a flat focal surface.

The system works over the 320 to 1800 nm range, but the anti-reflection coatings are optimized for the 320 to 1000 nm range. Atmospheric dispersion compensation prisms are included in the spectroscopic mode.

Sol-Gel anti-reflective coatings have been applied to the lenses and ADC prisms by Cleveland Crystals.

As of June 18, 2003 commissioning of the f/5 secondary and the spectroscopic mode of the f/5 corrector (1 degree field) has been completed. All of the optics have the correct surfaces and are located correctly. On-axis, the best images that we have recorded have 0.4 arcseconds FWHM. At the edge of the spectroscopic field the best recorded images have 0.5 arcseconds FWHM, near the limit allowed by the optical design. Commissioning of the imaging configuration the corrector followed in November 2003 with the commissioning of Megacam. Megacam has achieved 0.4" images across the full 24' x 24' field of view.