Optical Filters

Optical Instruments
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Large filters for next-generation wide field camera

Next-generation wide field cameras such as Dark Energy Camera (DECam), One Degree Imager (ODI), Hyper Suprime-Cam (HSC),
Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) now come of age.
And Zwicky Transient Facility (ZTF) or Large Synoptic Survey Telescope (LSST) will have first light in the near future.

Asahi has provided DES 620 mm g, r, i, z, y / DECam u, VR filters to Blanco Telescope at CTIO, and HSC 600 mm g', z', Y filters to
Subaru Telescope in Hawaii by our proprietary large magnetron sputtering coater during 2011-2014.

We fabricated 445 mm x 428 mm u' band filter for the ODI at WIYN Observatory in Arizona in 2015,
that was a long-absent filter for the ODI.
We also suceeded in siginificantly improving 600 mm r-band filter for the HSC in terms of coating uniformity and transmission in 2016.
It will be replaced from the current r-band filter produced by another vendor several years ago.

Our goals are to achieve the ultimate coating uniformity (< 0.2% of wavelength) over the clear aperture and the higher transmission
in passband to shorten the exposure time as much as possible together.
These performances enable wide field cameras to be more poweful instrument for your surveys.

445 mm x 428 mm u' band filter for the One Degree Imager

figure One Degree Imager

Asahi was successful in coating the large 445 mm x 428 mm u' band filter for the One Degree Imager in last November.
It was safely delivered and installed in the One Degree Imager at WIYN Observatory in Arizona.
Though u' band filter is the hardest of the broad bandpass filters especially in larger size, it met all the requirements completely by
WIYN Consortium.

New 600 mm r-band filter for Hyper Suprime-Cam

figure Hyper Suprime-Cam

Asahi past experiences to provide large filters