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arXiv · 0804.0653

MOA-cam3: a wide-field mosaic CCD camera for a gravitational microlensing survey in New Zealand

T. Sako·T. Sekiguchi·M. Sasaki·K. Okajima·F. Abe·I. A. Bond·J. B. Hearnshaw·Y. Itow·K. Kamiya·P. M. Kilmartin·K. Masuda·Y. Matsubara·Y. Muraki·N. J. Rattenbury·D. J. Sullivan·T. Sumi·P. Tristram·T. Yanagisawa·P. C. M. Yock
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Abstract

We have developed a wide-field mosaic CCD camera, MOA-cam3, mounted at the prime focus of the Microlensing Observations in Astrophysics (MOA) 1.8-m telescope. The camera consists of ten E2V CCD4482 chips, each having 2kx4k pixels, and covers a 2.2 deg^2 field of view with a single exposure. The optical system is well optimized to realize uniform image quality over this wide field. The chips are constantly cooled by a cryocooler at -80C, at which temperature dark current noise is negligible for a typical 1-3 minute exposure. The CCD output charge is converted to a 16-bit digital signal by the GenIII system (Astronomical Research Cameras Inc.) and readout is within 25 seconds. Readout noise of 2--3 ADU (rms) is also negligible. We prepared a wide-band red filter for an effective microlensing survey and also Bessell V, I filters for standard astronomical studies. Microlensing studies have entered into a new era, which requires more statistics, and more rapid alerts to catch exotic light curves. Our new system is a powerful tool to realize both these requirements.

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T. Sako, T. Sekiguchi, M. Sasaki, K. Okajima, F. Abe, I. A. Bond, J. B. Hearnshaw, Y. Itow, K. Kamiya, P. M. Kilmartin, K. Masuda, Y. Matsubara, Y. Muraki, N. J. Rattenbury, D. J. Sullivan, T. Sumi, P. Tristram, T. Yanagisawa, P. C. M. Yock. 2008-04-04. MOA-cam3: a wide-field mosaic CCD camera for a gravitational microlensing survey in New Zealand. https://doi.org/10.1007/s10686-007-9082-5

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