In 2006, NAOJ proposed to construct the Hyper Suprime-Cam (HSC) as a second generation instrument for Subaru telescope. This is a very wide-field camera covering 1.5 degrees of sky at a time. The focal plane area to be covered will be around 530mm. A total of 110 2kx4k CCD detectors will be placed adjacent to each other in order to cover this large field of view. The HSC will be a prime focus camera, and will enlarge the current field of view (FOV) of Subaru, as provided by the first generation Suprime Cam, by a factor of 10. The HSC will be the largest CCD camera in the world, and will have a total performance, as measured by the product of the telescope aperture area and the field of view, which will exceed that of all other telescopes. Only the planned LSST will have a better performance, but that will be in a time frame of three or more years later than the HSC.
The main scientific goal of the HSC will be weak lensing studies over large areas of the sky. Approximately 1000 square degrees will be surveyed every year. Weak lensing distortions of background galaxies due to the large scale structure, so called cosmic shear, will be examined. From statistical properties of cosmic shear, the properties of dark energy will be constrained. Along with the weak lensing study, a large survey project is planned to use more than 200 nights of HSC and Subaru to cover interesting science topics with the large dataset.
The HSC has now been funded by Japan. ASIAA has been invited by NAOJ to join in on this project. This is the continuation of the growing collaboration between Taiwan and Japan. In 2005, ASIAA joined the ALMA project via NAOJ. In the same year, the East Asian Core Observatories Association (EACOA) was established to promote joint future developments in astronomy in Asia. Taiwan, together with Japan, China, and Korea, are founding members of EACOA. Astronomy is developing rapidly in North America and in Europe. Asia can compete effectively by investing wisely in specific collaborative projects.
The MOU between ASIAA and NAOJ was signed in Oct 2008 to join the HSC project, by helping to construct specific parts of the instrument. The experience gained through the TAOS and WIRCam projects will be applied. The HSC is planned to be finished by 2012. Meanwhile, the MOU also aims for a long term collaboration with Subaru telescope. The official partners of HSC now include NAOJ, University of Princeton and ASIAA. The three sides will work together on the HSC survey plan.
Specifications of HSC
|Field of View||1.5 degree diameter||Vignetting allowed up to 25 % at the edge
Dead area (CCD gap) fraction ≦5 %
|Instrument PSF size||≦0”.3 for r’, i’
≦0”.4 for g’, Y
|Pixel scale||≦0”.2 /pix|
|System Throughput||≦50 % for g’
≦65 % for r’
≦65 % for i’
≦40 % for z’
|Minimum Shutter Speed||3 sec (1 sec goal)||Time accuracy ≦1 %|
|Min. interval of Exposures||20 sec (15 sec goal)||Including CCD readout and wipe pointing change|
For more details of HSC, please see the presentation file from Satoshi Miyazaki. » Download PDF file.