Re: [Fwd: [cfhtls] CFHT Large Program Campaign [2008B-2012B] now open!]

The basic idea for a wide-wide survey would place about 5000 square
degrees on the existing SDSS and UKIDSS fields. SDSS would give a
baseline calibration (although we could do better if we added in
synoptic component of our own) and astrometry. UKIDSS would give the NIR
(agreements woul probably need to be worked out) and it is already well
underway. Wircam does not appear to be competitive for the wide field
work. It would be extremely valuable if all ugriz could be done,
although it would be important to have a realistic plans for u*
(requires truly dark skies and good IQ) and z' (low QE detectors and
still has fringing issues). With all 5 filters (ambitious, but that is
the whole idea) the pace will be about 2 sq degrees/hour, which means
about 2500 hours. That is a lot of time in 9 semesters. However, that
is the value of the Letter of Intent process. There can be formal
feedback on the idea.

The BAO idea can be one driver, but it should not stand alone. This is
highly competitive field and as one looks into a purely photometric
approach one realizes that this will require considerable care. I would
prefer a wide ranging science case like SDSS. Everything from metal poor
stars to galactic structure to the z~0 to 1 universe to the z~7+
universe, in galaxies, dark matter, IGM. Aside from "instant science"
there will be long term uses for complementarity to other telescopes,
everything form JWST to the ELTs. It will be important to pick the
fields to ensure that Herschel, etc, fields are covered. But, 5000 sq
degrees helps guarantee that this gets done.

Getting the data reduced to the highest possible standard is a
significant challenge. The CFHT community has a lot of experience but
will need the people and computing to be put in place to make sure that
this gets done quickly.