The Deep and Wide fields location has been decided by the Steering Group after extensive discussions with the Canadian and French scientific communities.

The constraints were:

• Low dust extinction
• Right ascension distribution over the year
• Visibility from the VLT
• Other surveys coverage

The following plot points on a full sky map the position of the Deep and Wide fields, as well as the ecliptic plane (dense red dotted line, the other dotted line maps the Galactic plane) covered partially by the Very Wide survey. "NGP" stands for North Galactic Pole.

The four Deep and Wide fields are spread across the year and their peak of visibility match roughly the following periods:

The following table gives the coordinates of the center of the Deep and Wide fields, their size, other surveys it relates to, and an extinction map from the region.

CFHTLS Deep fields
D1 - 1 x 1 square degree 02:25:59 -04:29:40 2000 In W1
D2 - 1 x 1 square degree 10:00:28 02:12:30 2000 On the COSMOS/ACS survey field
D3 - 1 x 1 square degree 14:19:27 +52:40:56 2000 In W3
D4 - 1 x 1 square degree 22:15:31 -17:43:56 2000 Around the quasar LBQS2212-17
CFHTLS Wide fields
W1 - 9 x 8 square degrees 02:18:00 -07:00:00 2000 On the XMM LSS field
W2 - 5 x 5 square degrees 08:57:49 -03:19:00 2000
W3 - 7 x 7 square degrees 14:17:54 +54:30:31 2000 On the Groth Strip
W4 - 25 square degrees in a SE-NW oriented stripe 22:13:18 +01:19:00 2000 On the VVDS 22h & UKIDSS DXS fields
Click on the images to get more information on the fields (extinction - bright stars) (University of Toronto - SNLS Team)