The Wide Synoptic and the Deep Synoptic fields location has been decided by the Steering Group after extensive discussions with the community of registered users, and among the Steering Group itself.

The constraints were:

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

The following plot points the position of the Deep and Wide fields as well as the ecliptic plane on a full sky map:

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

• D1/W1 = fall [RA/DEC: ~ 02hr/-04deg]
• D2/W2 = winter [RA/DEC: ~ 10hr/+02deg]
• D3/W3 = spring [RA/DEC: ~ 14hr/+52deg]
• D4/W4 = summer [RA/DEC: ~ 22hr/-17deg]

The following table gives the coordinates of the center of the Deep and Wide fields, their size, and the principal survey it relates to:

CFHTLS Deep Synoptic Survey Fields
D1 - 1o x 1o 02:26:00 -04:30:00 2000 In W1
D2 - 1o x 1o 10:00:29 02:12:21 2000 On the COSMOS/ACS survey field
D3 - 1o x 1o 14:17:54 +52:30:31 2000 In W3
D4 - 1o x 1o 22:15:31 -17:44:05 2000 Around the quasar LBQS2212-17
CFHTLS Wide Synoptic Survey Fields
W1 - 8o x 9o 02:18:00 -07:00:00 2000 On the XMM LSS field
W2 - 7o x 7o 08:54:00 -04:15:00 2000
W3 - 7o x 7o 14:17:54 +54:30:31 2000 On the Groth Strip
W4 - 4o x 4o 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)