The Oxford Dartmouth Thirty Degree Survey ( ODTS ) is a deep , wide , multi-band imaging survey designed to cover a total of 30 square degrees in BVRi ^ { \prime } Z , with a subset of U and K band data , in four separate fields of 5-10 deg ^ { 2 } centred at 00:18:24 +34:52 , 09:09:45 +40:50 , 13:40:00 +02:30 and 16:39:30 +45:24 .
Observations have been made using the Wide Field Camera on the 2.5-m Isaac Newton Telescope in La Palma to average limiting depths ( 5 \sigma Vega , aperture magnitudes ) of U =24.8 , B = 25.6 , V = 25.0 , R = 24.6 , and i ^ { \prime } = 23.5 , with observations taken in ideal conditions reaching the target depths of U =25.3 , B = 26.2 , V = 25.7 , R =25.4 , and i ^ { \prime } = 24.6 .
The INT Z band data was found to be severely effected by fringing and , consequently , is now being obtained at the MDM observatory in Arizona .
A complementary K -band survey has also been carried out at MDM , reaching an average depth of K _ { 5 \sigma } \approx 18.5 .
At present , approximately 23 deg ^ { 2 } of the ODTS have been observed , with 3.5 deg ^ { 2 } of the K band survey completed .
This paper details the survey goals , field selection , observation strategy and data reduction procedure , focusing on the photometric calibration and catalogue construction .
Preliminary photometric redshifts have been obtained for a subsample of the objects with R \leq 23 .
These results are presented alongside a brief description of the photometric redshift determination technique used .
The median redshift of the survey is estimated to be z \approx 0.7 from a combination of the ODTS photometric redshifts and comparison with the redshift distributions of other surveys .
Finally , galaxy number counts for the ODTS are presented which are found to be in excellent agreement with previous studies .