  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'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'=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'=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}~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 <= 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~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.
