We perform a detailed photometric study of the stellar populations in a Galactic Field at l = 232 ^ { o } , b = -6 ^ { o } in the Canis Major ( CMa ) constellation .
We present the first U,B,V,I photometry of the old open cluster Auner 1 and determine it to be \approx 3.25 Gyr old and to lie at 8.9 kpc from the Sun .
In the background of the cluster , at more than 9 kpc , we detect a young population most probably associated to the Norma Cygnus spiral arm .
Furthermore , we detect the signature of an older population and identify its Turn Off and Red Giant Branch .
This population is found to have a mean age of 7 Gyrs and a mean metallicity of Z = 0.006 .
We reconstruct the geometry of the stellar distribution and argue that this older population - often associated to the Canis Major galaxy - belongs in fact to the warped old thin/thick disk component along this line of sight .