3 Image reduction

Our image contains, in pixel size, a region of $3150({\rm SN}) \times 3200({\rm EW})$ of SMC. The scanning pixel size of a Super-COSMOS measuring machine is 10 $\mu \mbox{m}$and the plate scale is $67.11\;\mbox{arcsec/mm}$. Our image with center $\mbox{RA}_{2000}=1^{{\rm h}}16^{{\rm m}}$ and $\mbox{DEC}_{2000}=-73^\circ 20'$ contains a region of $35.2\;\mbox{arcmin}({\rm SN})\times 35.8\;\mbox{arcmin}({\rm EW})$ of SMC (Fig. 1).

The saturation limit of the plate has a density value of 2.2. This means that for the pixels having negative decimal logarithm of density value greater than 2.2, we have non-linear distortion of density-intensity plate diagram. The magnitude limit for classifying the spectra of our plate is m_B=18.5.

Figure 1: Super-COSMOS negative image of a region $35.2\;\mbox{arcmin}({\rm SN})\times 35.8\;\mbox{arcmin}({\rm EW})$ of SMC