Traditional method

The traditional method from now on of detection consists of an observation repeated twice with 3 or 4 weeks of intervals of the same field. The first period will be called reference period, the second period of research. Figure 7.6 presents the strategy of détéction.

Figure 7.6: Strategy of search for supernovæ of the type Ia loitaines in filter I.

In the continuation, we will detail the various stages of the chain of detection which, of the rough images provided by the telescope, allow detection.

Initially, we detail the stages of pretreatment which mainly consist in correcting the images for the various signatures of the camera and to label the defects more shouting in order to reject them thereafter. The second stage allows, as from the various periods of observations, to build two times the major images. Those are then compared, brought to the same resolution and finally are withdrawn. The last stage consists in detecting the residual sources on the subtraction among which the supernovæ are.