The Deepsky images are all made with the 62cm f/15 telescope of the observatoire de Saint Véran. To enlarge to field of view, we equipped the telescope with a focal reducer, to obtain a focal length of 1.8m (instead of 9m) or a 62cm f/3 telescope.

The exposure time is large (more than 10 minutes) to reduce noise. We always combine several images of 1 or 2 minutes to correct the images for faults which will not be corrected by the dark-frame or flat-fields (such as for cosmic rays - which appear quite frequently at this altitude - and for dark pixels on the camera).

The pre-processing step is a bias, dark-frame and a flat-field correction and a combination of the raw images. The further processing depends on the image, we will use logarithmic visualisation, trichrometry and sometimes deconvolution algorithms such as Richardson-Lucy.