FreeAstro

Occultation of star TYC 0075-00715-1 by asteroid 41 Daphne, on Jan, 17 2016. Acquired by the TFG team, processed by V. Hourdin and C. Richard.

Several 4 seconds videos were taken at one minute interval before and after the event, and a long video for the main event. No preprocessing data was acquired, only raw grabs from analog videos with GPS time inscruster adding even more noise. See an extract of the raw video or as an image on the right, extracted from the first video.

Many new features of Siril have been created in order to process this particular image and are now available for everybody. The complete steps required are:

• automatic sum stacking of all sequences found in a directory, in this case AVI films, with no registration and no preprocessing
• adding a command for easy selection of a large range of images inside a sequence, to stack the two occultation frames
• sequence crop for all stacked files, to remove the time insert
• creating a master dark frame from a single real image modified with extreme scaling to filter hot pixels and application of this frame with the cosmetic filter for pre-processing
• one-star registration and manual registration for a few frames
• sequence application of the banding noise removal was made possible
• sequence export with registration data and frame normalization into a GIF file.