I-filter i'-filter z'-filter

Fringe frames

Fringe frames built from 120s dithered exposures of relatively empty sky regions. For each filter 20 images were combined with stars removed by median filtering.

 

I-filter i'-filter z'-filter

Example of fringes removal: ESO 510-20

Image of galaxy ESO 510-20 (The Dentist's Chair) taken with SOI in I, i' and z' filters. The galaxy was imaged on the second CCD, where the fringes effect is stronger. The shadow from the guider probe and scattered light from the bright guide-star are seen in the first CCD. Exposure times were: 8min. (I) and 15min. (i' and z').

 

I-filter i'-filter z'-filter

Corrected images

Images of the galaxy after correction for fringes. The corrected images are the result of subtracting scaled fringe frames from the galaxy's images.