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The Twin Quasar QSO 0957+561AB


Dr. Gerold Holtkamp, 2021.03.06


The moon had already risen at 22:30 MEZ on March 2, 2021, but was still low on the horizon. With 83% disk lit, it would soon become a fairly bright "lantern". However, the author was not deterred by this and nevertheless directed the telescope of the observatory of the Natural Science Association Osnabrück to the so-called twin quasar QSO 0957+561AB. What we see on earth are two images of the same quasar produced by a so-called gravitational lens (-more information here-). With a brightness of just 16.7 or 16.5 mag of the two components and a distance of approx. 6'', a telescope with a mirror diameter of 60 cm is the right choice. The observation object was high - almost at the zenith - so that the telescope and dome slit had to "dislocate" quite a bit.


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Twin quasar QSO 0957+561AB


The visual separation of the two components has been successful. If these components can be separated, then perhaps the so-called Einstein cross – four pictures oft he same quasar separated 1.6''' should also be separable. A nice challenge ....


Technical data:

Telescope: Cassegrain 60 cm mirror diameter, 745 cm focal length

Filter: Hutech IDAS LPD2

Camera: Canon 6D, ISO 3200

Shots: 13×300 s, dark, flats, flat darks

Processing: DSS, fitswork