NGC3079 and the lensed twin quasar QSO 0957+561

About the Object

NGC 3079 is a close to edge-on barred spiral galaxy in the constellation of Ursa Major. Its distance is about 50 Million light-years. According to SIMBAD it is a Seyfert II galaxy, ie it exhibits nuclear activity.

About 10 arcmin north of NGC3079 (at about 1 o'clock see also annotated image in revision B) is the famous Twin Quasar QSO 0957+561, aka PGC 2518326, the first gravitationally lensed QSO discovered in 1979. QSO 0957+561 is located at a redshift of about 1.41, i.e. 8.7 billion light-years away - quite a deep peek from my backyard …!

Lensed QSO are of increasing interest as they provide an independent method to measure the Hubble constant and thus may eventually help explaining the tension between local measurements (based on Cepheids etc) and thus derived from the Cosmic Microwave Background and large structures in the cosmic web.

Observation Notes

Data were then on 2026 January 21 and 22.

Technical Details

View the full-resolution image together with complete acquisition and processing details on AstroBin.