quasar175Calar Alto participates in a multi-observatory effort to study the most luminous quasar ever observed. The object, radio quasar 3C 454.3 in the constellation Pegasus, experienced during 2005 a strong optical outburst  that made it observable even with amateur instrumentation (reaching R = 12 mag). According to the WEBT team, "this ourburst peak likely represents the most luminous quasar state ever observed". The same team quantified the maximum luminosity of this object as MB = -31.4 mag. This means that, at its maximum and when observed in blue light, 3C 454.3 was as bright as 550 billions of suns put together...

horse_head175The famous HorseHead Nebula in Orion (also known as Barnard 33) as seen from Calar Alto. This unusual shaped nebula was first spotted in 1888 on a photographic plate taken at the Harvard College Observatory. The nebula is located just below Alnitak, the easternmost star of Orion's Belt, lies at a distance of about 1500 light-years from Earth, and is approximately 3.5 light-years wide. The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. The darkness of the Horsehead is caused by tiny...