TrevorW
24-12-2009, 11:14 AM
Target: NGC2808 Globular Cluster Bennett 41
Camera: Canon 350d modified, Astronomik CLS clip filter
Exposure Capture: DLSR Focus,
Scope: GSO CF RC200
EFR: f/8
Mount: EQ6 Pro
Exposure Setting: Prime focus, ISO800 ICNR off Custom WB
Exposures: 21 x 60s, 10 x 180s, 9 x 330s, 2 x 600s lights taken between 8:00 and 1:00am 23-24/12/09
Seeing: first quarter moon, slight wind
Guiding: Orion Starshoot Autoguider using PHD with ED80
Focus: DSLR Focus Bahitov mask
Stacking: DSS with corresponding darks and flats
Processing: PS CS3 curves, levels, colour , PixInsight for DBE, MaxDL for background flatten gradient removal
Constellation Carina
Right ascension 9h 12m 2.6s Declination -64° 51′ 46.2″ Distance Approximately 30,000 light-years (9,000 parsecs) 24 light-years or 8 parsecs wide. Apparent magnitude (V) 7.8
NGC 2808 is a globular cluster in the constellation Carina. The cluster belongs to the Milky Way, and is one of our home galaxy's most massive clusters, containing more than a million stars. It is estimated to be 12.5-billion years old.
Star Generations
It had been thought that NGC 2808 - like typical globular clusters - contains only one generation of stars \formed simultaneously from the same material. In 2007, a team of astronomers led by G. Piotto of the University of Padua in Italy investigated Hubble Space Telescope images of NGC 2808 taken in 2005 and 2006 with Hubble's Advanced Camera for Surveys. Unexpectedly, they found that this cluster is composed of three generations of stars, all born within 200 million years of the formation of the cluster. Astronomers have argued that globular clusters can produce only one generation of stars, because the radiation from first generation stars would drive the residual gas not consumed in the first star generation phase out of the cluster. However, the great mass of a cluster such as NGC 2808 may suffice to gravitationally counteract the loss of gaseous matter. Thus, a second and a third generation of stars may form.An alternative explanation for the three star generations of NGC 2808 is that it may actually be the remnant of a dwarf galaxy that collided with the Milky Way.
Camera: Canon 350d modified, Astronomik CLS clip filter
Exposure Capture: DLSR Focus,
Scope: GSO CF RC200
EFR: f/8
Mount: EQ6 Pro
Exposure Setting: Prime focus, ISO800 ICNR off Custom WB
Exposures: 21 x 60s, 10 x 180s, 9 x 330s, 2 x 600s lights taken between 8:00 and 1:00am 23-24/12/09
Seeing: first quarter moon, slight wind
Guiding: Orion Starshoot Autoguider using PHD with ED80
Focus: DSLR Focus Bahitov mask
Stacking: DSS with corresponding darks and flats
Processing: PS CS3 curves, levels, colour , PixInsight for DBE, MaxDL for background flatten gradient removal
Constellation Carina
Right ascension 9h 12m 2.6s Declination -64° 51′ 46.2″ Distance Approximately 30,000 light-years (9,000 parsecs) 24 light-years or 8 parsecs wide. Apparent magnitude (V) 7.8
NGC 2808 is a globular cluster in the constellation Carina. The cluster belongs to the Milky Way, and is one of our home galaxy's most massive clusters, containing more than a million stars. It is estimated to be 12.5-billion years old.
Star Generations
It had been thought that NGC 2808 - like typical globular clusters - contains only one generation of stars \formed simultaneously from the same material. In 2007, a team of astronomers led by G. Piotto of the University of Padua in Italy investigated Hubble Space Telescope images of NGC 2808 taken in 2005 and 2006 with Hubble's Advanced Camera for Surveys. Unexpectedly, they found that this cluster is composed of three generations of stars, all born within 200 million years of the formation of the cluster. Astronomers have argued that globular clusters can produce only one generation of stars, because the radiation from first generation stars would drive the residual gas not consumed in the first star generation phase out of the cluster. However, the great mass of a cluster such as NGC 2808 may suffice to gravitationally counteract the loss of gaseous matter. Thus, a second and a third generation of stars may form.An alternative explanation for the three star generations of NGC 2808 is that it may actually be the remnant of a dwarf galaxy that collided with the Milky Way.