trevorw
April 10th, 2010, 03:33 PM
Target: NGC2808 Globular Cluster in Carina
Camera: QHY 8 OSC CCD camera IR/UV filter
Exposure Capture: Maxim DL
Scope: GSO CF RC200
EFR: f/8
Mount: EQ6 Pro
Exposure Setting: Prime focus
Exposures: 10x6min taken 9th April 2010
Seeing: moon not yet risen
Guiding: Orion Starshoot Autoguider using PHD
Focus: Maxim, Bahitov mask
Stacking: DSS 3 darks 10 flats, 10 bias applied
Processing: CS3 levels curves shadow highlights colour balance, Carboni Actions noise reduction, Gradient Exterminator
Info: Situated in the Carina
Observation data (J2000 epoch) Constellation Carina Right ascension 9h 12m 2.6s[1] Declination -64° 51′ 46.2″ Apparent magnitude (V) 7.8)
NGC 2808 belongs to the Milky Way, and is one of our home galaxy's most massive globular 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 GC’s, contains only one generation of stars formed simultaneously from the same material. In 2007, a team of astronomers led by Giampaolo 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.[2]
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: QHY 8 OSC CCD camera IR/UV filter
Exposure Capture: Maxim DL
Scope: GSO CF RC200
EFR: f/8
Mount: EQ6 Pro
Exposure Setting: Prime focus
Exposures: 10x6min taken 9th April 2010
Seeing: moon not yet risen
Guiding: Orion Starshoot Autoguider using PHD
Focus: Maxim, Bahitov mask
Stacking: DSS 3 darks 10 flats, 10 bias applied
Processing: CS3 levels curves shadow highlights colour balance, Carboni Actions noise reduction, Gradient Exterminator
Info: Situated in the Carina
Observation data (J2000 epoch) Constellation Carina Right ascension 9h 12m 2.6s[1] Declination -64° 51′ 46.2″ Apparent magnitude (V) 7.8)
NGC 2808 belongs to the Milky Way, and is one of our home galaxy's most massive globular 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 GC’s, contains only one generation of stars formed simultaneously from the same material. In 2007, a team of astronomers led by Giampaolo 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.[2]
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.