NGC 7217

About image
NGC 7217 is a spiral galaxy in Pegasus constellation, about 50 million light years away.
Its main feature is the presence of several concentric rings of stars in its nucleus: three are the main ones, the outermost of which is the most rich in gas and the one that hosts the largest number of episodes of star formation, to which add more, more interiors to the first three, discovered by the Hubble Space Telescope.
Another noteworthy feature is the presence of a certain number of stars rotating around the nucleus of the galaxy in the opposite direction with respect to most of the others, and of two distinct star populations: one of intermediate age in the innermost regions, a younger one but poorer than metals to the outside.
These characteristics are believed to have been caused by fusion with another galaxy and indeed some computer simulations show that NGC 7217 could be a large lenticular galaxy, which merged with one or two smaller gas-rich, becoming the galaxy to spiral we see today.

Technical data
Optic            Celestron C9.25 Edge HD f/10
Mount          Losmandy G11 with Ovision worm and FS2
Camera           Atik 4000 with Starlight Xpress filter wheel 5 positions
Filters        Baader 50.8 unmounted
Guiding system      OAG LB Astro Proxima with Lodestar
Exposure details    L 24x600" bin1 -20C
            R 7x420" bin2 -20C
            G 7x420" bin2 -20C
            B 7x420" bin2 -20C
Total integration    6.5h
Acquisition       Maxim, PHD2
Processing       Maxim, Photoshop CS5
SQM-L         21.04   
Location        Pian dell'Armà (Italy)
Date            11 August 2015, 12 August 2015

© Roberto Marinoni 2019 - All rights reserved