NGC 206 - Star Cluster in Andromeda Galaxy
It is one of the largest star forming regions known in our local group of galaxies, much larger than the clusters of stars in the disk of our Milky Way galaxy. It contains more than 300 stars brighter than Mb=-3.6. It was originally identified by Edwin Hubble as a star cluster but today, due to its size, it is classified as an OB association. Usually OB associations contain 10–100 massive stars of spectral class O and B. In addition, these associations also contain hundreds or thousands of low- and intermediate-mass stars. In this case, NGC 206 contains more than 300 of such very bright stars.
NGC 206 is located in a spiral arm of the Andromeda Galaxy, in a zone free of neutral hydrogen and has a double structure, with one region that has an age of around 10 million years and includes several HII regions in one of its borders and other with an age of between 40 million years and 50 million years that includes a number of cepheids. Both parts are separated by a band of interstellar dust and include hundreds of stars of spectral type O and B.
The bright, blue stars of NGC 206 indicate its youth. Its youngest massive stars are less than 10 million years old. Much larger than the clusters of young stars in the disk of our Milky Way galaxy known as open or galactic clusters, NGC 206 spans about 4,000 light-years. That's comparable in size to the giant stellar nurseries NGC 604 in nearby spiral M33 and the Tarantula Nebula, in the Large Magellanic Cloud. Among those stars are several Cepheids variable stars: very luminous variable stars with a strong direct relationship between their variable’s luminosity and pulsation period. That secures their status as important standard candles for establishing the Galactic and extragalactic distance scales. So, studying Cepheids in NGC 206 can provide a way to accurately measure the distance to the cluster and the Andromeda galaxy. That way we may also have a proper scale for the Universe as such.
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NGC206 is a great object for long focal lenght imaging. It's trully incredible, how many fine details of the Andromeda galaxy can be seen in this image. Rich, massive dust and star clouds filling whole field of view. Additionally I have added annotation for Globular Clusters that reside inside of the galaxy and visible in my field of view. They marked with G letter on annotated version of the image.
I have been hunting this object for two months. Well, mostly because I can image only 2 nights in a month and first time I imaged it in early October 2013, I was without cooling. After 15 minutes exosure EXIF temperature reported were from 32° to 35°C. Getting back home I found that the whole data were unusable. That day I decided that I have to build the cooler box for my camera and get back to this object.
And so I did. During the next month I managed to build it, you can find it in DIY section and results were simply amazing!!! I couldn't believe my own eyes, that after 15 minutes of exposure, the temperature reported by EXIF were only 5°C. Unfortunately, only 18 frames made it and were worth of stacking. Next time I could get back to the field in February 2014, so I missed the opportunity to get more data and decided to process what I already have.
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Technical Info:
Optics : Meade 10" + CCDT67 @ F8 @ 2020 mm
Camera : Canon T3i (600D) Baader Mod
Mount : NEQ-6 Pro (Self Hypertuned/Belt Mod)
Guiding: Telescope Service OAG9 + SX Lodestar
Acquisition : BackyardEOS 3.0.3
Exposure : 18 x 900 sec @ ISO1600 - 4.5 Hours
Stacking : PixInsight 1.8
Processing : PixInsight 1.8
