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 M31 - The Great Andromeda Galaxy - HII Area Enhanced 
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About:
The most distant object easily visible to the eye is M31, the great Andromeda Galaxy some two and a half million light-years away. But without a telescope, even this immense spiral galaxy - spanning over 200,000 light years - appears as a faint, nebulous cloud in the constellation Andromeda. In contrast, details of a bright yellow nucleus and dark winding dust lanes, are revealed in this digital telescopic image. In this image also a data recording emission from hydrogen atoms, shows off the reddish star-forming regions dotting gorgeous blue spiral arms and young star clusters. While even casual skygazers are now inspired by the knowledge that there are many distant galaxies like M31, astronomers seriously debated this fundamental concept in the 20th century. Were these "spiral nebulae" simply outlying components of our own Milky Way Galaxy or were they instead "island universes" -- distant systems of stars comparable to the Milky Way itself? This question was central to the famous Shapley-Curtis debate of 1920, which was later resolved by observations of M31 in favour of Andromeda, island universe. [Text from APOD]



Pubblications "Flickr" Explore - December 6th, 2014
Optics: Takahashi FSQ-106EDXIII F/3.6 383mm. - APO Refractor
Mount: AP Mach1 GTO
Camera: QSI-683WSG
Filters: Astrodon E Series Gen II LRGB 31mm - 5nm Ha
Guiding Systems: SX Lodestar
Dates/Times: 9/12 October 2012 - 20 November 2014
Location: Castelmagno - Cuneo / "Val Troncea" - Pragelato - Italy
Exposure Details: L:H:R:G:B => 220:180:120:100:120 = > (22x10):(12x15):(12x10):(10x10):(12x10) All Bin1 [num x minutes]
Cooling Details: -25 °C
Acquisition: Maxim DL/CCD, Perseus, Voyager
Processing: CCDStack2+, PixInsight, PS CS5
Mean FWHM: 1.57/1.98
SQM-L: 21.35/ 21.33