M 31

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Observation place
New Mexico


TelescopeTakahashi FSQ 106ED, 106mm, f / 5
MountParamount ME
Imaging cameraSBIG STL 11000 regulated at -15o Celsius
Image typeL (RGB)
ExhibitionLuminance (12 x 5 'bin 1 × 1), RGB (3 x 2' bin 2 × 2 each)
TreatmentPhotoshop and PixInsight

Object description

Object typeSpiral galaxy "the great Andromeda galaxy"
Visual magnitude3,4
Distance2,9 million light years
Diameter250000 light years
Dimension seen from Earth178 x 40 arc minutes  
M31 is the brightest galaxy in the northern sky. It is the largest galaxy in the Local Group (our Milky Way being the second). It is the closest to our galaxy. Its disk is twice as large as our galaxy. It is easily visible to the naked eye or with binoculars.

Despite the extensive studies of which it is the object, the Andromeda galaxy has not yet revealed all its secrets. It would not be the typical spiral galaxy it appears to be: for example, despite its considerable size, it appears less massive than the Milky Way, and its halo of dark matter is diluted. Nonetheless, astrophysicists have calculated that its central black hole is 30 million solar masses, ten times that of the Milky Way. The enormous mass of this black hole is surprising, because, as a rule, the black hole of a galaxy is supposed to mirror the mass of its parent galaxy. In addition, analyzes in different wavelengths revealed a discontinuity of the galactic disk, which would be due to a collision with one of its satellite galaxies in recent millions of years.

M31 and our Milky Way are approaching each other at a speed of 100 to 140 km per second: they should collide and merge together within 5 billion years. In the meantime, we have plenty of time to live our lives and allow our children, grandchildren… to enjoy our beautiful, comfortable planet, on condition of course that we protect it well.
We can see on the photo towards the bottom right the galaxy M110 which has a magnitude of 8,1 and an apparent dimension of 17 'x 10'. We also see the galaxy M32, the white point which is almost stuck on the arm of the galaxy at the top slightly to the left. It also has a magnitude of 8,1 with a visible dimension of 8 'x 6'. So we see 3 galaxies in this photo! One can appreciate the grandeur and even the enormity of the Andromeda galaxy compared to the other two.
Richard Beauregard
Sky Astro - CCD
My impression "We cannot be alone in this gigantic universe"