M 51

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Observation place
New Mexico


TelescopePlanewave 431mm – 17″, 1940mm FL, f/4,5 with focal reducer
MountPlanewave Ascension 200HR (FLI)
Imaging cameraMicroline PL6303E (FLI) - regulated at -25o Celsius
Image typeL (RGB) (Vs for synghetic green)
ExhibitionLuminance (9 x 10 'bin 1 × 1), R and B (4 x 3' bin 2 × 2 each)
PretreatmentMaxim DL
TreatmentPhotoshop and PixInsight
Specific treatmentCreate a synthetic green image

Object description

Object typeRegular (M51) and irregular (NGC5195) spiral galaxies called "The Tourbillon Galaxy"
ConstellationHunting dogs
Visual magnitude8,4
Distance27,4 million light years (M51)
Diameter100000 light years
Dimension seen from Earth11,2 x 6,9 arcminutes (M51 and NGC5195)  
M51 and NGC5195, nicknamed the Tourbillon Galaxy, are a pair of galaxies located in the constellation Chiens de Chasse. They are located at a distance of about 27,4 million light years from the earth. They are seen from the front. The diameter of the galaxy M51 is 100000 light-years, comparable to that of our Milky Way. It also has an equivalent mass of 160 billion times that of the Sun.  

Currently, the two galaxies are on the verge of merging into a single galaxy. They started to bond together. See, in the photo, the bridge of matter that connects the two galaxies. This merger will last several thousand years.  

To observe the Tourbillon galaxy, you must choose a site without light pollution. Under the refracting telescope, the two galaxies appear as two spots of low light: they are the nuclei of the two galaxies. It is only with a 150 mm diameter telescope that we begin to detect the spiral arms of the main galaxy. With a 300mm telescope, we can see the bridge of matter that connects the two galaxies.  

In my image, which was taken in a sky without light pollution, we can appreciate the great beauty of these two galaxies, which is presented above all in blue tones. We can also observe a veil of very low light dust that surrounds the two galaxies. It is not easy to bring it out.  

There are several other galaxies around the Whirlpool galaxy. Here is my image with a larger field of view:

With the PixInsight software, I made an annotation of these galaxies:

So there are 9 galaxies in total in this image which has a field of view of about 40 'x 30' of arc (the Moon at about 30 'of arc), which is a very small portion of the night sky! In addition, all of these galaxies each have billions of stars! Several appear small in the image for the reason that they are very distant. For example, galaxy IC4278 is approximately 230 million light years from Earth, compared to the main galaxy M51 which is only 27,4 million light years away. Of course, these distances are small compared to our Universe, which has been expanding for 13,73 billion light years!
Richard Beauregard
Sky Astro - CCD
My impression "We cannot be alone in this gigantic universe"