By now we are all familiar with the official image of the black hole in M87:

enter image description here

Now, in the universe, as far as I know, there is no up and down, nor left and right. All is relative. Hence my question: why the particular chosen angle of the image released? Why not instead release the image as, for example, below? Which is the point of reference chosen in the original image? Is it of any particular significance?

enter image description here


1 Answer 1


North is to the top and East is to the left. I believe it is a standard image in celestial coordinates.

It is important to standardise so that the image can be compared with large scale features like the M87 jet.

  • 1
    $\begingroup$ Sorry, are you saying that if I stand looking at the north pole, and then look "up" at the black hole exactly when it is in my celestial meridian, it will look like in the picture? $\endgroup$
    – luchonacho
    Apr 12, 2019 at 12:51
  • 2
    $\begingroup$ @luchonacho That is the usual case for images presented in celestial coordinates, yes. $\endgroup$
    – ProfRob
    Apr 12, 2019 at 13:47

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