Or is it just historical convention? I know that within research circles, it is common to also use the term "radio image". I am mainly wondering whether the term originally comes from wanting to differentiate between an "actual" image and something that is more of a representation.

I know that if we want to be really precise, even optical images are representations, but still I feel there is a big difference between those and imaging wavelengths that we cannot see at all.

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    $\begingroup$ There is no convention that they should be called maps. Do a google search on "radio images astronomy" and see what comes up. $\endgroup$
    – ProfRob
    Commented Mar 7 at 11:33
  • $\begingroup$ Perhaps because "a map is not the territory"? For example, see the famous Magritte painting of a pipe that declares, in French, that "this is not a pipe." Some astronomers are quite compelled by the map-territory relation. $\endgroup$ Commented Mar 7 at 11:56
  • $\begingroup$ @DavidHammen very interesting analogy! I think in Physics/Astronomy in general, the distinction between the description/depiction of something and "reality" (whatever that might be) is really interesting. $\endgroup$
    – Loika
    Commented Mar 7 at 12:03

1 Answer 1


There is no distinction.

No matter which wavelength regime you consider, "image" is an adequate and frequently used description. Also for radio, microwaves, sub-mm, IR, UV, and X-rays.

The reason that we also use the word "map" is that very often we're interested not only in the "full" picture, but in analyzing differences across the image, e.g. looking a the morphology of a galaxy, the distribution of stars, or the extinction at various locations in a nebula. The image can be considered a map of the object, just like a land map is a chart of the differences in a landscape.


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