Re: Can you take 3-D astronomical images?

Yes and no....but more no than yes!

You are right that taking images of astronomical objects when the Earth is at opposite sides of the Sun (summer and winter, say) should give slightly different views due to nearer objects seeming to move with respect to more distant objects. In principle this gives 3D information, and indeed is the basis of the "parallax" method for determining the distances to stars.

Unfortunately, as you guessed, even the nearest stars are too far away for this method to be used to create stereoscopic images. In fact, it wasn't until the 1830s that the first parallaxes were measured at all, and in every case, for stars beyond the Sun, parallaxes were found to be less than one second of arc (about the size of a penny viewed from a distance of 2 miles).

However, given that astronomers can now measure (to reasonable accuracy) the distances to many astronomical objects, it is, of course, possible to create simulated stereoscopic images of regions of space. This has been done, for instance, for the distribution of galaxies in space based on various surveys. It has also been done using the results from ESAs Hipparcos satellite which, to date, is the source of by far the largest catalogue of accurate stellar parallaxes. See the Hipparcos web site for more details.