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update: I still haven't been able to get my hands on the Icarus paper linked below (I'll try other libraries) but these are newer and quite interesting!:


How did Arecibo make radar images of ice on Mercury's poles?

  1. How were observations of the poles of Mercury geometrically possible from Earth?
  2. How was "high-resolution (1.5-km) imaging" possible from Earth?
  3. How was ice identified and imaged?

From Chapter 6; Planetary Radar Astronomy in A Strategy for Active Remote Sensing Amid Increased Demand for Radio Spectrum (2015):

Radar observations from Earth continue to provide new information about the terrestrial planets and the Moon despite the many spacecraft flybys, orbiters, and landers. The unique radar back-scattering properties of water ice led to the discovery by ground-based radar of ice deposits in the permanently shadowed portions of impact craters at Mercury’s poles. High-resolution (1.5 km) radar imaging of these deposits has mapped out their distribution with high precision9 (Figure 6.9).

9Radar imagery of Mercury’s putative polar ice: 1999–2005 Arecibo results Icarus, 211, (1) January 2011, pp 37-50

FIGURE 6.9 Arecibo radar image of the distribution of ice deposits at the north pole of Mercury...

FIGURE 6.9 Arecibo radar image of the distribution of ice deposits at the north pole of Mercury (yellow), superimposed on a mosaic of Messenger orbiter images showing the coincidence of the ice deposits with the shadowed portions of impact craters. SOURCE: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

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  • $\begingroup$ I really don't understand your main question. Are you asking how the radiotelescope works, or which method is used for radar-imaging ? $\endgroup$ – Cornelisinspace Jul 13 at 13:03
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    $\begingroup$ From Earth we see the side of Mercury, but these images look like they are taken "top-down". I'm trying to figure out geometrically how such detailed images can be made of the polar areas which are really viewed from the side, especially how details at the bottoms of craters at the poles can be investigate from Earth. $\endgroup$ – uhoh Jul 13 at 13:53
  • $\begingroup$ I think details at the bottoms of the craters at the poles are not from Arecibo, but it's amazing for me too that the distribution is that detailed. Could the inclination of Mercury's orbit help in explaining ? $\endgroup$ – Cornelisinspace Jul 13 at 14:15
  • $\begingroup$ @Cornelisinspace Oh, I see what you mean; I think that you have solved my problem! I think you can just write up the explanation as an answer. I totally missed that. $\endgroup$ – uhoh Jul 13 at 14:54

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