Satellite contemplating observatory contemplating satellite
I fairly often take photos of friends who are taking photos; sometimes they're even taking photos of me taking photos of them.
But when you've got big pieces of equipment that are capable of taking photos, then they can take photos of each other without any evidence of humans being involved.
Case in point: the GeoEye-1 satellite took a photo of Arecibo Observatory, which appears to be pointing back up at the satellite.
Thanks to T C for pointing out the nifty Flash gallery of satellite photos where I found this. (The Arecibo one is #17 in that gallery; the Burning Man one I linked to previously is #3.)