Complete newbie on the topic of GL but I find it very interesting.
Q: We seem to want to use our sun for GL experiments. And that requires sending something out 500 AU out for focal length purposes. My question is somewhat theoretical so assume there are no alignment issues for the following thought. Are we not already at the "focal point/line" of some other 'entities' (sun/heavy body/galaxy/etc) gravitational lens?
Hmm... is that what this paper is talking about - the fact that the GL observation was made from Earth on some infinite focal length. Listening to other YT videos on the topic seemed to imply the resolution would be much higher. Or is the resolution location/technology related?