Earlier quoted context omitted.
On a serious note, how heavy does an object have to be for gravitational lensing or bending to be noticeable with a naked eye? s/visible/noticeable s/noticeable/noticeable with a naked eye s/lensing/gravitational lensing
Depends on how you define "noticeable". If you can measure a small enough distance, you can see the lensing effect of any object.
Now, figuring out this limit is left as an exercise for the reader as it's way beyond my abilities.