DIYbanter - View Single Post - compressed-air drills

Doug Miller

In article , "Josepi" X-Complaints-to:
. wrote:

The three I own shoot nails farther than the eye can see in the sky.

That statement is plausible; your guesstimate of the distance at which you can
see them, however, is certainly not.

One can
only track them, depending on the sky and background, about three to four
farmers fields and then they disappear, being too small for the human eye at
about 500 metres. Yes, that is over 1/4 mile.

If you think that you can see an object 3mm x 10cm at a range of 500 meters,
then you're full of ... well, you're deceiving yourself. How do you measure
the distance, anyway?

The theoretical limit of human visual acuity is 0.4 minutes of angle. It's
completely impossible that you can see something only 3mm thick at *one*
hundred meters (0.1 minutes), let alone *five* hundred (0.02 minutes).