Groups and clusters of galaxies can be effectively found using their extended x-ray emission on sub-arcminute scales.    From Wordnik.com.  [Dark Matter in Distant Galaxy Groups Mapped for the First Time | Universe Today] Reference

The scale of the Hubble/VLA/Chandra image is probably on the scale of arcminutes (1 arcminute = 60,000 milliarcseconds).    From Wordnik.com.  [Archive 2008-08-22] Reference

So, if a normal human eye can discriminate two points separated by 1 arcminute/cycle at a distance of a foot, we should be able to discriminate two points 89 micrometers apart which would work out to about 287 pixels per inch.    From Wordnik.com.  [The Register] Reference

20deg) that last for 4 orbits and longer, resulting a total survey area of about 140~230 square arcminute.    From Wordnik.com.  [SpaceRef Top Stories] Reference