To see the supermassive black hole, the team of scientists used new red-sensitive charge-coupled devices (CCDs) installed in the Suprime-Cam camera on the Subaru telescope on Mauna Kea.
CCDs are used in many light detecting gadgets from photocopiers to bar-code readers. In astronomy they are used to collect analogue information (such as light or an electrical charge from a distant object) and convert it into digital information that can be analyzed by computer software.
(image credit: University of Hawaii)
This information is, in fact, neat. Does this explain why there are glaciers melting in the dead of night?
It's not a big deal, but the fact that light from that location has "traveled so long" to reach Earth isn't the cause of the redshift. The same effect would have happened if the object was comparatively local to us (but still traveling in the same direction relative to us). The big difference would be the magnitude and perhaps detectability of the shift.