The actual time in the air would be 5.9 hours (probably longer, since spec sheet range numbers usually are at economy settings, but speed is quoted at 75%). Two fuel stops, however, are going to add 1.5 hours (45 minutes per stop, which is conservative) for a total of 7.3 hours.
A normal lens or normal prime is a lens with a focal length about equal to the diagonal size of the film or sensor format, or that reproduces perspective that generally looks natural to a human observer under normal viewing conditions.
Image erecting optical system for astronomical telescopes (Erecting eyepiece). In optics, a relay lens is a lens or lens group that inverts an image and extends the optical tube. Relay lenses are found in endoscopes and periscopes for the purpose of extending the system, and before eyepieces for the purpose of inverting an image.