Pupils and Stops Flashcards
another way to say what is the field of view of the instrument?
the lateral extent of an object that can be seen while using the instrument?
the brightness of the retinal image depends only on the
pupil diameter
the field of view is directly proportional to the
diameter of the magnifying lens
of the two apertures (stops) of a system, which ones determine what?
- one determines image brightness (eye pupil)
- other determines field of view (lens diameter)
the one stop that determines field of view is also called the
field stop (FS)
the one stop that determines brightness of retinal image is also called the
aperture stop (AS)
definition of a stop
a stop is any optically clear circular aperture that is centered on the optical axis of an optical system
aperture stop (AS) of an optical system is defined as
that stop that most limits the size of a pencil of rays from a given axial object point
entrance pupil (EP) of an optical system is defined as
the image of the AS through all preceding lenses
exit pupil (XP) is an optical system is defined as
the image of the AS through all following lenses
locations of the AS, EP, and XP for an astronomical telescope design
- the objective lens (first lens) is the AS and EP
- the XP is the real image of the objective lens (first lens) through the ocular lens (second lens)
the field stop (FS) of an optical system is
that stop, other than the AS< that most limits off-axis pencils through EP, AS, and XP
the chief ray must pass through the centers of the ___ and ___
AS and XP
the chief ray is defined as the
central ray of an off-axis pencil and the most representative ray of that pencil
the entrance window (EW) is the
image of the FS through all preceding lenses
