Click here to make tpub.com your Home Page

Page Title: Figure B-14. Eyelens and fields lens of eyepiece.
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home


   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 

TM 9-258
Figure B-14. Eyelens and fields lens of eyepiece.
Eyepiece - An optical system used to form a virtual,
is the maximum angle of view that can be seen at one
time. In an instrument, the true field of view is the actual
erect, enlarged image of the real image formed by the
angle of view of the instrument, the maximum angle
objective (fig B-14). The optical system of the eyepiece
subtended at the objective by any objects which can be
usually consists of two lenses, an eyelens and a field
viewed simultaneously. The apparent field of view is the
lens, but the eyepiece may contain another lens (figs 4-5,
4-6 and 4-7).
size of the field of view angle as it appears to the eye; it
Eye relief - See eye distance.
is approximately equal to the magnifying power of the
Eyeshield or eyeguard - A shield of rubber plastic,
instrument times the angle of the true field of view
or metal to protect the eyes of the observer from stray
Field stop - See diaphragm.
light and wind and to maintain proper eye distance.
Far point - The farthest point of clear vision of the
Filters or ray filters - Colored glass disks with plane,
unaccommodated eye. For the normal eye, the far point
parallel surfaces placed in the path of light through the
is infinity. See infinity.
optical system of an instrument to reduce glare and light
Farsightedness - See hypermetropia.
intensity and likewise in observing tracer fire and
Field glass - A type of compact binocular.
detecting outlines of camouflaged objects.  They are
provided as separate elements or as integral devices
Field lens - One of the leneses of an eyepiece. It is
mounted so they may be placed in or out of position as
the lens which is nearest the image upon which the
desired (fig 4-27).
eyepiece is focused. It serves to shorten the eye relief
Finite - Having limits, as opposed to infinite, or
and adds to brightness of the edge of the field (fig B-14).
without limits.
Field of view - The open or visible space or angle
Fire control - The determination and regulation of
commanded by the eye. It
the direction of gunfire.  More specifically, it refers
B-14

Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business