Theory
Adjustment which are performed
at each set up of level trial to the actual work of taking observation called
as temporary adjustment. Ones the instrument is permenantally adjustment than
at each new position level is temporary adjustment in following operation to
set axis of rotation process is also known as setting temporary adjustment for
dumpy level are
a) Setting
up level
b) Leveling
of level
c) Focusing
and elemenation of parallar
Diagram
Procedure
Setting up level
In this operation first of all
the level was taken out from box by holding in right hand and dumpy level is
fixed at the top of tripod by turning round only the leveling head with the
left hand. Length of tripod stand where spread in such a way so that level remains
stable. Then the level screws were brought in the centre of their run and
adjustment the height of instrument by moving the length so that levelle or
level man to take reading easily.
Leveling of level
Telescope was turn so that it
should be paralled to two legs pressed into the ground by third leg the
longitudinal bubble was brought to the centre approximately and at this stage
third leg was pressed into the ground. Accurate adjustment of level was done by
moving telescope parallel to any pair of foot screw and applying the rule right
in and left out moved the foot screw inward or outward and brought the bubble
of longitudinal level in centre than telescope was moved 900 any
clockwise manner so that it was exactly over the third foot screw. Here the bubble
was placed the centre by its third foot screw by applying same rule.
Focusing and elemenation of
parallax
Apparent movement of image of
an object with respect to cross hair when image from by object glass does not
falled in plane of dyform is called as parallax. It was tested by moving the
eye up and down in case image fixed to cross-hair on movement of eye there is
no parallax on the other hand it image goes same direction as that of eye there
is parallax which is removed by focusing the eye piece of object tube a sheet
of white paper present in front of object glass and seen to eye piece and by
adjusting the eye piece in handout in its sockets. The crosshair wear made
disting and clear.
