Levelling

1
Levelling
Summary of last weeks work
Check tripod is on stable ground or dig feet well
in.
Use pond bubble to set approximately vertical
standing axis.
Eliminate PARALLAX every time we sight the staff
2
Levelling
At every instrument set up - always start with a
BS to a point of known RL.
At every instrument set up - always finish with a
FS.
Either the instrument moves or the staff
moves NEVER BOTH
ALWAYS CLOSE levelling to a point of KNOWN RL
3
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