ATAGO NAR-2T - Page 40

39
12. Finding average dispersion value and Abbe number
Tu r n the color compensator knob
clockwise until the boundary line is
achromatized, and read the indication
of the dispersion scale at the time.
Next, turn the color compensator
knob counterclockwise until the
boundary line is achromatized, and
read the dispersion scale indication at
that time. Alternately repeat the
above-mentioned operations several
times and calculate an average value
(Z) of the several measurement
results.
With the obtained value (Z), find the
value of a on Ta ble 2 on page 41.
6. Finding value Ș more
accurately
Calculation method for reference
=0.02337+(㸫2)2710
-7
=0.02337㸫5410
-7
=0.02337㸫0.0000054
Ҹ 0.02336
=0.02786+(㸫46)2710
-7
=0.02786㸫121510
-7
=㸫0.596
=0.02798(㸫0.596)=㸫0.01653304
A+BȘ=0.02774㸫0.01653=0.00683
Ȥ=
nD㸫1
nF㸫nC
=
0.4827
0.00683
=70.7
A
B
Ș
Ҹ 0.02774
Ҹ 㸫0.01653
=0.02786㸫0.0001215
BȘ