(1) Read the value of the graduation where the zero point on the vernier scale indicates.
(2) Read the value of the graduation where the two lines are aligned straight on both the graduation on the focus ring
and the vernier scale.
(3) Put the above two values together to get a total.
(1) The line of zero point on the vernier
scale is aligned straight to the line of
24 on the graduations of the focus ring.
(2) The line of 0.2 on the vernier scale is
aligned straight to a line on the
graduation of the focus ring. The value
can be read as 0.00.
(3) The total value is 24 + 0.00 = 24.00
(1) The line of zero point on the vernier scale
indicates a middle place between the
lines 24 and 24.2 on the graduations of
the focus ring.
(2)The line of 0.1 on the vernier scale is
aligned straight to a line on the
graduation of the focus ring. The value
can be read as 0.10.
(3)The total value is 24 + 0.10 = 24.10
(1) The line of zero point on the vernier scale
indicates a place between the lines 24
and 24.2 on the graduations of the focus
ring.
(2)The line of 0.14 on the vernier scale is
aligned straight to a line on the
graduation of the focus ring. The value
can be read as 0.14.
(3)The total value is 24 + 0.14 = 24.14
The vernier scale does not correspond with the zero point on the focuser drawtube.
The vernier scale can read the amount of drawing the tube in/out up to 0.02mm but the position of focus shifts
according to environmental temperature where the VSD100F3.8 is used. When the drawtube is drawn in to the end,
the vernier scale may not come to an end at zero point because of this effect. Therefore, the vernier scale on the
VSD100F3.8 is designed to go across the zero point.
4. Reading the Graduations on the Focus Ring
About the Vernier Scale
The travel of the focuser drawtube to a focal point varies with environmental temperature. Recording the readout of
the vernier scale and the corresponding temperature will be helpful in setting the focus next time. It is recommended
that you turn the focus ring in the same direction when you reproduce the focal point with the vernier scale.
Reproduction of a Point in Focus
Example 1: A total value is 24mm
Example 2: A total value is 24.10mm
Example 3: A total value is 24.14mm
Drawtube 0.02mm Increments
Vernier 0.02mm Increments
Example 1
Example 2
Example 3
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