The Dual speed focuser is focusing mechanism in precision optics such as advanced amateur astronomical telescopes or laboratory microscopes.
Dual speed focuser can provide two focusing speed on a set of co-axial knobs.One for fast focusing and another for fine focusing when the film or CCD is near the perfect focus plane. This is different from two separate focusing knobs seen on low level microscopes. Another common reason to employ dual-speed focuser is the use of low focal length eyepieces, where the focus depth is short, requiring accurate focusing.
Dual speed focusing mechanism is often conbimed with Crayford focuser forming a Dual speed Crayford focuser in order to eliminate backlash effect during fine focusing.
Read more about Dual Speed Focuser: The Concept, Calculation
Famous quotes containing the words dual and/or speed:
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declining,
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convulsive,
Thy black cylindric body, golden brass and silvery steel,”
—Walt Whitman (1819–1892)
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—Albert Camus (1913–1960)