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Tagged with: Radius of Curvature Measurement

Measurement of Radius of Curvature (ABSTRACT)

ABSTRACT: The most common use of the Point Source Microscope (PSM), or any autostigmatic microscope, is the precision measurement of the radius of curvature of spherical surfaces. This note describes the procedure for doing so and defines confocal and Cat's eye focus.

Measuring the Four Paraxial Lens Parameters using an Autostigmatic Microscope (ABSTRACT)

ABSTRACT: Describes using an autostigmatic microscope (PSM) to find the two radii, thickness and index of a singlet lens by making 4 distance measurements similar to those used to measure the radius of curvature of a concave mirror, and then using the 4 distances to iteratively calculate the 4 paraxial lens parameters using an Excel spreadsheet and its Solver application.

The Autostigmatic Microscope (ABSTRACT)

ABSTRACT: This relatively recent (1983) paper by W. H. Steel of CSIRO is the only paper found in the archival literature to describe an autostigmatic microscope (ASM) and its most common use, the measurement of radii of curvature, in this case, the radii of contact lenses. The Point Source Microscope (PSM) is a modern version of this classical instrument.

Case Studies & Testimonials

  • How small can the PSM be used for centering on a cylindrical axis?

    The PSM is an ideal tool for finding the center of curvature of a ball or the axis of a cylinder. The question is for how small a ball or cylinder can the PSM do this?

    The smallest article that was readily available was a piece of monofilament 8 pound test fishing line that was 290 μm in diameter. There was no problem finding the axis of the fishline, and separating the Cat’s eye reflection from the surface from the confocal reflection of the axis. The experiment was done with a 5x objective, and the result would have been even more definitive using a 10x objective.

  • Why is proper alignment so important?

    Here is a case of a very happy customer due to better optics.

    A few days ago an astronomer friend of mine commented that he had gotten the optics of his telescope improved and the improvement reduced the time it took to get data by a factor of 3. For an astronomer this is a dramatic improvement since observing time on large telescopes can cost thousands of dollars an hour.

    My friend did not say how the optics had been improved, but the important point is that better optics, whether due to figure errors, mounting or alignment mean more productive optics. I generally think of better optics as a better product leaving the manufacturing facility without thinking about how much the better optics mean to the productivity of the customer.