Calibration Package for PSM Angular Measurement

OPG offers a PTB traceable 1” diameter window with an approximate 30 arc minute wedge measured for exact value to better than 1 arc second on a Trioptics PrismMaster and a Certificate of that measurement. The window is used to calibrate the PSM detector to change to distance, measured in μm between the reflected spots from front and rear surfaces of the uncoated window into minutes and seconds of arc.
Price / kg:

The package includes an unmounted 25.4 mm diameter by 5 mm thick N-BK7 window with an approximate wedge between the surfaces of 30 arc minutes packaged in a clean room compatible box, a Certificate with the precise measured value of the wedge angle to less than 1 second of arc and a Certificate of Conformance. The package is priced at $460 plus $40 shipping and handling.

In the early days of the PSM there was only one camera available so it was easy to have an internal calibration to change the distance measured on the video screen converted into minutes and seconds of arc. With the variety of camera format now available it is no longer possible to assure the conversion from distance to angle, particularly when some customers change cameras as the technology improves.

We now use the Certified wedge to make the conversion from the μm shown on the screen to angle by simply placing the wedge in front of the PSM with no objective so there is collimated light coming from the objective port, and recording the distance between the spots reflected from the front and rear surfaces of the wedge. The angle, α, between the 2 spots is equal to 2*β*n where β is the angle of the wedge on the Certificate and n is the index of the N-BK7 at 636 nm, the wavelength of the PSM laser diode, 1.515.

For occasional measurements of angle, it is easier just to use the ratio of μm to angle using the wedge. For extended use of the PSM for angle measurement, the Calibration Factor on the Cal Tab can be adjusted so the μm reading converts directly into seconds or minutes of arc.


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Case Studies & Testimonials

  • "As always we are very much loving the instrument, I personally love the camera upgrade from what I'm used to!"

    Weslin Pullen
    Hart Scientific Consulting International, LLC
    Tucson, Arizona


  • 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.

  • 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.

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OPTurn Company Ltd
R607, Yingzhi Building, 49-3 Suzhoujie Str.
Beijing, China
+86-10 62527842
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上原 賢司   Kenji Uehara
清原光学 営業部   Kiyohara Optics / Sales
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Kiyohara Optics Inc.
3-28-10 Funado Itabashi-Ku Tokyo, Japan 174-0041

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