# Tagged with: Mid-spatial Frequency Errors

## Optical Surface Specification using the Structure Function (ABSTRACT)

ABSTRACT: A tutorial on use of the structure function (SF) as a specification to limit the effects of mid-spatial frequency roughness. The paper points out that the SF units of measurement are familiar to opticians and optical engineers and that it is easy to calculate the SF without making ambiguous assumptions as opposed to the use of Power Spectral Density function (PSD).

## The Structure Function as an Optical Surface Specification (ABSTRACT)

ABSTRACT: A tutorial paper on how to use the structure function as a specification (SF) to limit the effects of mid-spatial frequency roughness. It also points out that the SF units of measurement are familiar to opticians and optical engineers and that it is easy to calculate the SF without making ambiguous assumptions as opposed to the use of Power Spectral Density (PSD).

• ### "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.

### Worldwide Representatives

OPTurn Company Ltd
R607, Yingzhi Building, 49-3 Suzhoujie Str.
Beijing, China
+86-10 62527842
This email address is being protected from spambots. You need JavaScript enabled to view it.

+81-3-5918-8501
This email address is being protected from spambots. You need JavaScript enabled to view it.

Kiyohara Optics Inc.
3-28-10 Funado Itabashi-Ku Tokyo, Japan 174-0041