Testing results for the optic labeled “A”

Hello again,

 

I’m going to break this page into several sections as follows:

 

  1. General Synopsis of the test results
  2. Impression of the optical surface and performance predictions
  3. Detailed Robo Foucault results and images
  4. Detailed Interferometry results and images

 

Section #1     Synopsis

 

  1. Optical Diameter = 202mm (7.9”)
  2. Radius Of Curvature = 2161mm (85”)
  3. F-Ratio = F/5.35
  4. 15 zone Robo Foucault Knife edge results: (@550nm)
    1. Axis 1 Horizontal

                                                              i.      P-V Wave Front Error = 1/2.97

                                                            ii.      Surface RMS Error = 23.3nm

                                                          iii.      Strehl Ratio = 0.755

                                                           iv.      Under corrected, best fit conic constant = -0.804

    1. Axis 2 Horizontal

                                                              i.      P-V Wave Front Error = 1/2.99

                                                            ii.      Surface RMS Error = 20.3nm

                                                          iii.      Strehl Ratio = 0.805

                                                           iv.      Under corrected, best fit conic constant = -0.892

  1. Reduction of 16 fringe image interferometric data (@550nm)
    1. P-V Wave Front Error = 1/2.18
    2. Surface RMS Error = 23.7nm
    3. Strehl Ratio = 0.747
    4. Under Corrected, best fit conic constant = -0.818

 

Section #2 Impression of the optical surface

 

  1. Sample Images:
  2. As seen in the two sample images, the optic suffers from two difficult to quantify defects
    1. Rough surface, which will degrade contrast
    2. Turned down outer zone and slight turned down edge, both of which will reduce resolution
  3. Overall I expect this optic to perform rather well, perhaps in the 30-40 power per inch range.  I would not call this a diffraction limited optic, as it’s strehl ratio of 0.75 is less than 0.8 criteria.  However it is close, has very minor amounts of primary astigmatism (1/34 p-v wave front @ 550nm), and the strehl ration is based on the entire surface of the optic.  Since the secondary mirror will mask some of the optics high center, and if the outer 4-5mm of the edge were also masked off, this will most likely push the strehl ratio high enough that the optics only limiting feature will be its rough surface.

 

 

Section #3 Detailed Robo Foucault results and images:

 

  1. First, here’s is a screen capture of the Robo Foucault results as reduced by FigureXP for each axis:
    1. Axis 1 Horizontal
    3. Axis 2 Horizontal
  2. The results can also be downloaded as one of three file types:
    1. A Figure file for use in Figure45 or FigureXP

                                                              i.      Axis 1 Horizontal

                                                            ii.      Axis 2 Horizontal

    1. A Sixtest file for use in Jim Burrows’ Sixtest reduction program

                                                              i.      Axis 1 Horizontal

                                                            ii.      Axis 2 Horizontal

    1. A plain text file for entry into any Foucault data reduction program

                                                              i.      Axis 1 Horizontal

                                                            ii.      Axis 2 Horizontal

  1. In addition to the numerical results you can also browse or download the generated knife edge images obtained during each test
    1. Axis 1 horizontal

                                                              i.      Browse images

                                                            ii.      Download Images (15Meg Zip File)

    1. Axis 2 horizontal

                                                              i.      Browse Images

                                                            ii.      Download Images (15Meg Zip File)

 

 

Section #4 Detailed Interferometry reports and Images

  1. Here is the full interferometric test report as reduced by FringeXP:
  3. This report is the aggregate result of all 16 interferograms
  4. The surface error cross section corresponds to axis 1 being horizontal, and resembles the Robotic Foucault test across axis 1.
  5. There are thee sets of interferograms that can be either browsed or downloaded
    1. Axis 1 Horizontal Interferograms

                                                              i.      Browse Axis 1 Horizontal Images

                                                            ii.      Download Axis 1 Horizontal Images (5.5Meg Zip File)

    1. Axis 2 Horizontal Interferograms

                                                              i.      Browse Axis 2 Horizontal images

                                                            ii.      Download Axis 2 Horizontal Images (3.6Meg Zip File)

    1. Axis 2 Horizontal and ROTATED to match axis 1’s orientation!

                                                              i.      Browse Axis 2 Rotated Images

                                                            ii.      Download Axis 2 Rotated Images

 

 

This completes my analysis of Mirror A.  Any questions or comments are welcomed!

 

James Lerch

jlerch@tampabay.rr.com

http://lerch.no-ip.com/atm