5: Parabolizing page - Cyrille-de-Brebisson/CBScope GitHub Wiki

This page is there for you to follow on your progresses while parabolizing a mirror.

At the top you can select the number of zones (with the suggested number of zone displayed there) as well as the zones start and stop as a distance from the mirror center. If you have a “normal” mirror, the first number there will be 0 and the last on the mirror radius. If you have a hole in the mirror, the first number will be the radius of the hole. The “auto calc zones” button will use whatever you have placed as first and last numbers and calculate equi-sized zones for your mirror.

This is also where you specify if your light source is fixed or moving (slit is moving).

Press on the “add measure” button to create a new Foucault measure. You can then enter the measured values (in mm) in the appropriate boxes (as well as comments and the time that you spent doing the work). If you are taking multiple measures, you can enter the various measures for the same zone as a space separated string and the system will take the average. “1 2” for example will be averaged into a reading of 1.5.

The display will provide you with the curve that your mirror makes above the sphere. Color codding of the vertical axis (which is labelled in nano-meter) tells you how close you are to the ¼ wave target. The display will indicate the lambda value (you are looking for 4 or more), as well as the other classic measurements (and I have honestly no idea what they really mean!). Of interest if the volume of glass that still needs to be removed to finish the work. The curve has the optical axis on the left and the edge of the mirror on the right.

As always, press on Delete to delete an item from the list.

Note that the zones configuration are copied for each new measurement. This means that if you change the zones that you want to work with (you start parabolizing with 4 zones and then move to 6), it should still work ok. The zones associated with each measure are written at the bottom of the display. Click on “Large view” to enlarge the display. The screen shot bellow is NOT up to date. In the latest version, the zones will be indicated with, in parenthesis between the zones the ideal reading for said zone.

The code that does the calculations has been “lifted” from Etienne de Foras “Foucault” program.