Bruce what you may be describing is something that happens if you try to install software but it's currently running (or an older version is running). Make sure all copies of DFTFringe are stopped (no

This is great. Several shiny new features and fixes. Nice video.

It's #1. You can multiply the epsilon portion last. Well if my steps 1-4 didn't work then I think you are probably calculating the annular null wrong. - George

1) Create a simulated igram for a full disk mirror of a given diameter and F/#. In other words perhaps set diameter to 10 inches and F/# to 5. now simulate the mirror (absolutely no need not to sue 10

Which is why I also vaguely mentioned a checkbox - somewhere in the settings - that when checked it changes the RMS column to ptv.

Enough said. Yes. That is critical. Okay, I'm sold. Yuk. Okay. That's a recurring theme with these annular Zernikes. Everything has this added dependence on the size of the obscuration. Another reason

Oh and that leads us to peak-to-peak error. It's also quite easy to convert a given Zernike term in DFTF to "peak to peak" error. I think you multiple by 2 for some of them and 1.5 for others. I knew

Oh and another issue: RMS error. You have a simple trick in DFTFringe to convert each zernike wyant value into an RMS error. Which gives you a quick idea of which Zernike terms are contributing most o

Dale - I was wondering the exact same thing back in April. I even got into a private bit of a back and forth with Michael Peck. He wasn't quite able to understand my point. It turns out the Zernike va

I don't understand the black box but here is how DFTFringe thinks of it. If fringe spacing is 1 (one). Then each fringe step (from one fringe to the next) means one of those fringes is one wavelength

The "tilt" was an example. You could also easily do defocus with a spherical mirror or say an 8 inch F/6 mirror (pretty arbitrarily chosen - the point is the NULL value in DFTF is small compared to a

Indeed. I plan to email the person making this 42 inch and discuss lens calibration or at least characterization. For example one can use a more ordinary mirror and measure it with the Bath with 50 fr

I think those "petals" were added on purpose to make sure DFTFringe could see them. I eagerly await Dale's answer. And this particular mirror (42 inch F/2.6-2.8) is not just randomly chosen but is an

1. David Rowe, 3 mirrors, 2 test plates, 2 Schmidt correctors 2. Dale Eason, 1 mirror 3. Berthold Hamburger, 4 mirrors 4. Sorin Sfartz, 1 mirror 5. Diego Dabrio-Polo, 1 mirror 6. Jan van Gastel ~30 mi

Don't mount the diverging lens to the splitter. If it's plano convex then you'll want to be able to flip it anyway as planoconvex diverging lenses will add some (usually small) spherical aberration (I

So I have this equation. But it could be wrong. C15=D/λ/(5*2^22(R/D)^7) Don't know where the -r^8 came from but I suspect the ^8 portion is wrong. My understanding is that D is indeed diameter but R i

Regarding annular zernike's. If the hole isn't perfectly centered or the hole isn't perfectly circular you might not notice problems near the edge of the hole (as they would be masked out). It seems t

Why is it different just because it's an annular? Shouldn't it be parabolic (S.A. shape) either way? Does that mean DFTF has the wrong null for annular mirrors? Or is it because you have a completely

How about instead just write out what you did - what you typed to get some results. Is there a manual? A manual combined with the exact example of what you did might be all he needs. Or even just a br

Thanks. I saved them where I can find them when I need them. Dale is definitely still working on DFTFringe. But probably not that specific algorithm. It's open source so anyone can contribute. If they