Rainbow rings (the secret revealed)

rjlittlefield · Post by **rjlittlefield** » Sat Apr 26, 2014 6:23 pm

It's been a while since we had a puzzle piece, and I'm thinking these images that I shot last night just might fill that bill.

With no information about how they were shot, can somebody guess what they are?

(Spoiler alert: the answer can now be found on page 3 of the thread, HERE.)

--Rik

Edit: to adjust title

canonian · Post by **canonian** » Sun Apr 27, 2014 6:22 am

My shot in the dark at this? (no pun):
They look like pinhole shots, as if you put black cardboards with different diameter holes in front of a lensless camera, directly to the sensor.

I could easily be completely and utterly wrong about this.

You did shoot this at night so are they stars I'm looking at?
Probably pointed your camera at the moon or a star?

Stevie · Post by **Stevie** » Sun Apr 27, 2014 7:51 am

To me it looks like a artificial star .

soldevilla · Post by **soldevilla** » Sun Apr 27, 2014 8:27 am

If it is a star, is the best collimated telescope I know!

DQE · Post by **DQE** » Sun Apr 27, 2014 6:15 pm

I can't offer a realistic identification of these interesting patterns, but here's a highly unlikely explanation:

I suggest that these are images of inertial confinement fusion targets, where one focuses multiple extremely high-energy laser beams on a tiny pellet of heavy isotopes of hydrogen. If you have enough energy and are VERY accurate in focusing the beams, you will compress the hydrogen and cause fusion of the atoms to occur along with a release of energy.

Here's a link to an explanation of this subject, and to some images that sort of look like Rik's images:

http://en.wikipedia.org/wiki/Laser_fusion

http://en.wikipedia.org/wiki/File:1995_ ... target.jpg

http://en.wikipedia.org/wiki/File:Inert ... fusion.svg

rjlittlefield · Post by **rjlittlefield** » Sun Apr 27, 2014 9:45 pm

I always like posting puzzle pieces because the suggestions give me more ideas that I never would have gotten by myself.

Fred, these were definitely shot with a lens, aperture diameter 2.5 mm. I've never played much with pinhole cameras, but I am under the impression that they would never produce star images with dark centers like some of what we see here. Is that not correct?

Stevie, I'll go along with "artificial star".

But then we're faced with Soldevilla's point about collimation. That one is particularly troublesome in light of the following images. One of these was shot with optics that are priced at only $70 new, with free shipping. By the way, there are three different sets of optics used here (four, counting the first posting). Collimation adjustments are impossible in every case.

Phil, I have to admit that your inertial confinement fusion targets do look remarkably like my images.

However in my case the images were formed by focusing a continuum of very low-energy light waves onto a small bit of silicon, mostly resulting in a sudden release of air sounding roughly like "Aha!"

Any more ideas? Exactly what are these, and why might I have been excited to see them?

---Rik

Stevie · Post by **Stevie** » Wed Apr 30, 2014 1:02 am

but I am under the impression that they would never produce star images with dark centers like some of what we see here. Is that not correct?

If these were done with a pinhole , there wouldn't be any chromatic aberration .
Also these seem to be out of focus .

Pau · Post by **Pau** » Wed Apr 30, 2014 9:20 am

The diffraction pattern around a pinhole or other minute point of light?.
I've seen something similar but I can't remember where.

johan · Post by **johan** » Wed Apr 30, 2014 9:31 am

Diffraction from silicon wafers hit with synchrotron radiation?

canonian · Post by **canonian** » Wed Apr 30, 2014 2:05 pm

rjlittlefield wrote:... I am under the impression that they would never produce star images with dark centers like some of what we see here. Is that not correct?

You're right, Rik, 't was a mere first try.

I give up...Did you manage to shoot the Higgs boson particle? Did you buy the DIY CERN home kit and dug out a huge circle in your garden?

I'm now beginning to see approx. 15 circular lights, but still can't bake any cake from it.

A small clue could help us further.

rjlittlefield · Post by **rjlittlefield** » Wed Apr 30, 2014 5:23 pm

canonian wrote:A small clue could help us further.

Hhmm, what to offer, what to offer? Perhaps some motivation...

rjlittlefield wrote:Exactly what are these, and why might I have been excited to see them?

The answer to the second part is perhaps the most important.

While investigating an optics problem of practical interest to myself and others, I got some theoretical results that predicted if I looked a certain way I should see some interesting patterns. So I looked that way, and saw these:

Predicted

Observed

That's why I got excited: experimental confirmation of an odd-looking theoretical result.

Stevie wrote:If these were done with a pinhole , there wouldn't be any chromatic aberration

Well, even pinholes can make colored rings. And I guarantee there is no chromatic aberration in the lens model that made the prediction.

The subject, as guessed earlier, is an artificial star, a pinhole, a minute point of light. And indeed, these are diffraction patterns.

The optics setups for these shots are actually the rear ends of classic setups involving Mitutoyo objectives, with two unusual adjustments.

So now: what is the setup, what are the two unusual adjustments, and what makes the rings colored?

--Rik

Edit: to change the folder location of one image.

Stevie · Post by **Stevie** » Thu May 01, 2014 3:53 am

Well, even pinholes can make colored rings.

Caused by diffraction perhaps ?
In any case i wanted to see that for myself and turn my 40D in a pinhole camera and used a flashlight with pinhole .
I'll post the result here if intrested , not to hijack this thread though .

rjlittlefield · Post by **rjlittlefield** » Thu May 01, 2014 8:53 am

Stevie wrote:
Well, even pinholes can make colored rings.
Caused by diffraction perhaps ?

Yes, as shown at http://www.photomacrography.net/forum/v ... 598#123598 . The reason is simple enough in retrospect. The width of the Airy disk depends on wavelength, so the outer ripples appear in different places for different colors. If you expose enough to see the outer ripples, the colors are immediately evident.

In any case i wanted to see that for myself and turn my 40D in a pinhole camera and used a flashlight with pinhole .
I'll post the result here if intrested , not to hijack this thread though .

If your pinhole results are different from mine, I would be interested to see them, but in a different thread.

Thank you for keeping this one focused on these odd-looking rings that are clearly not Airy disks.

--Rik

Planapo · Post by **Planapo** » Thu May 01, 2014 9:40 am

Rik,

Did you use your infinity Mitutoyo (which is in itself corrected) on a finite microscope with corrective projective or eyepiece and thus we see a correction of chromatic aberration where there was none, hence the red light on or towards the axis and the blue light away from the axis, a sort of inversed chromatic aberration?
And your variants are the result of changes in focus, i. e. focussing and defocussing ?

--Betty

edit: I meant chromatic aberration, of course.

rjlittlefield · Post by **rjlittlefield** » Thu May 01, 2014 10:07 am

Planapo wrote:Did you use your infinity Mitutoyo (which is in itself corrected) on a finite microscope with corrective projective or eyepiece and thus we see a correction of spherical aberration where there was none, hence the red light on or towards the axis and the blue light away from the axis, a sort of inversed spherical aberration?
And your variants are the result of changes in focus, i. e. focussing and defocussing ?

One small but important part of this suggestion is exactly correct. The rest is completely not.

--Rik