[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
Re: [ATM] TDE on a 6f6 mirror
Hi Dale,
Here are two pictures with the lights turned on. CAUTION, these are
1.2M files each.
Zoomed in:
http://www.atmlist.net/contrib/anthony-dot-anconetani-dot-atm-at-gmail-dot-com/vin.JPG
Zoomed out:
http://www.atmlist.net/contrib/anthony-dot-anconetani-dot-atm-at-gmail-dot-com/vin_zoom_out.JPG
I guess it looks like the knife edge is vignetting the right side of
the mirror. Is that correct?
It's pretty difficult to get my little Olympus to capture the whole
mirror. Even when I get the lens within a 1/8 inch of the knife I
often end up with the knife encroaching on the right or a discrete
clip on the left side.
I tried to get my camera adjusted into a sweet spot. Here is a picture
with the lights on.
http://www.atmlist.net/contrib/anthony-dot-anconetani-dot-atm-at-gmail-dot-com/vin_better.JPG
And here is a picture with the lights (mostly) off.
http://www.atmlist.net/contrib/anthony-dot-anconetani-dot-atm-at-gmail-dot-com/vin_better_dark_crop.JPG
I can at least see a little bit of diffraction on the right side now.
Does this look like a better setup to you Dale?
Thanks for looking at this stuff.
-Anthony
On Nov 20, 2007 12:30 AM, Dale Eason <atmpob@yahoo.com> wrote:
> It looks like camera lens vignetting to me. You did
> not get the full disk. When the knife is completly
> pulled out you should see both edges of the mirror.
> We don't see that. Next try turning on the room
> lights and turning off the LED. So that we see the
> mirror in normal light. Next turn on the LED. Keep
> the zoom at the same settings for both.
>
> I think you will see that only part of the mirror is
> illuminated. In reality you are only seeing part of
> the returning light cone.
>
> Your eye actually has a wider lens opening at this
> point or perhaps you have faster feedback and can
> adjust yourself so that your eye is not vignetted.
> Small digital and most video camera lens have a very
> small opening inside of the zoom lens.
>
> You seem also to have a lot of air currents that make
> it look bumpy. These bumps look different than the
> last set so I think that is air currents.
>
> I think Mike was refering to the classic sign of astig
> when the shadows are not the same on the top and
> bottom. I think that is probably air currents and not
> on the glass.
>
> Dale Eason
>
> --- Anthony Anconetani
> <anthony.anconetani.atm@gmail.com> wrote:
>
>
> > Good evening guys,
> >
> > Vladimir, thank you for looking at the pictures.
> > Yes, a bunch of
> > things changed between picture 1 and 2. I wasn't so
> > much interested in
> > explaining the difference between the two pictures.
> > Rather, I was
> > guessing that the bright left side could be a
> > reflection from the
> > inside side of the mirror. But the more I think
> > about it, the more I
> > suspect the edge is just turned down.
> >
> > Dale and Mike,
> >
> > Well, I took two more pictures at about zone 2. Here
> > is the first with
> > the knife edge backed out.
> >
> >
> http://www.atmlist.net/contrib/anthony-dot-anconetani-dot-atm-at-gmail-dot-com/zone2_no_knife_crop.JPG
> >
> > It doesn't look to me like the the camera is
> > vignetting the light
> > cone. I think that dark edge on the right is rolling
> > down. Is that
> > what you think Dale?
> >
> > Here is the second picture with knife brought in:
> >
> >
> http://www.atmlist.net/contrib/anthony-dot-anconetani-dot-atm-at-gmail-dot-com/zone2_crop.JPG
> >
> > This picture still bugs me. Without the camera, the
> > rolled edge/TDE
> > doesn't look as bad and I can see a faint
> > diffraction on the right.
> > Are digital cameras a little more pesimistic (or
> > maybe unbiased 8-)
> > then eyes?
> >
> > Mike,
> >
> > You mentioned astigmatism. Looking at the picture
> > zone2_crop.JPG is
> > lumpyness causing the astigmatism? Or do you see a
> > bigger problem?
> >
> > What's the difference between a "rolled edge" and a
> > "turn down edge"?
> >
> > Lastly, yeah blue LEDs... Too Cool... I got that
> > idea from some guy
> > up in Illinois. 8-) Actually, I saw them in DigiKey
> > and couldn't
> > resist.
> >
> > -Anthony, Round Rock TX
> >
> > On Nov 19, 2007 4:02 PM, Mike Lockwood
> > <melockwo@uiuc.edu> wrote:
> > > Hi,
> > >
> > > Dale Eason wrote:
> > > > There is the possibility that the camea lens is
> > > > vignetting the right side of returning light
> > cone.
> > > > That happens a lot with small cameras with zoom
> > > > lenses. It can also happen if the camera lens is
> > not
> > > > close enough to the knife.
> > >
> > > Good point.
> > >
> > > > To know for sure back the knife out of the image
> > and
> > > > then take a picture. If the mirror is not fully
> > > > illuminated then that is indeed the case. If
> > the
> > > > mirror is completly lit then then edge is
> > turned.
> > >
> > > Let me add to that - IF the mirror is completely
> > lit then you have a
> > > rolled outer ZONE, as well as TDE. You also have
> > some astigmatism
> > > because the shadows are not symmetric, and/or
> > possibly roughness or
> > > turbulent air in the testing room.
> > >
> > > Let's hope that the mirror was not fully lit and
> > the next set of
> > > photos is better.
> > >
> > > I like the blue color. :)
> > >
> > > Mike Lockwood
> > >
> > >
> > > _______________________________________________
> > > ATM mailing list http://www.atmlist.net/
> > >
> > _______________________________________________
> > ATM mailing list http://www.atmlist.net/
> >
>
>
>
> ____________________________________________________________________________________
> Never miss a thing. Make Yahoo your home page.
>
> http://www.yahoo.com/r/hs
>
_______________________________________________
ATM mailing list http://www.atmlist.net/