Author Topic: Duplicated and Distorted Fiducials  (Read 7515 times)

Offline Combat Wombat

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Duplicated and Distorted Fiducials
« on: October 20, 2022, 04:19:09 PM »
In the Apollo photographic record there are dozens of duplicated and distorted fiducials. They mostly occur on color images and when the camera is pointed directly at the sun or the sun is just out of the frame but it's flare is still visible on the image and often you'll have a beautifully framed and composed image sans duplicated fiducials followed by a mess of an image then a return to normality! I'll post 3 snips as examples.

First up we have AS14-67-9387, the center fiducial is duplicated, one is partially superimposed over the lens flare the other is partially obscured by it There are 2 duplicated fiducials flanking it, they are slightly askew. The next is a snip from AS14-66-9306, there are 4 duplicated fiducials surrounding the flare, 3 are extremely distorted, one much less so. Finally we have AS17-147-22579 with 6 fiducials duplicated, including one over the LM.

I could post many examples as I've found them in missions 12, 14, 15, 16 and 17 so far. What's causing this anomaly?

Thanks, CW

Offline Allan F

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Re: Duplicated and Distorted Fiducials
« Reply #1 on: October 20, 2022, 04:24:01 PM »
Internal reflections between the front and back pane of the reseau plate.

EDIT: No, reflections between the reseau plate and the back end of the lens part nearest it. The shape of the "extra" fiducials corresponds to the shape of the rear lens element.
« Last Edit: October 20, 2022, 04:25:52 PM by Allan F »
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Offline onebigmonkey

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Re: Duplicated and Distorted Fiducials
« Reply #2 on: October 21, 2022, 02:11:39 AM »
If you draw a line through the centre of each duplicated cross, they will merge at the light source :)

Offline Obviousman

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Re: Duplicated and Distorted Fiducials
« Reply #3 on: October 21, 2022, 04:28:28 PM »
Internal reflections between the front and back pane of the reseau plate.

EDIT: No, reflections between the reseau plate and the back end of the lens part nearest it. The shape of the "extra" fiducials corresponds to the shape of the rear lens element.

Correct. I contacted Hasselblad about this very issue, and they kindly explained what was causing it. I still have the email.... somewhere.....

Offline BertieSlack

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Re: Duplicated and Distorted Fiducials
« Reply #4 on: October 28, 2022, 05:26:18 AM »
......reflections between the reseau plate and the back end of the lens part nearest it.

GoneToPlaid made a video about this (now sadly unavailable since he closed his YT channel)

Offline BertieSlack

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Re: Duplicated and Distorted Fiducials
« Reply #5 on: October 28, 2022, 05:55:39 AM »
If you draw a line through the centre of each duplicated cross, they will merge at the light source :)

And the distortions are pretty much symmetrical around the light source too:

Offline Allan F

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Re: Duplicated and Distorted Fiducials
« Reply #6 on: October 28, 2022, 11:55:19 AM »
......reflections between the reseau plate and the back end of the lens part nearest it.

GoneToPlaid made a video about this (now sadly unavailable since he closed his YT channel)

Such a shame. Can't somebody reach out to him and host the videos on their own channel?
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline Peter B

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Re: Duplicated and Distorted Fiducials
« Reply #7 on: November 08, 2022, 04:17:57 PM »
......reflections between the reseau plate and the back end of the lens part nearest it.

GoneToPlaid made a video about this (now sadly unavailable since he closed his YT channel)

Such a shame. Can't somebody reach out to him and host the videos on their own channel?

Just a thought, but I saw some GTP videos on the Apollo Lunar Surface Journal website. Maybe it's available somewhere there?
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