fiducials on the LM hasselbad?

[Lunchpacked]

Through my subscriptions I found a new "question NASA" awe130archives video

Description:

All crosshairs are missing in the Apollo 11 Magazine 37R Frames 5433-5555? According NASA the photos come from the raw scans of this magazine? What happened to the crosshairs NASA?

i explained: (blatantly copied from the comments at time of posting)

because they used different cameras inside the CM/LM than on the surface of the moon.. the ones in the CM/LM were regular cameras and had no resau plate, but the ones used on the EVA (the ones mounted to their chests) did have the plates.
you will not find any "outside" pictures taken without the crosshairs, all the photos shown here from the surface are clearly taken inside the LM (notice the height)

Lunchpacked180 1 hour ago


on Apollo 11 they brought 3 still cameras, 2 normal hasselblad 500el cameras (with viewfinders etc) used exclusively inside the spacecrafts (no modification was necessary for it to work there), and 1 modified hasselblad 500cl (with the resau plate and other mods, no viewfinder etc.) used exclusively on the EVA's. so that should explain the missing crosshairs from some magazines, they were taken with a regular camera.
you can see that crosshairs are consistent with magazines..

Lunchpacked180 in reply to Lunchpacked180 1 hour ago


If that is the case you solved our question.
Peace to you

AwE130Archives in reply to Lunchpacked180 1 hour ago


happy to be of assistance 

Lunchpacked180 in reply to AwE130Archives 59 minutes ago


Do you know why the "Calibration Chart (OF300) ( 81k )" does show crosshairs?
We will send you a pm with the link!
Peace to you

AwE130Archives in reply to Lunchpacked180 46 minutes ago


yes i noticed that.. however it does not have a catalogue name, only as11-37-chart... it intrigues me as well... let me look into it.. you are welcome to join me in the research
Lunchpacked180 in reply to AwE130Archives 13 minutes ago

so that's why I'm writing this post.


I also found that the calibration image for magazine 39 had fiducials aswell, while the rest had not.. (and i would suspect that there are similar ones from other missions as well)

Here are the images in question (i have added the next photo from each magazine for comparison)
Magazine 37

Calibration chart


Photo 5433


Magazine 39

Calibration chart


Photo 5737



I have searched both Google and here (and the archives) and even GtP's site for anything about a calibration chart but have not found anything other than the ALSJ mention..

I noticed that all the info on the slate is the same, except the magazine info and shutter time, so my uneducated guess is that  NASA / Kodak had a reference camera they used (with a reseau plate mounted) to take a picture when they received the film / when the film was made, so they had a known factor for colours/grayscale per film..

so my question is, why do the calibration images have fiducials?

I can't find any info on it.. or perhaps I'm searching for the wrong things? or the wrong places?

anyway, I wonder if any of you could help me out?

I'm pretty curious about this myself

[JayUtah]

The calibration shots are taken in the ground lab.  Hasselblad produced quite a number of the Apollo-configured cameras, some of which were "flight" articles and others were standby, test, or engineering models.  The calibration shots were evidently taken with one of the reseau-equipped EL/500s that had been assigned to that use.  This makes all kinds of sense because the reseau plate was partially silvered and would have had a very small effect on exposure settings.  It would have been important for the calibration shots to account for that.  The eventual use of some magazines in non-reseau bodies was probably not anticipated at the time the magazines were being calibrated.

[ChrLz]

And for the sake of having all the facts on hand for casual passers-by, the film 'magazines' used on the Hasselblads (as with all medium format cameras of this type) are easily interchangeable - you simply insert a 'slide' that completely covers and protects the film, then the magazine can be unclipped, put on another camera, and the slide removed so no frames are lost and there is no indication (on film) that such a swap took place...

I don't know if they took slide/s with them - there probably wasn't much of a reason to swap magazines midway through a roll during the missions.. ?  (IIRC, the slides on the cameras I used to use were not required to remove a magazine at the end of a roll of film - but on the Hasselblads they might be, in which case obviously they would have needed to take them...)


(edited to clarify last paragraph)

[Noldi400]

If we're talking about the same thing, they did indeed take slides with them - each one with a wire 'loop' attached to make them easier to handle with suit gloves.

I mainly remember because there was TV video of someone - Jack Schmitt, I think - dropping one of the slides while trying to put it in and leaving it off rather than get regolith in the magazine. I'm pretty sure each magazine had one, probably for thermal and dust protection.

[ka9q]

They sometimes swapped partially exposed magazines between cameras, so you'll see the beginning of one magazine with reseau marks and the end without them, or vice versa. I think this happened mainly when a camera failed and they wanted to use up the rest of an unused magazine, or when they needed to switch between black-and-white and color.

The ALSJ carefully notes when this was done, and you can also tell by the light-struck frames between the shots taken by the different cameras. Apparently the dark slides weren't 100% effective in protecting the film at the back of the magazine, but the important thing was to protect the film on the spools. I don't know if the astronauts were trained to handle magazines in the shade, but that would have been a good idea. When I shot film I was always careful to avoid loading or unloading a camera in direct sunlight.

[ka9q]

The calibration shots are taken in the ground lab.  Hasselblad produced quite a number of the Apollo-configured cameras, some of which were "flight" articles and others were standby, test, or engineering models.

So...what were the alpha and epsilon figures for the silver paint used on the EDC models on the lunar surface?

A hoaxer who claims the film would have instantly frozen in the shade has gotten me curious about the actual thermal behavior of the cameras. I wrote a spreadsheet with a simplified model, but without actual figures the results don't mean much.

I did discover something interesting while playing around with different numbers: a higher emissivity is actually better than a lower one. I had assumed you'd want a low emissivity to avoid picking up heat from the lunar surface and to slow your cooling rate in the shade. But even with a low absorptivity it got very hot in the sun because it was unable to get rid of the heat it did pick up from the sun. A low absorptivity minimized incoming solar heat and a high emissivity helped it get rid of the heat it did pick up. With OSR (optical solar reflector) I got equilibrium temperatures of about +25C in the sun and 0C in the shade at a sun elevation of 30 degrees, and that wasn't bad at all. Certainly not the hundreds of degrees below zero that the hoaxers like to kick around.

You can see how much it helped that all the Apollo crews were gone by noon. If we're going to have long lunar stays in the future, I suspect the astronauts are going to have to take noontime siestas (preferably underground) to avoid the worst of the heat, at least at equatorial sites.

[JayUtah]

If we're talking about the same thing, they did indeed take slides with them - each one with a wire 'loop' attached to make them easier to handle with suit gloves.

Take care, though.  The darkslides for the Apollo longrolls (which were third-party magazines from a company in Hollywood) didn't work like the typical Hasselblad darkslide.  Normally the mechanical interface between the body and the magazine requires the darkslide to be inserted before the magazine can be detached.  But in Apollo's case this was changed.  The darkslide had to be removed before attaching the magazine to the body.  As a result, some of the frames at the beginning and ending of each roll are sunstruck.  IIRC, this was done to accommodate the thicker reseau plate.

[ka9q]

The darkslide had to be removed before attaching the magazine to the body.  As a result, some of the frames at the beginning and ending of each roll are sunstruck.  IIRC, this was done to accommodate the thicker reseau plate.

Ah, so that explains the sunstruck images. I had thought the slide simply didn't do a complete job.

So you're saying that they had to swap magazines with the darkslide removed, exposing the film? I assume they were trained to shade the magazines with their bodies when they did this.

[JayUtah]

So...what were the alpha and epsilon figures for the silver paint used on the EDC models on the lunar surface?

I've never found a reliable figure for absorptivity and emissivity.  It's not just "silver paint" as some have said; the press kits and other secondary material describe the cameras as "silver-colored," leading some to believe actual silver was used.  I'm pretty sure the active ingredient in the coating is aluminum, simply from having examined the camera in detail and knowing what aluminum looks like.  But the formulation matters in Al-based thermal coatings, because they include other ingredients to alter the overall optical profile, so you can't just look up figures for aluminum.  I need to know the exact product that was used, and I don't know that yet.

A hoaxer who claims the film would have instantly frozen in the shade...

...clearly doesn't understand the time component of heat transfer.  The film, by the way, was the then-secret Estar base.  Now it's a common stock from Kodak, but back in the 1960s it was a special polyester film base that was invented for the Corona spy satellites.  It's meant for the space environment, specifically for hardiness across temperature fluctuations.

I had assumed you'd want a low emissivity to avoid picking up heat from the lunar surface and to slow your cooling rate in the shade.

Many materials intended for thermal regulation are explicitly non-Kirchoff materials.  And you typically want an α/ε ratio of around 0.1 for passive heat rejecting in sunlight.  Bare metals have that ratio up around 2 or 3, but any ratio where epsilon does not dominate will cause you problems.

But even with a low absorptivity it got very hot in the sun because it was unable to get rid of the heat it did pick up from the sun.

Yup, sucking vastly more heat that it can blow.

Certainly not the hundreds of degrees below zero that the hoaxers like to kick around.

Well that theory doesn't even begin to describe the thermal conduction and radiation paths within the magazine.  Yes, you start with the radiative heat transfer solution of the magazine, but if what you're concerned with is the thermal condition of the film, then you've only begun your homework.

[JayUtah]

Ah, so that explains the sunstruck images. I had thought the slide simply didn't do a complete job.

So you're saying that they had to swap magazines with the darkslide removed, exposing the film?

Yes, that is correct.

I assume they were trained to shade the magazines with their bodies when they did this.

Yes.  As a test, I "sunstruck" part of the roll I shot out in the desert, although it being nighttime I had to consider only the massive studio light.  With my back to the light, I got only minimal damage to the film.

[Noldi400]

Well that theory doesn't even begin to describe the thermal conduction and radiation paths within the magazine.  Yes, you start with the radiative heat transfer solution of the magazine, but if what you're concerned with is the thermal condition of the film, then you've only begun your homework.

Just for those of us without the technical education to discuss alpha and epsilon in this context, I think the problem with the HB comments on this stem partly from them being literal-minded and trying to rely on intuition. They hear -250^o in the shadows and thing that anything not in sunlight would "feel" like the inside of a very cold freezer - which obviously is not the case in a vacuum. I'll not bore you guys further with stuff you know 'way better than I do; my point is that a lot of the HBs can't seem to get their minds around the fact that the lunar environment is drastically different from earth.

Yes.  As a test, I "sunstruck" part of the roll I shot out in the desert, although it being nighttime I had to consider only the massive studio light.  With my back to the light, I got only minimal damage to the film.

I remember seeing that show, and you know what my first thought was when the night shooting started? "Huh. Would you look at that? Not one damn star to be seen anywhere."

[ka9q]

my point is that a lot of the HBs can't seem to get their minds around the fact that the lunar environment is drastically different from earth.

Exactly right. I try hard to explain the differences in qualitative terms, such as the lack of an atmosphere that's bathing everything, evening out the temperature differences, but I seem to get nowhere.

I've even said things like "if that were true, then I could build a perpetual motion machine around it" but that doesn't work either. I doubt they even accept the laws of thermodynamics; there certainly are a lot of other crackpots who don't.

[ka9q]

But the formulation matters in Al-based thermal coatings, because they include other ingredients to alter the overall optical profile, so you can't just look up figures for aluminum.  I need to know the exact product that was used, and I don't know that yet.

That's why I asked. I checked my copy of Gilmore and saw numbers for aluminum and aluminum paint that were all over the place.

People don't understand that you only see half the story by looking at a thermal coating. All you see is how it looks in visible light. When you look at a piece of optical solar reflector, that seemingly invisible thin layer of Teflon or quartz between you and the aluminum or silver makes all the difference.

The film, by the way, was the then-secret Estar base.  Now it's a common stock from Kodak, but back in the 1960s it was a special polyester film base that was invented for the Corona spy satellites.  It's meant for the space environment, specifically for hardiness across temperature fluctuations.

Oh, that's good to know. I knew about Estar but I didn't realize it was secret at the time. I just knew it was thinner than usual so they could pack more into each magazine.

any ratio where epsilon does not dominate will cause you problems.

Yes, I see that now.

but if what you're concerned with is the thermal condition of the film, then you've only begun your homework

Sure. But if I can assume the film is completely enclosed by a solid metal box with good heat conductivity, then I can reasonably assume that the film will come to an equilibrium temperature equal to that of the box. It's not like a spacecraft where internal nodes are dissipating heat.

[JayUtah]

Just for those of us without the technical education to discuss alpha and epsilon in this context...

I apologize; ka9q and I lapsed into technical jargon.

Electromagnetic energy is either absorbed, reflected, or transmitted through a substance.  Each substance behaves differently.  But all the incident energy has to be accounted for by those phenomena, so we represent them as three coefficients (named with Greek letters) that together sum to 1.  The absorptivity (Greek alpha) of an object principally determines the heat it receives from incoming light energy.

In addition there is a property called emissivity (Greek epsilon) that determines how readily a hot object gives away heat by radiation.  The complex interplay among all those values determines the temperature of the material under various conditions.  The ratio of absorptivity to emissivity describes a relationship between how fast a material can acquire heat from light energy versus how fast it can give away heat in the form of light energy.  Think of it as how fast you can fill up a sandbox with your shovel versus how fast someone else can empty it with his; depending on how those rates vary, the sandbox will fill up either a lot or a little.

I remember seeing that show, and you know what my first thought was when the night shooting started? "Huh. Would you look at that? Not one damn star to be seen anywhere."

Yes, and we followed up on that in the photo-lab scene.  The lens was at f/5.6 and shooting at 1/60 second.  Ironically that was the night of the especially bright Mars.  I was able to photograph that with a separate camera, but only by using a long exposure.

[Noldi400]

I apologize; ka9q and I lapsed into technical jargon.

No problem. He asked a technical question, you answered in technical terms; totally appropriate. I got the gist of it.

Also, Jay, have you seen my last post about Hunchbacked over on the 'old friends' thread? He's really gone off the cliff, I think.