Why are there no stars seen on the pictures of the moon?

[ka9q]

Modern computers and digital photography simply weren't available in 1969.

I understand. But the fun of these discussions is that they so often go off on interesting and insightful tangents that don't necessarily have to do with Apollo.

Image stacking is really a fancy name for what photographers call "bracketing".

It's more than that. Stacking is combining the best sections from the focus- or exposure-bracketed shots into a single, synthetic shot. In simple bracketing, you pick the best shot and throw the rest away.

<esoteric analogy>In my field of digital mobile radio communications it is standard practice, at least for the technology (CDMA) I helped develop, for base stations to combine the raw signals from several antennas before demodulation to reduce multipath fading. This is maximal ratio combining and it's something like photographic stacking. This is an enhancement of an earlier and still very common technique called voting where you pick the best signal at any moment from several independent  antenna/receiver/demodulators and ignore the others. This is like photographic bracketing. </esoteric analogy>

I should have said that it ASA wasn't a universally accepted standard until the early 1980s

Well, "ASA" does mean "American Standards Association" so that sort of goes without saying (except for the not-insignifcant number who think nothing outside America matters, but...)

According to the Wikipedia article, the separate ASA and DIN numbers were merged into "ISO ASA/DIN" in 1974.

AIUI Kodak were asked by NASA to develop special thin films emulsions for the Apollo missions

That's their ESTAR base, Kodak's trade name for polyester -- aka DuPont's Mylar. The emulsion is actually the same, but the base (which is nearly all of the film's thickness) can be much thinner because polyester is far stronger than cellulose acetate. It also has a much wider temperature range, something the Apollo deniers who think the film would have instantly frozen or melted ought to know.

Kodak points out an interesting drawback to ESTAR. It's so strong that a film jam can damage a camera or projector. Cellulose acetate breaks first. (I'm reminded of the old joke in electronics repair about the expensive transistor that blew to protect the fuse.)

Kodak had just introduced "Ektachrome" to eventually replace their existing "Kodachrome" transparency film

I think Ektachrome had been around for a while before Apollo; my dad shot a lot of slide film in the late 1950s and early 1960s and a lot of it is Ektachrome. Wikipedia says it was developed in the early 1940s.

I was somewhat surprised that NASA chose Ektachrome as it's notorious for fading, with images going red due to fading of the cyan dye. Kodachrome is much more stable precisely because the dyes are added during processing, not constructed by adding to components already in the film. But I guess this problem can be (and has been) solved with storage at low temperatures. And as you say, Ektachrome had the advantages of higher speed, wider exposure latitude and much simpler processing that's harder to screw up.

[Kiwi]

Why are there no stars seen on the pictures of the moon?

In case it hasn't been put this way, in the simplest terms, as far as films of the '60s, '70s and later were concerned:

A fully-sunlit scene is between 30,000 times and 130,000 times brighter than any reasonably-good scene showing stars.

Most standard films just cannot handle that sort of lighting ratio and nor can most standard electronic cameras. They can usually handle only a lighting ratio of about 11 f-stops or 1024:1, which is quite sufficient for most photos taken on or near Earth or its moon. We can shoot stars and we can photograph sunlit scenes, but not both at once.

With 125 ISO film, the normal full-sunlight exposure is 1/125th of a second @ f16.  It's called the Sunny 16 rule. A photo which shows bright, recognisable constellations technically requires an exposure of about ten seconds @ f2.8 with the same film, but in practice another factor called reciprocity failure crops up with long exposures, and even longer ones such as 20 or 30 seconds are sometimes required.

This old post at the CosmoQuest forum (formerly BAUT and Bad Astronomy) shows the differences between some of those exposure settings.

My maths has never been too good, but I once worked out that if you got out as far as Pluto in its average orbit around the sun, it would be too dim for you to get a sharp hand-held full-sun photo of it on standard film, but if you took a sharp and properly-exposed shot of it and included plenty of sky, you still wouldn't see most stars in the photo.

I'll leave it to the experts to prove that right or wrong.

P.S.
It has been wonderful to see more than two people talking about films and related technical matters of the Apollo era.  I don't think I've ever seen that before.

My particular technical expertise revolved around simplifying Ansel Adams and Fred Picker's experiments with the Zone System and passing on the results to anyone else who was keen to listen and to do their own simple experiments.  Due to my poor maths I made the very fortunate mistake of starting with a contrast of 11 zones, 0 to 10, which required halving the film speed and gave spectacular black-and-white prints which had an almost-3D look that few colour prints had, and made other photographers say, "Wow!  How did you do that?"

The system gave repeatable results, required only a two or three films and a few hours to perfect, and cut out the need for any fancy enlarging computer or time- and money-wasting test prints.  I used a stick with numbers on it beside the enlarger and used to think I was printing badly if it took 11 sheets of paper to get ten top-notch prints.

Even Ansel Adams, through his own experiments, later came around to my way of thinking about 11 zones. And damnit, a few months ago I found the article he wrote and put it away so carefully that I can't find it right now.

[JayUtah]

Stacking is combining the best sections from the focus- or exposure-bracketed shots into a single, synthetic shot. In simple bracketing, you pick the best shot and throw the rest away.

Right.  In film photography, especially with finicky emulsions like Ektachrome, your metered exposure may not be the best exposure.  Hence you trust your meter to get you into the ballpark, then bracket to see where the nuance falls.  And it's a full-frame proposition.  If you wanted selective exposure control you had to dodge and burn during printing, which is obviated in Ektachrome.  In the late 1980s I shot quite a bit on Agfa and Fuji reversal films and got pretty good at not having to bracket in order to get good dynamic range.

This is maximal ratio combining and it's something like photographic stacking.

Yes, the best HDR algorithms derive the weights (i.e., the respective alpha channels) from the luminosity ratios in the constituent images.

That's their ESTAR base, Kodak's trade name for polyester -- aka DuPont's Mylar. The emulsion is actually the same, but the base (which is nearly all of the film's thickness) can be much thinner because polyester is far stronger than cellulose acetate. It also has a much wider temperature range, something the Apollo deniers who think the film would have instantly frozen or melted ought to know.

The rest of the story is that ESTAR was developed first for Project CORONA and was quite secret until NASA had similar needs and the decision was made to declassify ESTAR but not to publicly announce its secret use.  ESTAR was developed for use in space, and has since been adaptable to other applications.

Kodak points out an interesting drawback to ESTAR. It's so strong that a film jam can damage a camera or projector.

Well, yes and no.  The thicknesses of ESTAR provided commercially up until the virtual demise of Kodak's film business was substantially thicker than that provided for CORONA and Apollo.  When the museum I volunteer at was preparing an aerial photography exhibit in connection with their acquisition of an SR-71 Blackbird, we located several CORONA-era cameras, one of which was still loaded with (lightstruck) original ESTAR film.  It is very thin, and -- these days -- quite fragile.  The next time I'm up there, I'll see if I can either obtain a sample or measure it with a micrometer.

I think Ektachrome had been around for a while before Apollo; my dad shot a lot of slide film in the late 1950s and early 1960s and a lot of it is Ektachrome.

The "Ektachrome" name refers to a number of related emulsions.  I most recently shot on E-6.  The Apollo photography was done on E-3.  Your dad may have shot on E-3 or one of the earlier emulsions/processes.

I was somewhat surprised that NASA chose Ektachrome as it's notorious for fading, with images going red due to fading of the cyan dye.

That has happened.  Michael Light has inspected the camera originals and noted significant shifts toward magenta in several rolls.  This is notwithstanding exemplary storage and handling (but see below).

And as you say, Ektachrome had the advantages of higher speed, wider exposure latitude and much simpler processing that's harder to screw up.

Sadly some of it was screwed up.  While the E-3 process is straightforward, it also affords expert lab technicians more latitude in processing to correct problems, and some of these methods were applied to some Apollo rolls and has affected their longevity.  Again I recall Michael Light often touches on these in his lectures.  The plan was to select a film that didn't require expert photographers, but did require expert lab techs, the theory being that the darkroom wizards would jump in and do their thing if the astronaut-photographers screwed up.

[chrisbobson]

Why are there no stars seen on the pictures of the moon?

mabye it was the technology at that time or is their another reason?  ???Please explain.

Cody, most  students of the hoax who claim they are serious focus on the fact that the astronauts tend to seldom discuss stars, discount them, not that they are not in photos. 

[Andromeda]

Why are there no stars seen on the pictures of the moon?

mabye it was the technology at that time or is their another reason?  ???Please explain.

Cody, most  students of the hoax who claim they are serious focus on the fact that the astronauts tend to seldom discuss stars, discount them, not that they are not in photos.

[citation needed]

[chrisbobson]

Why are there no stars seen on the pictures of the moon?

mabye it was the technology at that time or is their another reason?  ???Please explain.

Cody, most  students of the hoax who claim they are serious focus on the fact that the astronauts tend to seldom discuss stars, discount them, not that they are not in photos.

[citation needed]

Citation from the students or the astronauts.  As far as the latter goes, check out the famous armstrong comments.  We all know them.  As far as the students go, you agree or do not.  It is subjective.  Guess you could pole HBs and ask them about this and how much time they spend on the subject as well.  I think it is solid such as something subjective like this can be.  That perspective certainly shows a greater level of understanding than the case wherein the HB says, "where are the stars in the pics?"

[Mag40]

Why are there no stars seen on the pictures of the moon?

mabye it was the technology at that time or is their another reason?  ???Please explain.

Cody, most  students of the hoax who claim they are serious focus on the fact that the astronauts tend to seldom discuss stars, discount them, not that they are not in photos.

Incorrect....on both the statement and its inherent claim. Surely you aren't going to start with the Armstrong-Moore interview again are you?

http://www.last-word.com/content_handling/show_tree/tree_id/4500.html

Go back.....read the first reply. Your subsequent reply to it was scarily obsessive.

[chrisbobson]

Why are there no stars seen on the pictures of the moon?

mabye it was the technology at that time or is their another reason?  ???Please explain.

Cody, most  students of the hoax who claim they are serious focus on the fact that the astronauts tend to seldom discuss stars, discount them, not that they are not in photos.

Incorrect....on both the statement and its inherent claim. Surely you aren't going to start with the Armstrong-Moore interview again are you?

http://www.last-word.com/content_handling/show_tree/tree_id/4500.html

Go back.....read the first reply. Your subsequent reply to it was scarily obsessive.

No big stake in it.  My point was simply no stars in the pics is no point, a non starter.