Blue glow

[Trebor]

Question, in many of the images in AS12-46 there is a blue glow around brightly lit objects (for example : AS12-46-6826).
It looks like a result of the over-exposed object but why is it a halo-like blue glow?

[raven]

This is also something I have wondered about. It came up recently in a youtube discussion, and I honestly had no real answer.

[Echnaton]

This is something that an experienced photographer could bring into focus, but my immediate thought was that the lens was dirty.

[ipearse]

Comment in the NASA images site says it's due to a dust smudge on the lens. http://www.hq.nasa.gov/alsj/a12/images12.html#6826

Edit: Looking at the images on that magazine, you can see evidence of the smudge starting around 6813 and going through to at least 6852.

[Trebor]

Comment in the NASA images site says it's due to a dust smudge on the lens. http://www.hq.nasa.gov/alsj/a12/images12.html#6826

Edit: Looking at the images on that magazine, you can see evidence of the smudge starting around 6813 and going through to at least 6852.

That would make sense with the more intense light from the astronaut making the effect more obvious.

[JayUtah]

Smudge.  Blue light scatters more readily than red light, so halos created by scatter through lens contamination will often appear blue.

[ka9q]

And in the same series of Apollo 12 images, the ALSJ notes that darker objects in the center of the image (i.e., behind the dust spot) appeared reddish. That's consistent with the blue light having been scattered out of the light from the subject.

The blue glow appeared around bright objects like space suits, not on the suits themselves. They were so bright that they probably saturated the film which is why they still appeared white despite having some of their blue scattered out.

[Glom]

There are numerous examples of exposure bleeding in some of those ALSEP setup shots which testify to that.

One particularly good one looks at Bean cross-sun with a crosshair over his legs. The sunlit half of his legs have bled out the crosshair while the part over the shadow side can still be seen. It's a great rebuttal to the crosshairs argument. (the one I'm talking about is in Michael Light's book Full Moon)

[ka9q]

Trivia regarding Apollo 12 - did you know that they accidentally left an exposed film magazine on the lunar surface? Somehow they lost count, or changed the nomenclature at the last minute such that their checklists didn't catch it.

I always wondered what pictures were on that magazine. Percy and the other deniers are probably right in that if we could retrieve that magazine today, it would probably be ruined by heat and radiation. After 42+ years.

[Glom]

Trivia regarding Apollo 12 - did you know that they accidentally left an exposed film magazine on the lunar surface? Somehow they lost count, or changed the nomenclature at the last minute such that their checklists didn't catch it.

I always wondered what pictures were on that magazine. Percy and the other deniers are probably right in that if we could retrieve that magazine today, it would probably be ruined by heat and radiation. After 42+ years.

Those two were useless.  First, they destroy the television camera.  Then they smudge the camera lens on one of the Hasselblads.  Then they leave a magazine on the surface.

[Hal]

Those two were useless.  First, they destroy the television camera.  Then they smudge the camera lens on one of the Hasselblads.  Then they leave a magazine on the surface.

I'd hesitate to call anyone who managed to put their boots on the moon "useless," but now that you mention it, they also failed to pull off their surprise "group shot," when they misplaced the self-timer device they'd smuggled along.  :/

[ka9q]

Those two were useless.  First...

Oh, come on. They were easily the most entertaining lunar crew of the entire Apollo program. Pete Conrad lines like "That may have been a small one for Neil, but it was a big one for me" were real gems.

[gillianren]

There's a reason for the casting of Dave Foley in From the Earth to the Moon, certainly.

[Glom]

Stop taking me so seriously. Apollo 12 is my favourite mission.

[VincentMcConnell]

Stop taking me so seriously. Apollo 12 is my favourite mission.

Same with me. Apollo 12 was literally the best. You should watch the Apollo 12 section of "From the Earth to the Moon". It's so awesome.

On topic:
I'm kind of necro'ing this post, but I haven't been in on the action lately and so I'm just catching up. That's a really cool effect. Like people already said, it's a dust smudge, but light has really awesome qualities where you never know what may have caused it.