APOD: Apollo 17 at Shorty Crater (2012 Jun 24)

[APOD Robot]

Apollo 17 at Shorty Crater

Explanation: In December of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon in the Taurus-Littrow valley, while colleague Ronald Evans orbited overhead. This sharp image was taken by Cernan as he and Schmitt roamed the valley floor. The image shows Schmitt on the left with the lunar rover at the edge of Shorty Crater, near the spot where geologist Schmitt discovered orange lunar soil. The Apollo 17 crew returned with 110 kilograms of rock and soil samples, more than was returned from any of the other lunar landing sites. Now forty years later, Cernan and Schmitt are still the last to walk on the Moon.

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[Boomer12k]

Shorty Crater?????? WHICH PART??????

The rover and Schmitt look so small in the picture...it's a lonely place...

:---[===] *

[scr33d]

This brings to mind of Clarke's A Fall of Moondust, with the steep grade and the rover so close to the edge...

[scr33d]

Speaking of dust, why the use of soil to refer to lunar regolith?

[Mactavish]

The full panorama is even more spectacular!

Click to view full size image

[SF_Cass]

Why do no stars appear in the night sky of this image?

[deathfleer]

It is haunting me and perplexing me: Is that giant ball falling or floating away. by how much

[owlice]

Why do no stars appear in the night sky of this image?

Because it's not night; it's day.

[Ann]

Why do no stars appear in the night sky of this image?

It's because the Sun was shining on the Moon when this picture was taken. The Sun is very high in the sky in today's APOD: note how short the shadows are! Please note that the "underside" of that Moon vehicle is in shadow.

Yes, the sky is black in today's APOD. The lunar sky is always black, because the Moon has no atmosphere. But when the Sun is up, it shines more brilliantly than it does on the Earth. That is precisely because the Earth has an atmosphere, and some of the sunlight is scattered in the Earth's atmosphere, diluting the Sun's most intense glare. On the Moon the Sun is like an unbelievably white-hot spotlight in the black sky. The contrast between brightness and darkness becomes intolerable. Even if you look away from the Sun, the contrast between the brilliantly lit-up lunar landscape and the black sky is so great that the faint stars are completely drowned out.

Click to view full size image

Have you heard about light pollution? The scene in today's APOD is so light-polluted by brilliant sunlight that a camera set to record details in the astronaut, the lunar vehicle and the lunar landscape can't possibly pick up the faint, faint pinpricks of the stars in the black sky.

Take a look at this picture of an earthly city at night. The brilliantly lit buildings are seen against the black sky. But where are the stars?

Ann

[no one]

What Magnitude star would have been necessary to have been visible in the photo??
You can estimate the f-stop and time for the exposure if the documentation is unavailable.

[Giordano Bruno]

We are told they walked on the Moon between 12 and 14 of december 1972. On Taurus-littrow Valley .

It was Moon's first quarter as seen from Earth.

Seen from Taurus Littrow Valley on the Moon's terminator , it was rising sun.

Remember revolution of the Moon on its axis takes 28 days. So does Moon's revolution around the Earth. Thus a Moon's day lasts 28 Earth days.

The picture shows overhead illumination .

The question is : How possibly can light shine from overhead and cast so short shadows on the picture ???

Think about it.
Keep interrogating the pictures with open eyes with open mind .
Remember :

" The bigger the lie, the more it will be believed. " ( quoted from Gooebbels, Ministry of Hitler.)

[owlice]

The question is : How possibly can light shine from overhead and cast so short shadows on the picture ???

The same way it does on Earth. Go outside at astronomical noon and check to see how long your shadow is.

My Shadow

I HAVE a little shadow that goes in and out with me,
And what can be the use of him is more than I can see.
He is very, very like me from the heels up to the head;
And I see him jump before me, when I jump into my bed.

The funniest thing about him is the way he likes to grow—
Not at all like proper children, which is always very slow;
For he sometimes shoots up taller like an India-rubber ball,
And he sometimes gets so little that there’s none of him at all.

He hasn’t got a notion of how children ought to play,
And can only make a fool of me in every sort of way.
He stays so close beside me, he’s a coward you can see;
I’d think shame to stick to nursie as that shadow sticks to me!

One morning, very early, before the sun was up,
I rose and found the shining dew on every buttercup;
But my lazy little shadow, like an arrant sleepy-head,
Had stayed at home behind me and was fast asleep in bed.

[neufer]

[b][color=#0000FF]Eugene Cernan (w. shadow) on the lunar surface, December 13, 1972.[/color][/b]

---

The question is : How possibly can light shine from
overhead and cast so short shadows on the picture ???

Back-lighting

Art Neuendorffer

He hasn’t got a notion of how children ought to play,
And can only make a fool of me in EVERy sort of way.

[Case]

How possibly can light shine from overhead and cast so short shadows on the picture?

When the first Apollo 17 EVA started, the Sun was 16° high in the sky. That would make shadows 3.5 times longer than the height of an object.
When the third and last EVA ended, then Sun was 41° high in the sky. That should make shadows only 1.1 times longer that the height of an object.

I've combined two graphs into one, to show the relation between altitude of the Sun and the length of shadows. (I hope it doesn't add confusion.)
The times come from the Apollo 17 Timeline.
The corresponding Sun altitudes come from Stellarium.
The shadow lengths come from the formula L = h / tan(α), with h=1 to get a multiplier for any height.

[Giordano Bruno]

Thank you, Case,for your clear and documented mathematical explanation.

I understand the shadow of anything standing on Moon's Taurus Valley between 12 and 14 december 1972 should cast a shadow at least as long as the height of the objet itself.

Which is not the case on the picture presented.

" There is a mystery or a lie " . ( quoted from Inspector Columbo )

Daring to face strongly a single fact is sometimes the path leading from illusion to truth.

That would really be " a small step for man ,but a giant leap for mankind "

[Chris Peterson]

The picture shows overhead illumination .

This is your error. The photo does not show overhead illumination. The Sun is behind and to the left of the photographer, and the shadows are pointing as expected. You can easily see the long shadow of the rover around the wheels... if the illumination were overhead, you wouldn't see the shadows of the wheels at all.

Of course, it's always difficult figuring out where the Sun is just by looking at shadows, either on the Earth or the Moon. Many images cover a wide enough angle that the direction of shadows varies substantially from one side to the other, and on hilly terrain direction and length is strongly influenced by the slope of the ground.

Google images for Apollo 17 and you'll see that most show long shadows, indicative of the Sun being low in the sky.

[geckzilla]

There's nothing wrong with the lighting in the moon photos. If you think there is, you are confused. There's no mystery to it at all. Enough insinuating. If you think the moon landings are a hoax, just say so and I can remove your post and ban your IP promptly because arguing with you is like arguing with someone who has a brain tumor.

[Chris Peterson]

I understand the shadow of anything standing on Moon's Taurus Valley between 12 and 14 december 1972 should cast a shadow at least as long as the height of the objet itself.

Which is not the case on the picture presented.

Only because you are failing to interpret the image correctly.

You are also overlooking the fact that much of this image appears to show an area sloped towards the Sun, which raises its apparent height, and that when the Sun is behind you, objects in front cast shadows that- from your perspective- appear to have nearly the same cross-section as the objects themselves.

[neufer]

I understand the shadow of anything standing on Moon's Taurus Valley between 12 and 14 december 1972 should cast a shadow at least as long as the height of the objet itself.

Which is not the case on the picture presented.

" There is a mystery or a lie " . ( quoted from Inspector Columbo )

The sun is behind the photographer such that the elongated shadows are either foreshortened or hidden by the objects themselves.

Inspector Jacques Clouseau: There is a time to laugh and a time not to laugh, and this is not one of them.

[Chris Peterson]

What Magnitude star would have been necessary to have been visible in the photo??
You can estimate the f-stop and time for the exposure if the documentation is unavailable.

Venus (mag -4) occasionally shows up in lunar images, and images of the Earth from ISS.

[Chris Peterson]

Yes, the sky is black in today's APOD. The lunar sky is always black, because the Moon has no atmosphere. But when the Sun is up, it shines more brilliantly than it does on the Earth. That is precisely because the Earth has an atmosphere, and some of the sunlight is scattered in the Earth's atmosphere, diluting the Sun's most intense glare. On the Moon the Sun is like an unbelievably white-hot spotlight in the black sky.

That's technically correct, but the actual increase in brightness of the Sun as seen from the Moon is less than a magnitude compared with Earth. Physiologically, the Sun appears no brighter when seen from the Moon or from space.

The contrast between brightness and darkness becomes intolerable. Even if you look away from the Sun, the contrast between the brilliantly lit-up lunar landscape and the black sky is so great that the faint stars are completely drowned out.

Photographically, that's certainly true. But the lunar surface is about the same color and reflectivity as coal, so it reflects less light than most ground on the Earth. The astronauts reported that they could see stars if they were out of the direct light. The biggest problem for them in this regard was the filters in their helmet visors. They were basically wearing super sunglasses.

[neufer]

Apollo 17 at Shorty Crater

The image shows Schmitt on the left with the lunar rover at the edge of Shorty Crater,
near the spot where geologist Schmitt discovered orange lunar soil.

• The great fall of the offwall entailed at such short notice the pftjschute of Finnegan,
  erse solid man, that the humptyhillhead of humself prumptly sends
  an unquiring one well to the west in quest of his tumptytumtoes:
  and their upturnpikepointandplace is at the knock out in the park
  where oranges have been laid to rust upon the green since devlinsfirst loved livvy.

[neufer]

[b][color=#0000FF]The actual increase in brightness of the Sun as seen from the Moon about 36% (i.e., a third of a magnitude) brighter than a noon day Sun as seen from Earth.[/color][/b]

---

The lunar sky is always black, because the Moon has no atmosphere. But when the Sun is up, it shines more brilliantly than it does on the Earth. That is precisely because the Earth has an atmosphere, and some of the sunlight is scattered in the Earth's atmosphere, diluting the Sun's most intense glare. On the Moon the Sun is like an unbelievably white-hot spotlight in the black sky.

That's technically correct, but the actual increase in brightness of the Sun as seen from the Moon is less than a magnitude compared with Earth. Physiologically, the Sun appears no brighter when seen from the Moon or from space.

[eltodesukane]

In December of 1972, Apollo 17 ... ... almost 40 years ago.

[rigelan]

Man, what an experience to actually walk the edge of the crater on the moon!