FAR SIDE OF THE MOON

[tarkus]

It is not adequate. You have been asked the same question repeatedly by me several times, and the same subject has been discussed by others. In the time it has taken you to write these responses and drag more arguments to the table you could have answered the one simple question: how big will Earth appear to be from 800,000 km?

Half of the little land of the moon picture. The giant gif Earth is disproportionate.

But you waited until now to acknowledge your mistake. Why?
So why has it taken you so long to acknowledge your mistakes and errors when they have been pointed out to you so many times?

better late than never, right? I have the impression that you are only looking the fight.

With respect to gif Pluto, it is assumed that these images are obtained by the probe as it approaches the planet,

Why assume anything? The source of the images is freely available online.

I say assume because NASA does not always tell the truth ... and often says things that make no sense, but do not be offended because NASA is not God.

a distant object should be small, but as it approaches should be growing in size,

It is growing in size. But if it starts out at 3 pixels wide, how many pixels wide will it have to be before it doesn't look blurry?

If the idea is to show how a planet is becoming bigger as time the observer is approaching, why the size of each image is increased until it blurred or pixelated?
One is that I bring it now, it makes no sense to show a planet of this size in such a blur, it seems like a joke.

it makes no sense to publish blur and even pixilated, especially if one wants to try something

Wrong. Even a blurred image tells us new things. Who knew before the pictures were published that Pluto's moon Kerberos has two lobes?  Even with a blurred image we have learned a significant fact we didn't know before. Only laymen think all images should be crisp and detailed to be of value.

You can believe what you want, but this is an inexplicable shit, it is preferable to see a planet three times smaller and well defined that this crap blurred and out of focus.
You seem blinded by hate, hard to believe that a lover of astronomy can feel satisfied with a photographic material so horrible.

I do not know if this image was obtained by the CSM as it orbited the Moon or LM,

Neither. It was taken on the return journey to Earth, from some considerable distance.

That is impossible because the image is the hidden side of the Moon, have you forgotten? what that means is the Apollo spacecraft traveling in the opposite direction to Earth, but that possibility does not appear in the NASA flight plan, then?

[ka9q]

Half of the little land of the moon picture. The giant gif Earth is disproportionate.

This doesn't answer the question. We want to know the angular size of the earth when seen from a distance of 800,000 km. Do you understand the question?

One is that I bring it now, it makes no sense to show a planet of this size in such a blur, it seems like a joke.

If you don't like pictures with enlarged pixels, you are always free to bring it up in Photoshop or Gimp and reverse the process. You'll end up with a black frame and a tiny dot, but that's your preference.

That is impossible because the image is the hidden side of the Moon, have you forgotten? what that means is the Apollo spacecraft traveling in the opposite direction to Earth, but that possibility does not appear in the NASA flight plan, then?

You don't seem to understand orbital mechanics, which isn't surprising -- many people don't.

The trans-earth injection (TEI) burn was conducted on the far side of the moon, just as the trans-lunar injection (TLI) was conducted on the far side of the earth, away from the moon. As Apollo then came back around to the near side of the moon, it climbed away from it. So after TEI the astronauts saw (and photographed) a moon that, as it receded, first showed mostly the far side and then a combination of the far and near sides, limited of course by solar illumination. And that's exactly what we see in those photographs.

[Sus_pilot]

It is not adequate. You have been asked the same question repeatedly by me several times, and the same subject has been discussed by others. In the time it has taken you to write these responses and drag more arguments to the table you could have answered the one simple question: how big will Earth appear to be from 800,000 km?

Half of the little land of the moon picture. The giant gif Earth is disproportionate.

Wide angle vs. telephoto. 

Instead of trying to understand the math, you might try a good book on photo composition.  If you can get your hands on the Life magazine book series on photography, you'll learn a lot of the practical applications.

[onebigmonkey]

I say assume because NASA does not always tell the truth ... and often says things that make no sense

It seems to me that this is the crux of your argument, as with many others arguing your point of view. For reasons best known to yourself you have decided that NASA tells lies. It is a false and ridiculous position from which to argue.

That is impossible because the image is the hidden side of the Moon, have you forgotten? what that means is the Apollo spacecraft traveling in the opposite direction to Earth, but that possibility does not appear in the NASA flight plan, then?

Which part of the flight plan did not include returning home again? Your point may have been lost in translation, but it makes no sense.

Go look at the entire sequence of images, you will see that photographs increasingly reflect the view that you see from Earth as it gets closer to it and the curve of the craft's trajectory points it towards a point that intersects Earth's orbit. Try not to think of that trajectory as a straight line but a curve.

This is not a difficult concept to grasp, and you can easily prove it to yourself by looking at the images. Luckily for you, some of us are prepared to put the work in, and here is the sequence from that magazine that I did for my site:

It's on this page http://onebigmonkey.com/apollo/sides/sideways.html

[Jason Thompson]

Half of the little land of the moon picture.

That is not what I asked. I asked what the angular size will be from 800,000 km. It is 2 degrees wide from 400,000 km, so how big will it look, in degrees, if you move to 800,000 km? Do you mean by your answer 'half the little land' that it will appear 1 degree wide?

The giant gif Earth is disproportionate.

The two images were taken with completely different equipment, so you cannot expect the Earth to take up the same size in the image from the two sources.

better late than never, right?

Indeed, but why wait until so late?

I have the impression that you are only looking the fight.

No, I am holding you to common courtesy when discussing things. When you make mistakes and they are pointed out to you it is generally considered polite to acknowledge that rather than try and move on as though it didn't happen.

I say assume because NASA does not always tell the truth

So that's your justification for just making stuff up and then being upset when NASA doesn't conform to your expectations?

If the idea is to show how a planet is becoming bigger as time the observer is approaching, why the size of each image is increased until it blurred or pixelated?

How big is 1 pixel? You either have a tiny image or a large blurred one, but neither has more detal. The level of detail is determined by the number of pixels the planet takes up.

it is preferable to see a planet three times smaller and well defined that this crap blurred and out of focus.

The size of the image doesn't make a difference. There is no more detail or definition in a small image that is only 50 pixels wide than there is in a magnified image of something that was only 50 pixels wide on the original image.

You seem blinded by hate,

I'm not the one desperately clinging to the idea that NASA is some conspiracy-driven organisation lying to the world.

hard to believe that a lover of astronomy can feel satisfied with a photographic material so horrible.

It's also hard to believe someone can't manage a straight answer. Now, can you clarify: do you mean to say that the Earth will appear one degree wide from 800,000 km when you say 'half the little land o the Moon pic'?

That is impossible because the image is the hidden side of the Moon, have you forgotten?

No, I haven't. Orbital mechanics dictates that the spacecraft spends some time moving away from the Moon on the far side before it swings round to head towards Earth. It didn't just fly in a straight line between the two objects.

[smartcooky]

I am coming to realise that either tarkus really has no understanding or conceptualisation of perspective, or he is pretending he doesn't understand so that he can keep arguing.

[Apollo 957]

That is impossible because the image is the hidden side of the Moon, have you forgotten? what that means is the Apollo spacecraft traveling in the opposite direction to Earth, but that possibility does not appear in the NASA flight plan, then?

No, as others have pointed out, you need to start accelerating whilst on the far side, so that you reach the required speed when Earth (or, more crucially, the point where Earth will be as you finish the journey) comes into view.

Remember, as I pointed out to you before - both the Earth and the Moon are moving as you do this,  it's not a journey between two stationary points. This will also be a factor in where the craft is when the TEI starts. 

Tell us which 'flight plan' you've been looking at, please....

[Paul]

Half of the little land of the moon picture. The giant gif Earth is disproportionate.

tarkus - you STILL haven't read any basics of photography or basics of geometry/trigonometry books have you?

The relative sizes of objects depends on their physical size AND their distance from the camera. The field of view is determined by the focal length of the camera.

Where you see the phrase "focal length" perhaps you can substitute the word "zoom", does that make it easier to understand? So on an 18-200mm zoom lens for example, 18mm is "zoomed out" (wide field of view and everything smaller), 200mm is "zoomed in" (narrow field of view - everything bigger).

In the first image, the Earth is 'small' because a wide-angle lens has been used (70mm?). I could find out the actual focal length if you'd indicated the reference number for this image (apologies if you did that earlier in the thread). Others will know I'm sure.

In the second image, the Earth is 'large' because the camera lens is a 2,800mm focal length telescope with a FOV of 0.6 degrees http://www.nesdis.noaa.gov/DSCOVR/pdf/DSCOVR%20-%20EPIC%20Instrument%20Info%20Sheet.pdf. As explained many times, the Moon is 'small' in this image because the photo is taken from 1,000,000 miles from the Earth (and the relative sizes are determined by their physical size and their distance from the camera).

[Zakalwe]

Half of the little land of the moon picture. The giant gif Earth is disproportionate.

Sometimes you get a little window into someone's true abilities, and after you posted this ^^, all I can say is WOW! You really do know absolutely nothing about photography, do you?

Ages ago I asked you a question: http://www.apollohoax.net/forum/index.php?topic=988.msg33948#msg33948 Now i know why you can't answer it...you have no idea about the most basic things in photography.

I say assume because NASA does not always tell the truth ... and often says things that make no sense, but do not be offended because NASA is not God.

a distant object should be small, but as it approaches should be growing in size,

It is growing in size. But if it starts out at 3 pixels wide, how many pixels wide will it have to be before it doesn't look blurry?

Repeating the claim does not make it any less incorrect. Have you done any research yet since I posted this?

Tarkus, go and find out the distance that each image in the gif were taken from. Then find out the imager specifications (number of pixels, sensor size, well depth, QE efficiency), the optical train specifications (focal length, aperture and focal speed). Then find out the post-processing procedures (Dark frame subtraction? Bias frame calibration? Flat frame calibration?). Once you have all of this, then tell us why the images are wrong.

That is impossible because the image is the hidden side of the Moon, have you forgotten? what that means is the Apollo spacecraft traveling in the opposite direction to Earth, but that possibility does not appear in the NASA flight plan, then?

Another "tell", which shows that you have no idea. It seems that you think that Apollo flew directly to the Moon, which is probably why you wanted to see the astronauts sitting at the controls driving there. Given your inability to understand simple perspective and your obvious problems with spatial reasoning, I bet that you think that the shortest distance to the Moon is a direct line? I think that you are struggling to comprehend that the universe is in 3D, to be honest.

Here's an excellent gif from Bob Braeunig's site: http://www.braeunig.us/apollo/hybrid-profile.htm



I'm willing to wager that you had no idea that the trajectory looked like this.

[onebigmonkey]

The LM & Earth image is from Apollo 17

http://www.lpi.usra.edu/resources/apollo/frame/?AS17-134-20463

and the focal length is indeed 70mm

[Apollo 957]

I'm willing to wager that you had no idea that the trajectory looked like this.

I'm a little surprised at Earth being portrayed as static in space, but is this accounted for by the mechanics of the Earth/Moon system being locked in one orbit around the Sun?

I had pictured the CM 'aiming' for a point in space where Earth would arrive at the end of the journey; which seems to be portrayed in the arrival at the Moon on the outward journey.

[Allan F]

It's just a matter of selecting the proper coordinate system. It is simpler to view the trajectory in an Earth-centered coordinate system than in a Sun-centered one.

[bknight]

Half of the little land of the moon picture. The giant gif Earth is disproportionate.

The left picture was taken over 45 years ago from 2380000 miles from the earth, the right is taken very recently from 1000000 with different cameras they will not compare size wise

But you waited until now to acknowledge your mistake. Why?
So why has it taken you so long to acknowledge your mistakes and errors when they have been pointed out to you so many times?

better late than never, right? I have the impression that you are only looking the fight.

With respect to gif Pluto, it is assumed that these images are obtained by the probe as it approaches the planet,

Why assume anything? The source of the images is freely available online.

I say assume because NASA does not always tell the truth ... and often says things that make no sense, but do not be offended because NASA is not God.

Why do you ASSUME this, it is your opinion, not based on factual evidence.

That is impossible because the image is the hidden side of the Moon, have you forgotten? what that means is the Apollo spacecraft traveling in the opposite direction to Earth, but that possibility does not appear in the NASA flight plan, then?
[/quote]

As others have stated the TEI burn happened on the side of the moon sway from the earth and the trajectory is a curve away from the moon, giving the montage that you see.  Notice in the montage the moon rotating.

[bknight]

I'm willing to wager that you had no idea that the trajectory looked like this.

I'm a little surprised at Earth being portrayed as static in space, but is this accounted for by the mechanics of the Earth/Moon system being locked in one orbit around the Sun?

I had pictured the CM 'aiming' for a point in space where Earth would arrive at the end of the journey; which seems to be portrayed in the arrival at the Moon on the outward journey.

The earth isn't static as you know, but the animation with a moving source point would have been more difficult.

[Paul]

ok, tarkus, try this...

We know that the Moon and the Sun appear the same relative size from Earth, hence a Solar Eclipse when the Moon passes between the Earth and Sun.  So let's test out the trigonometry on that using an online calculator (while using the calculator perhaps you could answer Jason's long standing question...):

Sun
Size: 1,392,000 km diameter
Distance from Earth: 152,000,000 km (at aphelion)
http://sizecalc.com/#distance=152000000kilometers&physical-size=1392000kilometers&perceived-size-units=degrees
Apparent size = 0.525 degrees

Moon
Size: 3474 km diameter
Distance from Earth: 384,400 km
http://sizecalc.com/#distance=384400kilometers&perceived-size=0.517805degrees&physical-size-units=kilometers
Apparent size = 0.518 degrees

The two numbers match to a hundredth of a degree, so we have proved that you can measure relative size of astronomical objects using trigonometry, do you agree?

So let's turn to the NASA animation:

Moon
Size: 3,474 km diameter
Distance from DSCOVR:  1,520,830 - 384,400 = 1,136,430 km
http://sizecalc.com/#distance=1136430kilometers&physical-size=3474kilometers&perceived-size-units=degrees
0.17515 degrees

Earth
Size: 12,742 km diameter
Distance from DSCOVR: 1,520,830 km
http://sizecalc.com/#distance=1520830kilometers&perceived-size=0.48004degrees&physical-size-units=kilometers
0.48004 degrees

Compare relative sizes:
Moon/Earth size ratio (using trigonometry) = 0.17515 / 0.48004 = 0.365 = 36.5%
Moon/Earth size ratio (pixel sizes from animation) = 164 pixels / 448 pixels = 0.366 = 36.6%

Therefore, animation is totally consistent with our calculations. The relative Moon and Earth sizes are exactly what we would expect.


If you want to further prove to yourself that relative size calculations can work at any distance, no matter whether close or astronomical then let's link those two items up.

All you need to do is go outside with a 67mm tennis ball (or other similar sized spherical object). Place it on a fence post or table edge, and then step back 7.4 metres. My crystal ball predicts that if you line up the tennis ball with the Moon you will get a Tennis Eclipse...
(Here's the crystal ball by the way: http://sizecalc.com/#physical-size=67millimeters&perceived-size=0.518degrees&distance-units=meters)

Move further back and Moon will become visible from behind the tennis ball (and thus LARGER in relative terms compared to the tennis ball). Move further forward and Moon will be totally hidden by the tennis ball (and the Moon will become smaller in comparison to the tennis ball).

After doing this please come back and confirm that you now understand how distance from observer determines relative object sizes and that it applies at all distances, and that the NASA animation is totally correct.