moon position

[Mona]

Given a photo of the moon, taken from Earth, is it possible to calculate approximate the position of the photographer's site?

[Waddensky]

If you know the altitude and the azimuth of the Moon, and the date: yes.

[Mona]

Ok, I don't know that. Is is possible to make exactly the same picture from 2 different locations?

[vlaiv]

1 hour ago, Mona said:

Ok, I don't know that. Is is possible to make exactly the same picture from 2 different locations?

Image of the moon taken at the same time from two different locations on the earth is probably going to be the same.

In theory with pixel analysis you could be able to tell something. Let's do some math to see how much difference would there be.

Moon is 384,400 km away and Earth has diameter of 12,740 km. Let's imagine that one photographer is at far east and other is at far west - so that distance between them is 12,740Km - not realistic scenario but it is upper bound - in reality, two photographers will certainly be closer.

This means that angular separation of two photographers is 1.8988°, or in another words - on sees the Moon from 1.8988° different angle.

Moon has circumference of 10,914.5 km, and on surface of the moon, angle of 1.8988° translates into 57.568 km.

Say that photographs are high res and are shot at 1 arc second per pixel (much higher resolution than the image posted above). 1 arc second in that image (1 pixel) corresponds to 1.8636 km in that image.

In the end we can calculate that feature in the center of the moon will be shifted by 57.568 / 1.8636 = ~31px.

That is actually something that we could detect. Here is diagram with exaggerated angles to explain principle:

If for example we have 3 times smaller image and 10 times less distance between photo sites 1 and 2 - then feature shift would be at most one pixel - and that is not something you can detect. For most part - you can't tell if image is shot from two different locations if it is shot at the same time under same conditions.

[Mona]

Thanks for your explanation.

I don't have the originals, I'm pretty sure that the picture above origanally belongs to NASA.
Now, is it possible that someone has taken the identical picture below, as far as I can estimate that it is identical?
In other words, is this picture below a fraud?
 

[Tiny Clanger]

11 minutes ago, Mona said:

Thanks for your explanation.

I don't have the originals, I'm pretty sure that the picture above origanally belongs to NASA.
Now, is it possible that someone has taken the identical picture below, as far as I can estimate that it is identical?
In other words, is this picture below a fraud?
 

I'm guessing someone on some social media or advert claims they took this photo themselves, and you doubt them ?

Ask them for the original image file and check the exif with one of the freely available tools. It is hidden information about when the image was taken, and with what camera.

Plenty of information about exif  out there, just do an online search.

[vlaiv]

7 minutes ago, Mona said:

Now, is it possible that someone has taken the identical picture below, as far as I can estimate that it is identical?
In other words, is this picture below a fraud?

These two are quite different images - one that you first posted and this other one.

Picture is certainly not fraud and to be honest - I don't really know what you mean by "fraud"?

In any case - processing is different in two images, they were not taken on the same date / time as illumination is different.

You can see from these two images that sun light is falling at a slightly different angle and thus illuminates marked region in "fraud" image a bit more than in Nasa one.

Why would you suspect that one image is fraud at all?

As Moon is on the orbit around the Earth - every 28 days or so - we get almost the same looking Moon - illumination is the same and everything (there are small differences in size and orientation due to libration, but in principle things are the same).

Two images taken months apart - but showing the same phase of the moon - will be remarkably similar if scaled to same size.

 

[Waddensky]

2 hours ago, Mona said:

Thanks for your explanation.

I don't have the originals, I'm pretty sure that the picture above origanally belongs to NASA.
Now, is it possible that someone has taken the identical picture below, as far as I can estimate that it is identical?
In other words, is this picture below a fraud?

Almost all NASA material is in the public domain, so fraud would only be possible if one claims to have made the photo.

Still, if you take the photo when the Moon is in the same phase (and this happens quite often), the photo will look very similar. Vlaiv's explanation is excellent.

I'm still not quite sure where you're at...