[rottingroom]

Seriously your diagram is depicting what a ray of light from the moon is doing as observed for someone when the moon is directly overhead. Not someone who is seeing it shorty before the end of or shortly after the beginning of an eclipse.

[markjo]

Seriously your diagram is depicting what a ray of light from the moon is doing as observed for someone when the moon is directly overhead. Not someone who is seeing it shorty before the end of or shortly after the beginning of an eclipse.

That's why I keep asking him to show the umbra and penumbra.  The moon can stay totally eclipsed for an hour or more at a time.

[Tom Bishop]

Why do you have the blue line coming from the moon heading toward a point so far away from the observer? You point it to where it needs to be above the observer, where that ray of light enters a denser medium. You don't really have any conception of what is going on do you?

Do you mean, like this?

Tom, you have to add .5 degrees to both the sun's elevation and the moon's elevation.  Also, please make it a ray diagram so that you can see where the umbra and penumbra are (adjusted for refraction).

0.5 degrees doesn't help you and 1 degree doesn't help you.

In the video from the first post of this thread the moon is several moon-diameters above the horizon line. It is common knowledge that the moon takes up 0.5 degrees of the sky. So we can already see that the optical illusion explanation is bunk.

[rottingroom]

Why do you have the blue line coming from the moon heading toward a point so far away from the observer? You point it to where it needs to be above the observer, where that ray of light enters a denser medium. You don't really have any conception of what is going on do you?

Do you mean, like this?

Tom, you have to add .5 degrees to both the sun's elevation and the moon's elevation.  Also, please make it a ray diagram so that you can see where the umbra and penumbra are (adjusted for refraction).

0.5 degrees doesn't help you and 1 degree doesn't help you.

In the video the moon is several moon-diameters above the horizon line. It is common knowledge that the moon takes up 0.5 degrees of the sky. So we can already see that your "refraction" optical illusion is bunk.

No that is not what I mean. For purposes of making the diagram easier to understand you should start by making the observer on top of the earth especially since your refracted ray of light is being depicted from the side. This means we are talking about a ray of light coming from the moon (out of the rays that are coming from many directions from the moon) that is above the observer. It seems you don't get it so I will make you a proper diagram when I get the time.

[rottingroom]

Seriously your diagram is depicting what a ray of light from the moon is doing as observed for someone when the moon is directly overhead. Not someone who is seeing it shorty before the end of or shortly after the beginning of an eclipse.

That's why I keep asking him to show the umbra and penumbra.  The moon can stay totally eclipsed for an hour or more at a time.

That doesn't really help us, the shadow in the video is on the top which means that in this whole scenario the moon is slightly below the blue line that tom made. The error he is making is his peculiar choice for where he put the blue line. That is 1 ray of light that exists, but it isn't the ray of light that an observer experiencing a moon near the horizon is seeing unless he is showing a top down view, which is a peculiar choice for a diagram where we are trying to show refraction. 2d refraction diagrams are shown from the side. I don't think he did that though because he put the horizon on the top side of earth, so again, where is the ray of light that goes from the moon toward the earths top side?

[rottingroom]

Without being to scale, this is what I mean:





We need to use the appropriate ray of light.

Mine isn't to scale but I'm just trying to get the concept across for you.

[rottingroom]

To make matters even more strange, look at my diagram again. Some of the light from the sun that hits the moon is being refracted by the atmosphere on the bottom side of earth. Then the rays of light from the moon are refracted by the atmosphere on the top side of earth. Finally, the rays from the sun toward earth are also refracted by atmosphere on the top side too.

I'm actually pretty overwhelmed by how complicated this scenario is.

[rottingroom]

Actually, after looking at your corrected digram it does seem that you understand now. I was confused by your bigger circle (which is for measuring degrees) around your blue earth.

In any case your diagram didn't really demonstrate what happens to that refracted .5° ray of light when it enters the atmosphere. You'd need to zoom in.

I see claiming it doesn't work but not demonstrating it. At least we are making the large scale diagram correctly now but without a zoom here I don't see what this demonstrates.

[Yamato]

Someone needs to stop this.
The amount of nonsense by Sir Bishop is reaching epic heights

The astronomical refraction is about 1 minute of arc when the object observed is in a heigh far from the horizon, for example, the zenit.

When the object observed is near the horizon, the refraction can come up to 30 minutes of arc (0.5º). This is the "optimal" situation, since there are many factors than can make the refraction to change, such as pollution, humidity, and others. In a normal situation, you can estimate around 40 or 50 minutes of arc, and in worst conditions, you can expect up to 60 or 70 minutes of arc


In the video you show us, the moon seems pretty close to the horizon, the pollution is quite high, so it is perfectly possible that the moon has already been set minutes ago, so those 0.5 degrees that you think are nothing, are in fact a noticeable amount.

And if you want to know more about this: http://mintaka.sdsu.edu/GF/explain/atmos_refr/terrestrial.html

[rottingroom]

Another note. Refraction occurs when a ray of light goes from one medium to another. In this scenario the line that is separating the two mediums is curved and the point where it enters is far away from the observer on the horizon. This means that that line is not parallel with the earth underneath the observer. Because of this, the calculated half degree would need to be based off of whatever angle the ray of light from the moon hits the new medium as it enters. This makes it a lot more feasible for that half degree.

[Tom Bishop]

Without being to scale, this is what I mean:




We need to use the appropriate ray of light.

Mine isn't to scale but I'm just trying to get the concept across for you.

Another note. Refraction occurs when a ray of light goes from one medium to another. In this scenario the line that is separating the two mediums is curved and the point where it enters is far away from the observer on the horizon. This means that that line is not parallel with the earth underneath the observer. Because of this, the calculated half degree would need to be based off of whatever angle the ray of light from the moon hits the new medium as it enters. This makes it a lot more feasible for that half degree.

But the refraction you need is way more than 0.5 degrees.

Extending your refraction with a red line:


Adding protractor:

[rottingroom]

I see that you used my drawing where I did not make this to scale. If you would like to show the curved point in the imaginary line that separates the denser medium and the lighter medium of air then be my guest. I at least know that these calculations are far from simple. Not to mention that it isn't merely a case of two mediums. You are going from space into the atmosphere which gets progressively more dense as you get closer to the surface.

The part of the atmosphere where these rays enter the atmosphere is very far away too. Much further away than the horizon since it is some 80 miles or so above the surface of earth.

And again, remember the light we are seeing from the moon is the result of refracted light from the opposite side of the earth from the observer as well. This means that the moons position itself is also highly suspect.

[markjo]

Tom, if you look at your video again, you will notice that the lunar eclipse clearly begins at night and continues into the predawn twilight.  What evidence do you have that the sun is indeed above the horizon while the moon is significantly above the horizon?

[Tom Bishop]

I see that you used my drawing where I did not make this to scale. If you would like to show the curved point in the imaginary line that separates the denser medium and the lighter medium of air then be my guest. I at least know that these calculations are far from simple. Not to mention that it isn't merely a case of two mediums. You are going from space into the atmosphere which gets progressively more dense as you get closer to the surface.

The part of the atmosphere where these rays enter the atmosphere is very far away too. Much further away than the horizon since it is some 80 miles or so above the surface of earth.

And again, remember the light we are seeing from the moon is the result of refracted light from the opposite side of the earth from the observer as well. This means that the moons position itself is also highly suspect.

Here's a scaled model from http://andrewsteele.co.uk/physics/senseofscale/

"This image shows the Earth–Moon system to scale, with every pixel on the full-size image representing about 220 km."



Applying protractor we see that we require over 1 degree just to get to the horizon, let alone several moon diameters into the sky as seen in the video.



Not only that, the moon would have to be positioned a bit lower than it is in this image in order to get the shadows to match up and be lit from the bottom, as seen in the video.

We can clearly see that over 0.5 degrees is required, whichever way we put it.

Nor does it matter if this angle of refraction happens in the atmosphere "80 miles from the surface of the earth". The closer the starting point of the protractor gets to the moon, the bigger the angle will be.

[rottingroom]

I see that you used my drawing where I did not make this to scale. If you would like to show the curved point in the imaginary line that separates the denser medium and the lighter medium of air then be my guest. I at least know that these calculations are far from simple. Not to mention that it isn't merely a case of two mediums. You are going from space into the atmosphere which gets progressively more dense as you get closer to the surface.

The part of the atmosphere where these rays enter the atmosphere is very far away too. Much further away than the horizon since it is some 80 miles or so above the surface of earth.

And again, remember the light we are seeing from the moon is the result of refracted light from the opposite side of the earth from the observer as well. This means that the moons position itself is also highly suspect.

Here's a scaled model from http://andrewsteele.co.uk/physics/senseofscale/

"This image shows the Earth–Moon system to scale, with every pixel on the full-size image representing about 220 km."



Applying protractor we see that we require over 1 degree just to get to the horizon, let alone several moon diameters into the sky as seen in the video.



Not only that, the moon would have to be positioned a bit lower than in this image in order to get the shadows to match up and be lit from the bottom, as you demonstrated in your video.

We can clearly see that over 0.5 degrees is required.

Your argument relies on assumed position of the moon based on your best guess and the same for the sun which we do not see in the video. I do agree that your contentions are seemingly impossible if we assume what you've laid out in the op. But like markjo said, you've presented no evidence about where the sun is.

Please discover the definitions of dawn and dusk.

[Tom Bishop]

Your argument relies on assumed position of the moon based on your best guess and the same for the sun which we do not see in the video. I do agree that your contentions are seemingly impossible if we assume what you've laid out in the op. But like markjo said, you've presented no evidence about where the sun is.

Please discover the definitions of dawn and dusk.

We know where the sun is when the moon is fully eclipsed... it's directly behind the earth, lined up with the earth and moon.

Excuses that the sun is "also" refracted 0.5 degrees into the air are meaningless when we see that the required angles of refraction must be significantly more than a 0.5 degrees here and there for any of this to occur.

[rottingroom]

Your argument relies on assumed position of the moon based on your best guess and the same for the sun which we do not see in the video. I do agree that your contentions are seemingly impossible if we assume what you've laid out in the op. But like markjo said, you've presented no evidence about where the sun is.

Please discover the definitions of dawn and dusk.

We know where the sun is when the moon is fully eclipsed... it's directly behind the earth, lined up with the earth and moon.

Excuses that the sun is "also" refracted 0.5 degrees into the air are meaningless when we see that the required angles of refraction must be significantly more than a 0.5 degrees here and there for any of this to occur.

Oh, so you don't think this video depicts a selenelion?

I'm not making excuses, I've been hammering on about all the things that you haven't considered before you drew your initial conclusions in the op. If the moon is as high as it is in the video and if the sun hasn't even risen yet until the moon is much closer to the horizon toward the end of the video, then I don't see the problem. Since there is no evidence of what is going on with the apparent position of the sun other than the fact that it looks like dawn, then what else can be said?

[Rama Set]

Does anyone know if a Selenelion is defined as the moon being completely obscured by the horizon?  Or can half the moon be behind the horizon?  I ask, because that would also reduce the minimum refraction needed.

[Tom Bishop]

Your argument relies on assumed position of the moon based on your best guess and the same for the sun which we do not see in the video. I do agree that your contentions are seemingly impossible if we assume what you've laid out in the op. But like markjo said, you've presented no evidence about where the sun is.

Please discover the definitions of dawn and dusk.

We know where the sun is when the moon is fully eclipsed... it's directly behind the earth, lined up with the earth and moon.

Excuses that the sun is "also" refracted 0.5 degrees into the air are meaningless when we see that the required angles of refraction must be significantly more than a 0.5 degrees here and there for any of this to occur.

Oh, so you don't think this video depicts a selenelion?

I'm not making excuses, I've been hammering on about all the things that you haven't considered before you drew your initial conclusions in the op. If the moon is as high as it is in the video and if the sun hasn't even risen yet until the moon is much closer to the horizon toward the end of the video, then I don't see the problem. Since there is no evidence of what is going on with the apparent position of the sun other than the fact that it looks like dawn, then what else can be said?

We don't need to know the position of the sun behind the camera for this.

When the moon is eclipsed we know that the sun, earth, and moon are completely aligned. At this moment in the video we can see that the moon is several moon-diameters above the horizon line. I estimate over 4.5 moon diameters with a ruler. Knowing that the moon takes up 0.5 degrees of the sky, we can compute (0.5 x 4.5) that moon is over 2.25 degrees above the horizon.

Thinking back to the scaled model; if it takes over 1 degree of refraction just to get the moon to the horizon, and it must take an additional 2.25 degrees to get into its position into the sky, the moon must therefore be refracted at least 3.25 degrees to be where it is.

This is ignoring that the moon must be even lower than the last scaled model I posted depicts, beneath the earth's shadow, to account for it being lit from the bottom up.

Altogether, we see that the scenario is plainly impossible.

[Rama Set]

Why would it take something 0.5 degrees in diameter 1 degree to get to the horizon.  It would obviously take 0.5 degrees.