[SteelyBob]

Good point, and well made.

[reer]

All the talk about the Big Dipper, and which stars are visible, and when, may be interesting, but it leads us well away from my question, which is:

How does FE explain star trails that seem to dip almost vertically down to the horizon, instead of approaching it gradually, as they should in FET.

Here's another example:


Will those stars suddenly make an almost 90 degree turn as they approach the horizon?

[Tom Bishop]

Light is curing upwards in the FE model - https://wiki.tfes.org/Electromagnetic_Acceleration

Here is a rough star trail simulation of light curving upwards:

[Iceman]

In that video, the demonstration of modelled moon and star paths between about 7:24 and 7:40 show some curious rapid changes in angular separation of the moon and stars in the centre of the frame

[Tom Bishop]

There is undeniably some warping that doesn't happen in that simulation.

However, I don't think it's true that the stars and celestial bodies always maintain a constant angular diameter from each other in the sky. They slow down as they approach the horizon.

From the below video: "As you can see the stars get significantly closer together as they get closer to the horizon"



This is opposite from the star trail simulation, but there might be some wiggle room with the particular curve and angle and direction of light as it reaches the observer on the surface that causes it to slow down rather than to speed up. TBD.

[SteelyBob]

Light is curing upwards in the FE model - https://wiki.tfes.org/Electromagnetic_Acceleration

Here is a rough star trail simulation of light curving upwards:

At 6:44

Let us know if we are doing anything wrong

Well, ok...in the real star videos, as per all of the other ones, and indeed what you will see on any time-lapse footage of the stars, the stars appear to rotate in almost perfect circles - aside from the distortion you get when very close to the horizon from refraction, the stars motion is a circle, regardless of viewer location. In the video you've shown there Tom, the stars are not moving in concentric circles, but rather have some elliptical quality to them. Look at 6:44, and trace pairs of adjacent trails back and forth - they get closer together as they get lower in the sky. That's not what we observe when we look at the stars, and that's because the stars are many hundreds or thousands of light years away, meaning their distance from us is essentially constant regardless of where we are on earth, or where the earth is in its orbit. 

[Jay Seneca]

Not sure where this video was taken but you can see Ursa Major any time of the year and time of the night in all of the US. I live in southeast US around 30 latitude and I know this to be true. This shouldn’t be possible on RE.

You're right, it shouldn't be possible to see all of Ursa Major any time of the year and all night in all of the US. The 'big dipper', or the bit of Ursa Major that most people recognise, is visible from most of the states all year round, but only Dubhe, with a declination of 61, would be visible from 30 north all the time (because 30 + 61 > 90). The lowest star in the big dipper, alkaid, is at 49 degrees declination, meaning you'd need to be north of 41 degrees latitude for it to be circumpolar. At 30 north I'd expect most of Ursa Major to be below the horizon, especially in the winter.

If you're experiencing something different to that you are either a) looking for the wrong stars or b) in possession of one of the most earth-shattering observations made by a modern amateur astronomer, and you should definitely tell more people about it, because you could make some serious money out of it. You would be disproving every star almanac, every internet star calculator app...everything. You should start with a video, showing today's paper, some recognisable part of where you live so we can verify the location and then a picture of the whole of Ursa Major.

https://earthsky.org/tonight/where-is-the-big-dipper-on-these-octber-evenings

I look forward to seeing it.

I could show you some timestamp pictures throughout the night. That’s the easy part. The hard part would be proving my location without showing my location. 

[SteelyBob]

I could show you some timestamp pictures throughout the night. That’s the easy part. The hard part would be proving my location without showing my location.

Great, let's see the pics then - thanks.

[Tom Bishop]

Well, ok...in the real star videos, as per all of the other ones, and indeed what you will see on any time-lapse footage of the stars, the stars appear to rotate in almost perfect circles - aside from the distortion you get when very close to the horizon from refraction, the stars motion is a circle, regardless of viewer location. In the video you've shown there Tom, the stars are not moving in concentric circles, but rather have some elliptical quality to them. Look at 6:44, and trace pairs of adjacent trails back and forth - they get closer together as they get lower in the sky. That's not what we observe when we look at the stars, and that's because the stars are many hundreds or thousands of light years away, meaning their distance from us is essentially constant regardless of where we are on earth, or where the earth is in its orbit.

I haven't seen much evidence that the stars move in concentric circles.

From the pic in the OP, using a symmetrical circle tool:





Another pic:

[Longtitube]

I haven't seen much evidence that the stars move in concentric circles.

From the pic in the OP, using a symmetrical circle tool:


Another pic:

Your “symmetrical circle tool” isn’t drawing circles from the same centre each time, nor is it centered on the rotation centre of the sky in either image.

While we’re discussing photos of the stars, have you made sure these images were made with a perfectly rectilinear lens, one that was distortion-free? It would help your case to know.

[JSS]

I haven't seen much evidence that the stars move in concentric circles.

For the star trails to be perfect circles the lens can't have any significant distortion and must be perfectly aligned with one of the two pole stars, and that star must be in the center of the sensor.

For a lot of artistic shots this is not the case, and you will see visible distortion. This is not unusual, you see distortion in plenty of photographs. Taking pictures of the sky is no exception.

And as pointed out, you didn't draw your circles centered, so of course they are not going to line up.

This is a picture I took myself, with the camera centered on the North Star and using a lens with very little distortion. It's not perfect, I had it set on the roof of a house and the slow cooling during the night warped the trails slightly but as you can see, they are quite circular. I'd show some of my better ones, but for the same reason Jay gave, I do not want to give up my location here.

I've taken lots of pictures like this and can assure you they do move in circles.

[SteelyBob]

I haven't seen much evidence that the stars move in concentric circles.

I think you're missing the point. Look at 6:44 in the video, and then look at the photos in your post. The trails at 6:44 very clearly show a perspective effect - they are getting closer together as they get further away from the viewer. That's not what we see when we look at the stars.

[Tom Bishop]

It wouldn't make concentric circles because the stars slow down significantly as they approach the horizon.

There is undeniably some warping that doesn't happen in that simulation.

However, I don't think it's true that the stars and celestial bodies always maintain a constant angular diameter from each other in the sky. They slow down as they approach the horizon.

From the below video: "As you can see the stars get significantly closer together as they get closer to the horizon"



This is opposite from the star trail simulation, but there might be some wiggle room with the particular curve and angle and direction of light as it reaches the observer on the surface that causes it to slow down rather than to speed up. TBD.

And as pointed out, you didn't draw your circles centered, so of course they are not going to line up.

The star trails are too short in your example. And the point is to continue the curve, not center the circle.

Your “symmetrical circle tool” isn’t drawing circles from the same centre each time, nor is it centered on the rotation centre of the sky in either image.

While we’re discussing photos of the stars, have you made sure these images were made with a perfectly rectilinear lens, one that was distortion-free? It would help your case to know.

Equally, you couldn't prove that if you did find an image of circular star trails that it wasn't edited to fix distortion.

[Tom Bishop]

Here is an example to try, with some nice straight lines in the foreground.

https://www.reddit.com/r/BeAmazed/comments/50ziy3/long_exposure_of_star_trails_against_a_farmhouse/



Hold shift with the circle tool in paint.net for a symmetrical circle. The curves just aren't arcs of a circle, and nor are they concentric:

[JSS]

And as pointed out, you didn't draw your circles centered, so of course they are not going to line up.

The star trails are too short in your example. The point is to continue the curve, not center the circle.

My star trails are long enough to show they are circular and not veering off course or heavily distorted.  I'd take a better one tonight if I didn't have clouds.

If you don't center the circle at the point of rotation then of course the circles you draw are not going match. That's how circles work, if you move your circle off-center then of course your circle won't line up. It's impossible for two circles with different origins to line up.

The bigger problem is you can use any computer star-chart program to generate these circles, and see they are indeed circles. And you know those star tracking programs are right because you can take a telescope and point it where the chart says the star is and it's right there, every time.  You can even take pictures and line them up with screenshots.  If the stars were NOT going in concentric circles then nobody would be able to find them with a telescope.

Using random images from the internet without understanding what lens and camera were used is not going to give you reliable results.

[Tom Bishop]

There is a straight line reference in my previous image. Prove that it's distorted.

The image you provided has zero references to show that it is undistorted and unmodified, and is not following the procedure described.

[Iceman]

There is a straight line reference in my previous image.

How many images from balloon footage have you discredited despite having the exact same components?

[JSS]

There is a straight line reference in my previous image. Prove that it's distorted.

The image you provided has zero references to show that it is undistorted and unmodified, and is not following the procedure described.

Prove it's not distorted.

Neither of us can prove anything with that photo because we don't know the details of the camera that took that photo, nor the size and shape of the ground features shown or the exact position of the camera nor do we know what if any image processing was done after the photo was taken. With all those unknowns it's impossible to make any determination at all, which is why I said using random images from the internet is fruitless in trying to prove your case.  That's why I used one of my own, I know all these things.

The procedure as described? What exactly is this procedure and what is it's purpose?

I use a lens specifically designed for no distortion, I'm quite aware of it's capabilities. What 'references' do you require as proof? What could I possibly do to prove to you that the image isn't distorted or modified? Modified how?

You ignored my points about using astronomical star finding software to show that stars do indeed go in perfect circles, backed up by the fact I can use them to find any star in the sky and it's always accurate. Even screenshots can be lined up with actual photos, and I have done this many times to identify stars and features.

[Tom Bishop]

Prove it's not distorted.

Neither of us can prove anything with that photo because we don't know the details of the camera that took that photo

Actually, if there is a straight line reference in the photo, it will show whether the lens is producing distortion. Try again.

[Longtitube]

Tom, you haven’t made a convincing case. The star trail simulation isn’t convincing either; I have never seen the sun or moon rise or set at accelerated rates like in the simulation, nor does either sun or moon elongate as seen rising and setting in the simulation, so that won’t wash. Quoting a video on refraction showing refractive effects within a degree or so of the horizon doesn’t prove your case for the whole sky either.

The OP’s question is still unanswered, why do stars which supposedly circle above earth set?