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Herritage 130p anomaly


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Good Afternoon to you all.

If i get it right then my 130p is a newtonian which is inverting image upside down and left to right. But then ehm....... why when i look with it on some terrestrial object i can see it normaly? Today i look at house at the end of our street and it was perfectly normal. ????? what the...???:rolleyes::eek::)

Any explanation?

Thanks a lot

:eek:

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A reflector shows the image upside down and a refractor show the image upside down and also left to right.

You say your scope shows correct images, in that case all I can think of is you have an erecting prism fitted which turns the normal upside down image upside down again thus making a correct image.

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:D no i havent. all i used was my 25mm eyepiece fitted.......

now when im thinking about it i can remember that i was looking into it from the right side of the scope..... normaly i would be standing from the left side. So afterall its my own stupidity :headbang:

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maybe I'm being really thick but how can you look at it from the "right side" when the e/p is on the left side:icon_scratch:. reasoon i ask is that I bought a teeny (76mm) dob for my kids and it says on the box something along the lines of if you look from the front or something that the image will not be inverted. Does that make sense? :headbang:

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Does that make sense? :headbang:

Yes.

Say a tree is viewed. The light from the top of the tree comes out the bottom of the eyepiece, when a normal viewing position is used

If you look from the front, what is normally the bottom of eyepiece ( i.e., the image of the top of the tree) will now be the top, what is normally the left of eyepiece will now be the right, etc.

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Yes.

Say a tree is viewed. The light from the top of the tree comes out the bottom of the eyepiece, when a normal viewing position is used

If you look from the front, what is normally the bottom of eyepiece ( i.e., the image of the top of the tree) will now be the top, what is normally the left of eyepiece will now be the right, etc.

but how do you look from the front? wouldn't your head be in the way of the light hitting the mirror?

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To be honest I'm having a lot of trouble to understand how turning a scope the wrong way around, would correct the upside down effect!

I mean, the primary is spherical (or elliptical), so turning it around won't change the "shape" of the mirror in relation to the light bouncing on it. The light cone generated should still converge at a spot and "expand" again to an inverted cone, thus inverting the image in bout vertical and horizontal dimensions.

If anyone can share a light on this please do. I like understanding stuff and this is making everything confusing! :headbang:

EDIT: I want to add, if it did correct the image why wouldn't the manufacturers just rotate the mirror 180º inside the tube and make our lives easier? The way I see it, if you cut an ellipse or a circle in half, the half's should be copies of each other and behave the same way, so a 180º rotation wouldn't have any meaning.

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EP is on the left side of the tube when looking from behind the tube towards the target. Rotate the tube so the EP is on the right. Go stand on the right and look through it. The top of the EP is now at the bottom. So image is corrected. That's my understanding of what George said above. But I have never tried it so I could be wrong :headbang:

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Maybe that's it. 1st thing I'll do when I get home is to twist the OTA in anyway imaginary to figure out how it works! :headbang:

I hope my wife doesn't put me in some mental institution when she sees me going crazy on the thing! :D

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I apologize for my obtuse explanation. This is something that, for me, is difficult to explain using written words, but that would be easy to demonstrate if we all were gathered around a scope. I'll try again.

Take a Dob out in the day and look at a tree that is at a distance such that it just fills the field of view. If the land is level and the tree is sufficiently distant, the scope will be horizontal. Assume that the scope is rotated such that the eyepiece is straight up-and-down. Stand (or kneel) behind the scope, bend over, and look in the eyepiece. The tree's image is inverted.

Now, without moving the scope, move to a position halfway between the front end of the scope and the eyepiece. Turn round, so that you're now facing the eyepiece with your body almost against the scope's body (still halfway from the end). Bend over and look through the eyepiece. The actual tree will now be behind you, but the image in eyepiece will be of a tree with normal orientation.

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I apologize for my obtuse explanation. This is something that, for me, is difficult to explain using written words, but that would be easy to demonstrate if we all were gathered around a scope. I'll try again.

Take a Dob out in the day and look at a tree that is at a distance such that it just fills the field of view. If the land is level and the tree is sufficiently distant, the scope will be horizontal. Assume that the scope is rotated such that the eyepiece is straight up-and-down. Stand (or kneel) behind the scope, bend over, and look in the eyepiece. The tree's image is inverted.

Now, without moving the scope, move to a position halfway between the front end of the scope and the eyepiece. Turn round, so that you're now facing the eyepiece with your body almost against the scope's body (still halfway from the end). Bend over and look through the eyepiece. The actual tree will now be behind you, but the image in eyepiece will be of a tree with normal orientation.

Thanks, that makes perfect sense now! The upside down will be corrected that way. It will still be fliped horizontally, right?

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It will still be fliped horizontally, right?

Suppose that there is a kite stuck in the (actual) right side of the tree. When you use the scope from the normal position behind the scope, the image is inverted both horizontally and vertically, and the kite appears on the left of the image. Suppose further that your that your left shoulder points to actual west in the normal position. When you use the scope from the "new" position, you're now facing "backwards", and your right shoulder points to actual west, so you see the kite on the right side of the image of the tree.

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Suppose that there is a kite stuck in the (actual) right side of the tree. When you use the scope from the normal position behind the scope, the image is inverted both horizontally and vertically, and the kite appears on the left of the image. Suppose further that your that your left shoulder points to actual west in the normal position. When you use the scope from the "new" position, you're now facing "backwards", and your right shoulder points to actual west, so you see the kite on the right side of the image of the tree.

Yeah you are right.

I was trying to mimic this with a paper printed on one side. The 1st time I rotated vertically and then flipped horizontally, while the light cone doesn't rotate the image, it flips it twice, one vertically and one horizontally.

Flipping the paper twice and then moving the observer (me) 180º around corrects everything.

Thanks for your patience! :headbang:

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Whoa :D . Im sorry guys i didnt want to create such confusion :headbang: . I was simply leaning over the telescope because i had to. there was no access from the other side. Anyway im glad that this mystery is sorted :D:D:D.

What a awful day in work i had. Now praying for clear skies tomorrow night.

GN

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Whoa :D . Im sorry guys i didnt want to create such confusion :headbang: . I was simply leaning over the telescope because i had to. there was no access from the other side. Anyway im glad that this mystery is sorted :D:D:D.

What a awful day in work i had. Now praying for clear skies tomorrow night.

GN

I'm glad you did. Gave me the chance to learn more about how optics work. :)

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