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Seeing the right way round in a reflector?


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Hello All.

Firstly I would like to say I am getting rather annoyed at the cloudy nights recently! :-)

I think I am going to answer my own question here but here goes. I have a 130p Spywatcher Reflector scope. Also recently upgraded some of my eyepieces to Meade 4000 series. Thing is over the last 10 months of getting used to using my scope I still have trouble navigating due to the upside down wrong way round view I get through looking through the eyepiece. No matter how many times I use it I end up going up instead of down etc....

So I was thinking is there a way to correct this?

Then I found this on FLO First Light Optics - William Optics 1.25" 45 degree Erecting Prism

So presuming this 45 deg prism corrects the image for me to see it the right way up.

Are they worth buying? is there pro's and cons to using them.

My basic logic suggests that using the prism I may loose some of the clarity of the image?

I hope you guys understand and maybe be able to advise.

thanks

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In principle, any extra "thing" in the light path will affect the image, so it's probably better just to get used to things being upside down. I too used to find it quite confusing, but I found that I could get a better feel for controlling the scope by thinking about moving the object around in the eyepiece, rather than moving the scope, if that makes sense.

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Thanks for the quick response. I understand what your saying and it was kind of what I thought. Reassures me all the same.

My problem is finding objects. I know where some things are now like Andromeda and great cluster in Hercules, M3 cluster etc. So finding them is easier. New faint fuzzes can be very tricky. I was out looking for the whirlpool galaxy and could not find it at all and spend about an hour trying, getting my left and rights confused all the time... Maybe that abject I am unable to see in my garden with light pollution etc. It just seemed an easy one to find using Stellarium and Turn left at orion (or is it turn right...!!! in my case)

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I can understand where you are coming from but the inverted image is standard for newtonians so we have all had to get used to that. The inverting prism won't work with a newtonian as there is not enough focus travel - you would not be able to bring anything to focus with it in the drawtube.

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although some people really like them, I find equatorial mounts annoying for visual use.

with some mounts it may be possible to set it at 90 degrees and use it in alt azimumth mode but not sure about the mount you have.

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Seeing an upside down, inverted (back to front) image through the eyepiece isn't the problem. In my view (sorry no pun intended) using the right type of finders will be the solution. First the Telrad, which works by keeping one eye on the sky whilst the other one looks through the clear screen of the Telrad (which has an illuminated red circle projected upon it) so that a red circle magically now appears imprinted on the night sky itself. You then point this circle (your scope) to the same part of the sky that is shown in your star map. Second, moving to a 'right angled' finder, you can then use this to direct your scope closer to the target because you can see more detail through this magnifying optical finder. Now the image in this type of finder is the right way up but still remains back to front but at least getting your head round only one orientation makes life a little simpler and remember, you are almost on your object from using the Telrad. Only then do you look through your eyepiece, though the orientation of the final image is not important because there is no true orientation in the universe.

The Telrad does rely on you being able to see star formations as you hop across the sky. In light polluted areas this of course is made a little bit more difficult hence the need to rely on an optical finder as well to help magnify faint stars. If you purchased a right angles finder that allowed a diagonal, in theory you could use a prism to provide a 'correctly' orientated image but you are looking at a bit of kit that is not cheap.

Hope that helps.

James

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I can understand where you are coming from but the inverted image is standard for newtonians so we have all had to get used to that....

After 30yrs observing, i still can't get on with an upside down moon.

Back to front, no problem.

I guess most people adapt eventually though....or buy a refractor. :)

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it's funny you should say that as I prefer an upside down moon to a right left reversed moon. at least with the former you can turn the map upside down and it's correct. each to their own in the excellent pursuit.

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After 30yrs observing, i still can't get on with an upside down moon.

Back to front, no problem.

I guess most people adapt eventually though....or buy a refractor. :D

I have 2 refractors and 2 newtonians and sometimes have one of each design on the mount at the same time - switching between the two can sometimes be disconcerting though, I agree :)

As Kai says, who's to say what is "up" and "down" in space though ;)

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I can understand where you are coming from but the inverted image is standard for newtonians so we have all had to get used to that. The inverting prism won't work with a newtonian as there is not enough focus travel - you would not be able to bring anything to focus with it in the drawtube.

Big thanks to you sir! knowing I can't focus has just saved me money! cheers

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The Telrad does rely on you being able to see star formations as you hop across the sky. In light polluted areas this of course is made a little bit more difficult hence the need to rely on an optical finder as well to help magnify faint stars. If you purchased a right angles finder that allowed a diagonal, in theory you could use a prism to provide a 'correctly' orientated image but you are looking at a bit of kit that is not cheap.

Hope that helps.

James

Thanks James, I did look into the telrad system some months back but actually decided on changing my red dot finder to a finderscope. I was advised on this forum about the optical finder with a right angle was a good way to go.

I think perhaps I need to re-look into that possibility. The red dot finder is all very well when you know what to point at. However using my binos to see stars for reference then trying to point the red dot to a star I can not see without the binos becomes very challenging.

I think a good finderscope will be the answer for my problem as I am currently using the scope to "find" objects as the red dot finder is not accurate it just points me in a general direction. Whereas a good finder will narrow down the search area somewhat.

Thanks

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I forgot to say of course that the finder is only as good as its alignment to your scope. I would recommend keeping a key eye on the For Sale section here as Telrads (which you can dim!) and right angled finder scopes do come up quite frequently. Could always put a request in the wanted section too.

Hope you find something soon and keep us posted on what you're finding in the sky.

James

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