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Ok, this might be a crazy idea but I've been doing some research about interferometry where more than 1 telescope is joined together like the VLT in Chile, I was thinking, I have 2 small 76mm telescope mirrors and was wondering if I could build a telescope using them both. I would like to know if this idea below would work. Thanks

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I think the problem you will have is that the distances linking the scopes have to be precise within a fraction of a wavelength of light (i.e. several nanometers) in order that the images from the two scopes line-up precisely and don't cancel each other out.

You could try making your two mirrors into individual scopes that could be used as a pair of binoculars, but it would probably be easier/cheaper to buy a pair of 12x80s or 20x80s ...

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5 hours ago, Demonperformer said:

I think the problem you will have is that the distances linking the scopes have to be precise within a fraction of a wavelength of light (i.e. several nanometers) in order that the images from the two scopes line-up precisely and don't cancel each other out.

You could try making your two mirrors into individual scopes that could be used as a pair of binoculars, but it would probably be easier/cheaper to buy a pair of 12x80s or 20x80s ...

That's true what you said about precision, I wanted to use both of the mirrors together for astrophotography, I was thinking of using a laser to align the mirrors together 

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I think you will find that, whilst it is (relatively) simple to produce a single mirror to the required precision, building the mechanical bits to an accuracy of say 0.2 microns is a different matter. I believe the VLT runs the light down tunnels with mirrors on tracks that are computer controlled to ensure the distances are always right to align the light output to the precision required. I think it is all based on making sure the time taken for the light from each scope to arrive at the focus point is exactly the same - moving a mirror a few inches to increase/decrease the time by a tiny fraction of a second is easier than building a mechanical structure to the nearest nm or two.

As a proportion of the cost of the VLT, the system is probably worth it, especially as this enables scopes to operate "as one" with an effective diameter of the distance between them for the purposes of resolution - much more cost effective than a 30m diameter scope! But I don't think that would scale down effectively.

I admire the ingenuity and the way you are thinking "outside the box". But, for actually imaging something, I think the sad fact is that getting a single 110mm mirror (and keeping your 76mm mirrors in a box) would produce better results, be way easier to work with and it would probably cost a lot less as well.

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Even if you could align it in one orientation as you moved it it would shift by more than the required tolerance without active support.  I think it would be both complex and expensive to do this. Even pro observatories struggle to do optical interfertometry 

Regards Andrew 

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As already said, far too complex for amateur success. Best combined use would be a binocular telescope, the brain manages to process the two images to a single one with little problem and free!. A remarkable organ.    ?

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I would just get a 6" mirror (152mm) and avoid all the issues described above.  It would be a lot cheaper than recreating the precision of the VLT.  Even ganged together, you're looking at 107mm of effective aperture at best from a light gathering perspective.  If you can separate them over a great distance and recombine the images to the required precision; then yes, you would have enhanced resolution due to the long baseline.

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44 minutes ago, Louis D said:

I would just get a 6" mirror (152mm) and avoid all the issues described above.  It would be a lot cheaper than recreating the precision of the VLT.  Even ganged together, you're looking at 107mm of effective aperture at best from a light gathering perspective.  If you can separate them over a great distance and recombine the images to the required precision; then yes, you would have enhanced resolution due to the long baseline.

In one spatial direction only.

Regards Andrew 

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3 hours ago, Peter Drew said:

As already said, far too complex for amateur success. Best combined use would be a binocular telescope, the brain manages to process the two images to a single one with little problem and free!. A remarkable organ.    ?

This is your forte. Large Binocular Telescopes.

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A p[air of 76mm aperture bins would give immersive views of the moon etc.

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Posted (edited)

With standard parabolic mirrors I think you might end up with a nasty degree of spherical aberration as this set up would be working way off axis. Nice to see some original thinking going on. Keep the grey matter ticking.

Edited by Unklewhale

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Hi Arran

Many very well respected forum members have given you the down-low on your idea, and I believe you can safely rely on their judgement. 

 

However, if you want to give it a go, I say, give it a go! Do it because you’ll enjoy the project, and because it’ll be fun to play around with telescope bits, and because you’ll learn a heck of a lot doing it.... but just don’t hold too much prospect of it working.

 

You might want to take a look through the DIY astronomy section to see what others have got up to. Perhaps take some pictures of your project as you go and maybe start your own thread?!

 

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