Long focus singlet lenses-Surplus Shed

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Merlin66
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Long focus singlet lenses-Surplus Shed

Post by Merlin66 »

Surplus Shed have a special running at the moment on long focus lenses- 2500 to 4000+mm with apertures of 150mm.
These sound ideal for anyone considering building a spectrohelioscope.


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Re: Long focus singlet lenses-Surplus Shed

Post by highfnum »

you will need to stop down aperture
quality across surface not that good
I have 150mm by 4000

cut to 100mm then its ok

I wound up grinding a few of my own
hence "highfnum" I have 24 and 48 feet 125mm lens


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Re: Long focus singlet lenses-Surplus Shed

Post by highfnum »

here is test I did
6 inch SS lens cut to 4 inch
sun dia is about .75 inch I counted 8.5 feet from lens to wall
surplustestsm.jpg
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Re: Long focus singlet lenses-Surplus Shed

Post by highfnum »

I ground my own 24 feet FL lens (5 inch 120mm)
it creates image over 2 inches
24lenssm.jpg
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24sunsizesm.jpg
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Re: Long focus singlet lenses-Surplus Shed

Post by marktownley »

Impressive John!


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Re: Long focus singlet lenses-Surplus Shed

Post by highfnum »

thx mark

i sold a couple of these one to someone in France
one to Canada

i plan to write article on how i make them

it takes about 35 to 40 hrs


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Re: Long focus singlet lenses-Surplus Shed

Post by marktownley »

Please share the article here too thanks John


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