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.
Long focus singlet lenses-Surplus Shed
- Merlin66
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Long focus singlet lenses-Surplus Shed
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
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"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: Long focus singlet lenses-Surplus Shed
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
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
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
6 inch SS lens cut to 4 inch
sun dia is about .75 inch I counted 8.5 feet from lens to wall
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Re: Long focus singlet lenses-Surplus Shed
I ground my own 24 feet FL lens (5 inch 120mm)
it creates image over 2 inches
it creates image over 2 inches
- marktownley
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Re: Long focus singlet lenses-Surplus Shed
Impressive John!
http://brierleyhillsolar.blogspot.co.uk/
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Re: Long focus singlet lenses-Surplus Shed
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
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
- marktownley
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Re: Long focus singlet lenses-Surplus Shed
Please share the article here too thanks John
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!