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  • Wide Angle Reflex Finder for Amateur Astronomers

    Sorry, but it looks like the L11832 is no longer available. (The C11832 must be a typo.)I would suggest using a smaller diameter lens, maybe one of the 38 mm ones, with a focal length close to 125 mm. Surplus Shed has the L1632 (38 mm diameter, 125 mm focal length) but it does not have an anti-reflection coating. No coating could cause a ghost image of the reticle, but might be worth a try. L14304 has a diameter of 34.7 mm and a 125 mm focal length and comes with an AR coating. You would have to wrap some tape around the edge of the lens to increase its diameter to fit into the 3D printed lens cell. Should be easy to do.I may have to redesign the WARF to accommodate a wider range of lens focal lengths. This may not be easy. I have no estimate about when I might get back to this pr…

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    Sorry, but it looks like the L11832 is no longer available. (The C11832 must be a typo.)I would suggest using a smaller diameter lens, maybe one of the 38 mm ones, with a focal length close to 125 mm. Surplus Shed has the L1632 (38 mm diameter, 125 mm focal length) but it does not have an anti-reflection coating. No coating could cause a ghost image of the reticle, but might be worth a try. L14304 has a diameter of 34.7 mm and a 125 mm focal length and comes with an AR coating. You would have to wrap some tape around the edge of the lens to increase its diameter to fit into the 3D printed lens cell. Should be easy to do.I may have to redesign the WARF to accommodate a wider range of lens focal lengths. This may not be easy. I have no estimate about when I might get back to this project at this time. Good luck!Bob

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  • Jack,Hi. You should usethe part number L11832 from Surplus Shed. It is a 40 mm diameter achromatic lens with a 125 mm focal length. The housing and lens holder included in the design arespecific for this lens. You cannotsubstitute without impacting the housing design provided in the design. You would have to redesign for a different focal length.I do not know if the recommended achromatic lens has an asphericsurface or not. My guess is that all surfaces are spherical. Frankly, it doesn’tmatter. It is a well corrected 40 mmdiameter collimator, and works for the intended purpose. Since it is being used with a red LED (singlewavelength), it doesn’t really need to be an achromat. An aspheric lens would be be way overkill andexpensive. Good luck, and reply with any comments or further …

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    Jack,Hi. You should usethe part number L11832 from Surplus Shed. It is a 40 mm diameter achromatic lens with a 125 mm focal length. The housing and lens holder included in the design arespecific for this lens. You cannotsubstitute without impacting the housing design provided in the design. You would have to redesign for a different focal length.I do not know if the recommended achromatic lens has an asphericsurface or not. My guess is that all surfaces are spherical. Frankly, it doesn’tmatter. It is a well corrected 40 mmdiameter collimator, and works for the intended purpose. Since it is being used with a red LED (singlewavelength), it doesn’t really need to be an achromat. An aspheric lens would be be way overkill andexpensive. Good luck, and reply with any comments or further questions.Bob

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  • Hi Gravitino,I have modified the chassis to interface with a standard Telrad base. I printed it out and it seems to work fine. Thanks for the suggestion.

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    • Wide Angle Reflex Finder for Amateur Astronomers
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