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   Trammell Hudson (th@social.v.st)'s status on Monday, 28-Apr-2025 04:02:38 JST Trammell Hudson

   Is anyone manufacturing custom slide rules?

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     Trammell Hudson (th@social.v.st)'s status on Monday, 28-Apr-2025 04:02:27 JST Trammell Hudson

     in reply to

     That appears to correctly compute sin(declination)*sin(latitude) now

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     Trammell Hudson (th@social.v.st)'s status on Monday, 28-Apr-2025 04:02:28 JST Trammell Hudson

     in reply to

     Better, although now I'm worried that instead of computing the elevation of the sun, this slide rule will summon a demon instead

     ✧✦Catherine✦✧ repeated this.
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     Trammell Hudson (th@social.v.st)'s status on Monday, 28-Apr-2025 04:02:29 JST Trammell Hudson

     in reply to

     that's not quite right for the declination compensator.

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     Trammell Hudson (th@social.v.st)'s status on Monday, 28-Apr-2025 04:02:31 JST Trammell Hudson

     in reply to

     Paper prototyping reveals that the inner and outer rings of the circular slide rule should have a larger difference in their diameters.

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     Trammell Hudson (th@social.v.st)'s status on Monday, 28-Apr-2025 04:02:32 JST Trammell Hudson

     in reply to

     The slide rule's refraction adjustment is now temperature compensated.

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     Trammell Hudson (th@social.v.st)'s status on Monday, 28-Apr-2025 04:02:34 JST Trammell Hudson

     in reply to

     No, that is not actually useful as a slide rule.

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     Trammell Hudson (th@social.v.st)'s status on Monday, 28-Apr-2025 04:02:35 JST Trammell Hudson

     in reply to

     although this arrangement for the solar declination correction might be better, even though it makes low d changes less accurate.

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     Trammell Hudson (th@social.v.st)'s status on Monday, 28-Apr-2025 04:02:37 JST Trammell Hudson

     in reply to

     Now with solar declination and sine/cosine tables (in addition to height of eye correction, refraction, parallax, and upper/lower limb calendars)

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     Trammell Hudson (th@social.v.st)'s status on Wednesday, 07-May-2025 23:06:54 JST Trammell Hudson

     in reply to

     Printed and laminated a prototype of my solar slide rule on 350g A3 at the local print shop and it works fairly well! Correcting sextant height for index error, temperature, refraction, height of eye and lower limb is fast, as is computing latitude from the noon sight. Computing Hc and Z is a bit more involved (using additional scales on the reverse side)

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     Trammell Hudson (th@social.v.st)'s status on Wednesday, 07-May-2025 23:06:57 JST Trammell Hudson

     in reply to

     The combined Latitude, Declination, LHA grid didn't work, so instead I've added the normal S/ST, and T/T1/T2 scales to allow computation of Hc and Z from the corrected sextant height.

     ✧✦Catherine✦✧ repeated this.
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     Trammell Hudson (th@social.v.st)'s status on Wednesday, 07-May-2025 23:07:01 JST Trammell Hudson

     in reply to

     Following up on the original question... Concise Products in Japan seems to still be producing circular slide rules https://www.sliderule.tokyo/products/detail.php?product_id=7