Notices by Trammell Hudson (th@social.v.st)

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

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.

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)

Using a nuke to take down a blimp seems like overkill, but it's the only way to be sure.

Meanwhile in Amsterdam

Moore's Law illustrated. #HPC

But FORTRAN is forever. #HPC

@quixoticgeek not everything is so evenly divided.

Is anyone manufacturing custom slide rules?

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

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

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

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

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

that's not quite right for the declination compensator.

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

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

Good morning Sint Maartin! All the squares and stay sails are neatly harbor furled and we are at anchor awaiting customs clearance.

The photo heatmap reveals our route from Cape Town to Saint Helena to Sint Maarten sailing on the trade winds for 6176 nautical miles. This is where I'm stepping off the ship, which will continue its world tour and return to Amsterdam for SAIL2025. Thanks for following along on our voyage crossing the South Atlantic and maybe see you next year for another trip!

Last sunset at sea. Around midnight we will douse and stow all of the sails and need to motor the last mile into the anchorage since the winds are directly against us.