Building a Brass Astrolabe

I made my own brass astrolabe to keep me busy during the pandemic. No 3D printers, or digital shapers were used in the construction; and no animals were endangered either before or after the construction.

[@Chiefskingdom58]

Thanks for sharing, amazing workmanship

[@electrictao5180]

Nice work. Thanks.

[@gagatube]

Very nice work Mr Hartley. That instrument must represent a considerable number of man-hours of work. Thank you for your explanation of engraving, which I previously knew nothing about! My main question is how did you know where to engrave the arcs? Particularly for the Almucantars and the Azimuths, which do not look at all easy (at least to my eyes). Also please point out to your viewers that when you are using the Alidade (the sighting part on the back) to measure the altitude of the Sun, you *don't* look through the sights at the Sun, instead you stand with the sun behind you, holding the Astrolabe vertically, in the sunlight, and align it with the sun by looking at its shadow. Then adjust the Alidade until the bright spot from the first sight illuminates the hole in the second sight.
The Astrolabe is an amazing instrument, capable of a lot more than telling the date and time. In the 10th century an Arabian scholar called Al-Sufi published a book listing over 1000 uses for Astrolabes. They were even used for determining a person's birth horoscope, in the days when Astrology was regarded as a practical science.

[@charleshartley440]

Thanks for the kind words. I had not know of Al-Sufi. Chaucer, a few centuries later, also wrote "A Treatise on the Astrolabe" listing a 1000 uses; probably copied from Al-Sufi.
For the markings I researched the geometry and mathematics, and wrote a Python computer program to draw the figures for the markings for my latitude; I then transferred the markings to the brass for the engraving. The math is mostly trigonometry and a little spherical geometry.
If I could figure out how to post a photo in this comment section I would show the photo of what the program produced.
The sighting holes on my astrolabe are so small that they cut down the light considerably. I can sight the Sun easily with out fear of eye damage. I made a octant (separate CZcams video); it needs a filter protect the eye.
czcams.com/video/UQli6PriALo/video.html

[@evanboxer-cook2034]

Impressive!