Random Jottings

The Missing Manual has gone missing! As some of you might have noticed, the Joomla site for Astrolabe: The Missing Manual is gone. Like the original wiki it replaced, it was not meeting my needs, so I nuked it.  Do not despair! The manual still exists, and is still being added to regularly (more regularly […]

Drafting the Astrolabe 10: The Shadow Squares – Completed

I thought I posted this two weeks ago… Work and life have gotten busier than I realized it seems. Anyway, here is the completed shadow square section. Next up will be the unequal hours scale and then the back will be done.

Drafting the Astrolabe 10: The Shadow Squares

Getting the zodiac and calendar rings done was probably the worse, most finicky part of this project; the rest of the tasks remaining might require careful measurement, and attention to detail, but orders of magnitude less work than the last section. The next task is to finish off the rear of the astrolabe. Two scales […]

Drafting the Astrolabe: Concerning Accuracy

In working with a compass and a straight-edge I’m finding that there are techniques that can be used to improve the accuracy of the drawing. When drawing arcs to bisect lines or angles it is best to set the compass radius so that the construction arcs cross as close to 90 degrees as possible. The […]

Drafting the Astrolabe 9: The Calendar Ring

Well… That was a bit more intense than I expected. I was expecting that drawing the calendar ring on the back of my astrolabe would be rather involved, but actually doing it took more patience than I expected. This was definitely the hardest part so far. Drawing the offset ring was straight-forward. As described previously computing the […]

Drafting the Astrolabe 8: On Tools

While I’m working on this project, I’m also researching the tools and techniques used by the instrument makers who made these astrolabes. The two period manuals I am working from assume a certain shared level of knowledge, and do not mention tools or engraving techniques, except in passing. I am finding the art of the […]

The Future: Moving the Astrolabe Generator away from Flex

I like Flex, but the tools to use it are not cheap. I can’t afford $250+ for the next version of Flash Builder and from what I’m seeing even Adobe is jumping on the HTML5 bandwagon. If Adobe offered a free, noncommercial version of Flash Builder, I might be convinced to stay with the platform. […]

The Future: Version 3 of the Astrolabe Generator

I spent most of the last weekend coding like crazy. I now have three new optional scales to add to the back of the astrolabe: The Lunar Mansions. A calendar/astrology scale. This is visible inside the shadow squares, center bottom. Two views of the Arcs of the signs: Equal sized and projected(top left shows the […]

Drafting the Astrolabe 7: The Calendar Scale.

The next step in drafting the astrolabe is constructing the calendar scale. Up until now the process of creating scales has been straightforward. The time scale on the front and the altitude and zodiac scales on the back are simple in concept and execution, requiring no math to draw. The calendar scale, on the other […]

Drafting the Astrolabe 6: The Zodiac Scale

OK, yes, that was tedious. But now it is done. I have started work on the back of the astrolabe: The first scale, the zodiac ring, is finished. Drawing this used a combination of geometric construction and fudging with the compass. First, draw the outside edge of the astrolabe (set the compass using the finished […]