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 […]
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 […]
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 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 […]
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 […]
The next big chore will be creating the major scales for the back of the astrolabe. This will involve drawing one set of rings representing the Zodiac and another set representing the Calendar. Drafting the zodiac is straight-forward, if tedious. The circle needs to divided into 360 one-degree ticks. The process is the same one […]
Back to work on this project: I got several tasks done today. When I am finished drafting my astrolabe, I plan on photocopying it onto card stock, and assembling and laminating it in order to compare it’s accuracy to a computer-generated version. I tested the photocopy process today. First, I printed out the front of […]
I have just uploaded the last tweak I’m planning on making to version 2 of the Astrolabe Generator. I’ve done a lot of work on it over the last few weeks, and I’m happy with the results. I will still be planning to add more scales and functionality in the future, but it is time […]
After Stoeffler This does seem a bit extreme, but the purpose of this project is to see what can be done with just a straightedge and compass. Building my own protractor serves two purposes. One: It proves to me that an accurate tool can be made this way. Two: It gives me a chance to […]
Hartmann’s Practika is a collection of writings by the 16th century instrument maker Georg Hartmann. These detail the steps to design a range of sundials, and extensive notes on astrolabe construction. Hartmann begins by demonstrating the geometrical construction techniques he will be using. Given how complex some of the design work will be, this seems […]