150 Pages Later: The Skyward 200 Assembly Manual

I didn't think writing a manual for the Skyward 200 would take very long. It turned into a full time job for a month, and it still isn't quite finished. The result is the Skyward 200 Visual Assembly Manual, about 150 pages, and it is in final edits right now.

Why a Manual?

Until now, if you wanted to build a Skyward, you had the files on GitHub and our build videos on YouTube. That works for a lot of people, but the Skyward 200 is a substantial project, and I wanted a way for people to plan it.

Here is the kind of situation I had in mind. Say a high school class is building a Skyward 200. One student has the project manager or materials manager role, and another student is doing the assembly. Before the next session, the project manager wants to know exactly what the assembler will need for the next part of the build: which parts and which tools.

So the manual is broken into sections: the rocker box, the tripod, the focuser, the optical tube and the solar filter, with 106 numbered steps between them. Each section starts with a list of every part it needs. The rocker box and tripod section alone uses 108 pieces. Then every step lists its own parts and tools right at the top, so a build can be organized ahead of time instead of figured out on the spot.

Slowing Down

Writing it also gave me a chance to slow down. There are bits of advice, safety tips and small details that I might speed through in a video, and now they are spelled out. The very first page after the cover is about the Sun, and how to keep a telescope from blinding you or setting something on fire. The Skyward 200 is only safe for looking at the Sun with the solar filter from the manual in place. Before any assembly starts there are pages on tools and tool safety, and a reference for every kind of screw, nut and insert you will meet.

Some things matter before you ever start printing. These telescopes have large parts, and different filaments, printers and slicer settings shrink differently as they cool. On a large part that can add up. So shrinkage calibration comes early in the manual: print a test file, measure it, scale your slicer to match, and check the fit before committing to the whole set of parts.

Taking a Telescope Apart, Digitally

I made the manual in Fusion 360, the same CAD software I used to design the telescope. To show each step, I had to take the whole telescope apart in the software, then put it back together one step at a time, highlighting the parts that go on in each step.

In some ways that was slower than designing the parts in the first place. I have newfound respect for people that do documentation for a living.

An Educators Version

There is one more piece I want to add before I call it done: an educators version.

A Skyward 200 is full of practical physics, and students who build one have applied a lot of it without necessarily noticing. Take friction. There are two kinds: static friction, which holds two surfaces together until something pushes hard enough to start them moving, and kinetic (or dynamic) friction, which resists them once they are sliding. The telescope uses both, in two opposite ways.

In the Crayford focuser, a turning shaft drives the drawtube using nothing but friction where the two touch. Here we want static friction to win every time. If that contact ever starts to slide, the focuser slips and you lose your focus. The goal is for the contact to stay static and never become dynamic.

In the altitude and azimuth bearings it is the other way around. The telescope rides on Teflon pads against ABS or ASA, which were chosen partly for how they slide together. Here we want the force it takes to get the telescope moving (overcoming static friction) to be closely matched to the force it takes to keep it moving (kinetic friction). If static friction is much higher, the telescope sticks, then lurches past your target when it lets go. When the two are closely matched, it moves with a smooth, buttery feel and stays put when you let go.

Same physics, two opposite design goals.

The educators version will point out connections like that, so the teacher overseeing the build can help students have those revelations about what they have built.

How to Get It

The full manual is coming soon, and it will be free, on GitHub and here on tentelescopes.com. The goal is to give everyone the best chance of success with their build.

The educators version will be locked and only available to educators registered with Ten Telescopes. If you are an educator, email me at admin@tentelescopes.com to register.

Stay tuned for the release!

Questions about building a Skyward? Ask on our Discord.