Design Constraints

The maximum height in my trunk is a bit less than 12". This was the most critical design restriction in the whole process. As a result, a lot of creative thinking was done on how to cope with that problem. This lead to some very "outside the box" thinking.

One idea to get more height was to removed my spare tire. I really don't want to get a flat late at night out on the rugged terrain of a remote observing site without my spare though. So removing the spare was not considered for very long. Another clever idea that wasn't considered for very long was to replace the lid of the trunk with something that would give the trunk more depth. If I were going to drive an ugly car though, I would have never bought the Miata to begin with.

Originally the plan was to nest all the pieces of the scope inside the rocker box. The secondary cage, and in particular the height of the secondary mirror holder made this impossible though. Putting the secondary cage along side the rocker box in the trunk meant that the trunk's hinges for were a factor and those hinges are well below the 12" height of the rest of the trunk.

It turns out that back wall of the trunk slopes forward as it goes up towards the roof at about a 45-degree angle. This meant that by making the rocker box shorter to clear the hinges, I could make the rocker box wider too - just barely wide enough in fact to accommodate a 15" mirror.

In order to make the mirror box that short though, the side bearings had to come off. The good news here is that they can lay on top of the secondary cage and the box with the rest of the scope. They are small enough to clear the hinges and are narrow enough so that the angled back wall of the trunk isn't an issue.

Before finalizing my plans, I made some wooden boxes of the size and shape I expected the secondary cage and rocker box to be. I used them to successfully test the following three things:

  1. The trunk closes.
  2. When the hinges swing down, they don't scrape the top of the scope
  3. I could get both the boxes (as a pair) into and out of the trunk. This was an issue since parts of the secondary cage and rocker box would need to fit under the top lip on either side of the trunk. It would be heart breaking to build something where each piece fits where it belongs, but where one piece can't be placed in the trunk when the other is already in there.

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Last updated 8/6/05