The SkyPacer is designed to help with BSA First Class requirement 4a about measuring the height of a tree, tower, etc.

Creality

Ender 5

Doesn't Matter

No

layers 0.2mm, lines 0.4mm

20%, lines, gave a good rigid structure

Print with NO SUPPORTS, otherwise the vitally important sighting holes will be filled by supports and the SkyPacer will be unusable.

The SkyPacer has two round through-holes offset by 45 degrees in angle. When you can see the base of a tall object through one hole and the top through the other, your eye is at one vertex of a 45-45-90 right triangle. The legs are equal, so your distance from the base of the object equals its height. (See sketch.)

Let's say you are trying to measure a tower.

1. Stand well back from the tower.

2. Hold the SkyPacer vertically (curving toward you) so that you can see cleanly through both holes (with one eye) by moving only your eye. 3 or 4 inches from your eye is about right.

3. Position the SkyPacer to center the base of the tower in the lower hole.

4. Holding the SkyPacer still and moving only your eye, check what you see through the upper hole:

4a. If you see part of the tower, not the top, you need to move some distance farther from the tower and repeat from step 2. WARNING: Don't walk backwards -- turn around and look where you're going!!!!!

4b. If you see the sky above the tower, not the top, you need to move some distance closer to the tower and repeat from step 2. Watch where you're walking!

4c. If you see the top of the tower, centered: Congratulations -- you are standing at the vertex! From the vertex (where you are standing) to the base of the tower is equal to the height of the tower. Walk toward the tower using your practiced measured pace, counting off the steps or distance as you would do on a leg of an orienteering course. The distance from your start point to the tower is a good estimate for the height of the tower.

Technically, rather than sighting the lower hole on the base of the tower, you should center it at your eye level on the tower, so that the horizontal-ish leg of the triangle is truly horizontal. Then, after pacing the distance back to the tower, add the height of your eye above the ground to get the final estimate.