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So let's have a look at the first results

A project log for Effect of moon phase on tombstoning

I'll assemble a PCB with a couple of very small components every week and track the effect of moon phase on tombstoning.

ChristophChristoph 06/20/2022 at 22:210 Comments

So far I've only assembled some boards and noted problems that occured. Let's give all that some context.

First of all, in order to see what effect the moon phase has (note: I'm not phrasing this as an "if"!), we need to calculate the phase, at least roughly. At this stage I don't it matters much if we're slightly off.

One lunation (see here: https://en.wikipedia.org/wiki/Lunar_month) takes 29.530589 days on average, and we can calculate the number of lunations since january 1st, 1923 (full moon, roughly) for a given day by dividing the days that have passed since then by those 29.5xxxxx days. Great. The remainder is the number of days within the current lunation. We can use that to calculate the phase (as a fraction), again by dividing by 29.5xxxxx days.

For a first overview, I created a plot for all assembled boards. Each point in the following plot represents an assembled board. The lunation starts at x=1, y=0 (full moon) and evolves counter-clockwise. Waning moon is in the top half (x=0, y=1 would be half moon) and waxing moon in in the bottom half, new moon is to the left (x=-1, y=0).

There are some obvious gaps but they'll hopefully vanish over time. These were all boards, so what about those with problems? Here we go:

Lo and behold, that's a pattern. But let's not jump to conclusions about the reasons now. I still have tons of resistors here!

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