What’s A Nonius? | Hackaday
If you already know what a nonius is, you possibly can in all probability skip this submit. But, if like us, you would need to look it up, we’ll let you know what we came upon. It seems, a translation mistake taught us a brand new phrase and a few historical past we weren’t conscious of.
Have a take a look at the adjoining graphic from a waveform show. What would you name the vertical crimson traces at positions 139 and 200?
We’d in all probability name them markers. Or perhaps cursors. The handbook, nevertheless, calls every one a “nonius”. It refers to them that approach a number of instances.
Oddly, the handbook additionally has sentences like “Select one nonius and right-click, after which choose ‘Remove Marker’ within the subsequent window to delete the nonius.”
So, clearly, a nonius is the vertical line marker or cursor. But that, after all, begs a query…
What is a Nonius?
Have you ever heard of the vernier scale? If you’ve executed navigation, used a standard caliper, or tuned an previous shortwave receiver, you in all probability have. [Pierre Vernier] developed it in 1631 as a approach to higher interpolate values on a scale.
However, there was an earlier model used to enhance measurements on astrolabes. A Portuguese navigator named [Pedro Nunes] created this sort of astrolabe in 1542. The Latinized model of his identify is [Petrus Nonius]. What are the chances of him inventing… oh wait, they named it after him. That does make extra sense.
The nonius is a collection of concentric circles traced on the instrument. Working in direction of the middle, every circle has fewer divisions than the earlier one. In reality, if the outer ring had 90 marks for 90 levels, the subsequent ring would have 89, and the next one would have 88.
The astrolabe’s line, the “alidade”, would cross all these circles however could be closest to at least one mark on one circle. Given that mark and that circle, you would search for the right reply.
For instance, the picture exhibits such a system from [Nunes] himself. It exhibits the circle from 37 levels to 38 levels. You can see the 89th circle has just one mark for 37. The different marks are in different sectors of the outer ring. The 88th, for instance, has two marks for 36 and 37.
On ring 65, the road runs proper over the 27, which is tough to learn as a result of the road covers it up. With a desk lookup, you’d discover the right worth was 37º 23′ inside 0.08′. Not dangerous. [Nunes] was thought-about one of many biggest mathematicians of his time.
But we had by no means heard of him, which works to point out that being a mathematician just isn’t a great way to get lasting fame. [Charles V], [Nostradamus], and [John Calvin] have been all born across the identical time and, whereas not family names, usually tend to be identified at present than [Nunes].
And whereas that is attention-grabbing, it raises one other query: Why did the GOWIN software program instruction handbook name the vertical marker line on a scope hint a nonius?
Why Nonius?
Our guess is that it is a translation mix-up: Chinese 游标 can imply both a computing cursor or a vernier. Or a nonius. Someone apparently chosen the unsuitable English equal.
Of course, we figured it out. Plus, we realized a brand new phrase and somewhat historical past. So we aren’t complaining.
Astrolabes are fairly wonderful. Navigation was so vital that it drove many technological developments. Of course, measuring things normally was additionally of eager curiosity to our forefathers.
