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Joe McQuade

Nuts for 'Nocs -- Using the Fujinon Range Guages

2 posts in this topic

A recent exchange with a friend, who had admired my binoculars on a recent boating excursion, produced a lively discussion among us and others:

Friend One:

Hi again Joe. Forgive me for my digression, and if I'm maybe more interested in your boat binoculars then you want to entertain, but that's some cool beans you got there! Only if you have it handy please email me the make and model number on those. I don't own a boat but I still want a pair of them - and given enough time I'll rationalize the cost.

I truly believe that the grid you see when you look through them is calibrated in milliradians. (Then again it could be calibrated in Minutes of Angle (MOA), but that's a whole different math equation and I don't think that's the case based on my brief play time with them.) So anyway a milliradian equals 1 meter at 1000 meters. When you look through the binoculars you estimate the milliradian size of the object you're looking at (height or width) off the grid, do the math, then you have a good estimate of how far away the object actually is.

If the grid is calibrated in MOA it's the same concept, but the math is somewhat harder there since one MOA equals 1.06 inches at 100 yards, or 10.6 inches at 1000 yards.

Just curious as always . . .

Joe:

Glad to see another binoc freak. As a Fujinon evangelist, I've probably sold 10 pairs of these through the years....

They're the reference standard in marine (and any outdoor) binoculars: The Fujinon 7x50 FMRTC-SX, about $600.

Here's the Fujinon link to the FM series: http://www.fujifilmusa.com/products/binocu.../fmt/index.html

Here's the Amazon link: http://www.amazon.com/Fujinon-Polaris-Bino...o/dp/B0002GTTF4

Higher power nocs are too shaky on the water and even on land for most. The optics and light-gathering capabilities are breathtaking. They really perform most remarkably at dusk and at night. Get a tripod adaptor and a solid tripod and leave them at your deck window for birdwatching and the like. The boys will go bat shit. Remember your own focus settings for each diopter, and everything's in focus from 50 feet to infinity. Diopter adjustments need only be made for objects under 50 feet away.

Here's what my manual says about the vertical scale (reticle). You need to know either the distance to the object or the height of it for it to be useful.

"Each mark on the reticle has a value of 5 MIL (1 MIL is equivalent to an angle that can determine an object one meter high at 1000 meters). (DON'T WORRY IF YOU DON'T GROG THAT!)

"To measure distance when target object height is known:

"{Object Height (m) divided by scale reading} x 1000m = Distance in meters.

"To measure object height when distance is known:

"{Distance (m) x Scale reading} divided by 1000 = Object height in meters."

In sum, a six foot man fills just under two hash marks at 1000 yards, under four hashes at 500 yards, six at 250 and so on. To be precise, a two-meter tall man filling four hash marks would be 500 meters away (2/4 x 1000). A man known to be 1000 meters away filling two hash marks would be two meters tall. {(1000 x 2) / 1000}.

Also, don't forget there's a horizontal scale there, too, that concerns width of objects with the same formulae.

Keep me posted!

J.

P.S., I'm copying this to Friend Two and Three, who are using their nocs to great effect at their beach house in Galveston. Let's measure heights and distances in the Bahamas, dudes!

Friend One:

Thanks Joe! All cool stuff.

I've always been into binoculars, and the same concept carries over into rifle scopes. I'll of course check things out fully (in my copious spare time if may I add that) and get back with you. The 5 mil vs. 1 mil grid is no problem, I know that 1 Mil equals 1 Meter (height or width) at 1000 meters, so the math there is easy. If you can estimate the height of the object off the binocular grid (however it's calibrated), then you can closely estimate the distance to the object – or of course do it the other way around. For the basic stuff we're talking about, it's almost that easy.

On this topic I did read an interesting article the other day about these US Marine snipers that can pick off guys a mile or so away though. They use similarly calibrated Mil grid scopes for all that, but they also have laser designators where they can beam the target and get the exact distance. But even knowing that, they then need to be concerned about bullet drop at that distance, wind speed and angle, air temperature, elevation, humidity, barometric pressure and sh$t like that. From what I read once you get past a 1000 yard shot you even pretty much even need to know what your lat and long are - since the relative curvature of the earth actually comes into play at those ranges! (I forget who said it, but it goes something like: "The more I learn the more I learn how much I DON'T know.")

Again, all good stuff and thanks.

Another from Friend One, with Joe's replies in blue:

OK then.

Several beers and a few hours of Internet research time later, I've fully justified my pure and simple need for a pair of those binoculars. I'll likely be up most of the night anyway as it seems number 2 son Jack is throwing up every hour - pretty much on the hour. (I'd blame it on the pizzas we all had, but everyone else is fine so far, so I guess it's just a stomach bug he caught.)

God bless him though, the only reason I know he's sick is because I was up anyway. The bathroom light goes on, I hear him barf, then I hear the toilet flush, otherwise no whining or anything. I've gone in there the past couple of times and there he is just washing out his mouth and wiping his puss off. I ask if he's OK and he basically responds "Yeah, I'm OK dad. I just threw up, but I'm going back to sleep now." (God I love that kid!)

That's one tough little hombre. He'll be good in the foxhole with you when Paul Ryan/Rand Paul safety net "reforms" kick in and armed geezers & the unemployed are roaming the land in search of food and shelter.

Anyway back to the binoculars. I'm still very solid with my 1 Mil = 1 meter at 1000 meters calc, that seems all solid from everything I've read.

Remember the manual's claim that each hash represents 5 mil? So at 1000 yards a 5-meter-tall structure such as a channel entrance marker or a hefty shrimp boat would fill only one hash. That seems a bit small in my foggy recollection, but we'll see...

I did get a little hung up on the whole "angle that can determine" concept,

I'm still hung up on it, which is why I seized on the formulae, which made more sense to me. I noticed, but sneakily chose to ignore, the problem you're about to raise...

but it appears that only comes into play if you're far above or below the object's elevation (on height), or at a serious angle of deflection on width. In those cases then you need to factor the cosine of the angle into the range estimate. But if you're looking at it dead on, and not way off on elevation or azimuth angle (way off being more than 30 degrees), then it's basically just a rounding error.

This is the shit I didn't want to get into, because I felt a massive dode coming on during yesterday's e-mail -- and because I've forgotten most of it from my pre-GPS days. Height of eye is a crucial factor in maritime height/distance estimates. A guy 100 feet up on a tanker bridge is going to see much farther over the horizon than a dude getting a blowjob in a Catalina 27 cockpit. Tables exist in the Bowditch reference book and elsewhere that account for HOE. I used to have a circular plastic range calculator with monocle. I think it also had sliding wheels that let you enter HOE and object height or distance. In slide-rule fashion, it would give you the third value. By the time I lost it, GPS was so ubiquitous I thought it was more important to work on my drinking-and-sailing skills than to hone my ancient, never-used-except-to-impress-chicks dead reckoning techniques. My old-school mentor, Jack Davis, scoffs at such hip-hop insolence. He says every GPS should be sold with a small mirror, so when the electronics fail you can look in the accompanying glass to see exactly where your dumb ass is. I took his advice to heart, after a fashion. I always have at least two GPS units.

I am interested to see what your results are when you play with them on your Bahamas trip. You can estimate things, then confirm it with the GPS. Please let me know what you discover.

Will do. By the way, I need to modify my oft-voiced claim that TiVO is God. Actually, GPS is God the Father and God the Son (Patris et Filii). TiVO is the Holy Ghost (et Spiritus Sancti). Jim Beam is Michael, the Head Archangel in Charge, and so on...

Joe

Friend Four (who was copied in on the previous exchange):

HI ALL , after scanning all this BS, I decided everyone is crazy!!

Anyone want to borrow my nocs? They show bearing

Joe:

As Jack Benny would say, "Now, wait a minute!" I rescanned all the BS, too, and there appears to be a conflict between the 5 mil per hash claim and the formulae.

The following two claims don't square. Which is wrong?

a) "In sum, a six foot man fills just under two hash marks at 1000 yards, under four hashes at 500 yards, six at 250 and so on. To be precise, a two-meter tall man filling four hash marks would be 500 meters away (2/4 x 1000). A man known to be 1000 meters away filling two hash marks would be two meters tall. {(1000 x 2) / 1000}.

b) "Each mark on the reticle has a value of 5 MIL (1 MIL is equivalent to an angle that can determine an object one meter high at 1000 meters)."

Friend Five (also copied in previously):

The best nocs are ones that bourbon drinking dime novelists leave on your sailboat thinking they're broken.

Friend One:

There's no question at all in my mind that 1 MIL is 1 Meter at 1000 meters, and I believe this is just poor writing / translation in the manual.

If I recall the grid in those binoculars is marked and labeled every 5 MILs, but has a small hash mark for every MIL. (See my poor example below.) If you assume a) refers to the small "hash marks" and the first part of b) refers to the numbered (big) "marks" everything above can be interpreted consistently. It's easy enough to test also, assuming the binoculars are in hand.

| --

| --

| --

|------------ 10

| --

| --

| --

| --

|------------ 5

| --

| --

| --

| --

| ----------- 0

And by the way, you can still drink, surf the net, and talk binoculars all at the same time!

Joe:

Me likey. I'll test it when I get my nocs back tomorrow. They're down at Dickinson Bayou at the moment with Friends Six and Seven…

The Bahamas tests begin Wednesday.

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