Tuesday, July 29, 2008

Help a brother out.

Surely somebody who reads this blog has experience running night-vision gear behind a magnifying optic.

Frank James has a super neat-o stealth hog hammer project that has run aground due to problems with groups wandering unpredictably when shooting with the PVS-14. By daylight, the thing shoots like a house afire with just the Zeiss optic, but when he puts the see-in-the-dark gear behind it, point-of-impact heads off for parts unknown.

Is it a basic incompatibility between the magnifying optic and the NOD, or what?

18 comments:

Anonymous said...

Don't NVG transmit to the eyes via a camera of sorts and not straight through optics (think watching a scene through a CCT vs a scope)? That would make "eye placement" extremely important for consistency's sake. I put "eye" in quotes because it really means the "eye" of the NVG.

I just checked his 2nd link and it looks like he's already working on that possibility...

Chris

pdb said...

That never happens in Counter-Strike, so I don't think I can help here.

Tam said...

PDB,

I'm crossing my fingers. A stroll through the site meter here on a given day is full of .mil and .gov hits from all manner of sunny and sandy locations; hopefully someone will know someone who can provide an answer.

Everybody I know stateside who has a NOD setup on their carbine is running it behind a zero-magnification parallax-free optic. My NVG's are crappy 1st-gen Russkie goggles, so I'm no help.

Dr. StrangeGun said...

I left him my theory that it could be that the PVS14 is "watching" infrared and the focal point has shifted due the longer wavelength. It's a kind of chromatic aberration.

I'm well familiar with the effects; my scrip sunglasses are regular plastic so I could get them dark. It's slightly disconcerting to see brake lights floating what seems to be an inch or two above the surface of the vehicle in front of you; similarly, anything blue seems to be depressed into it's surface. If I move my head around, the red and blue objects shift as well, depending on what part of the lens I'm looking through.

Farmer Frank said...

Tam: Thanks. I'm getting some feedback on the blog. One idea I haven't tried is putting the NVG in FRONT of the Zeiss. That I'll do tonight.

Thanks again,
All The Best,
Frank W. James

Andy said...

Assuming the ZIQ(Zeiss in Question)is magnified, you need to use the 14 in front of the scope. Happy poaching.

IZinterrogator said...

Everytime I've ever seen a magnifying scope with night vision in my capacity as a .mil guy, the NVG is either in front of the scope like a AN/PVS-22 or it is the scope, like a AN/PVS-4. I've never seen a magnified optic placed in front of the NVG, just EOTechs and Aimpoints. I called ITT Night Vision, one of the makers of the PVS-14, for you. Their tech support guy wasn't in, but as soon as I started talking about the issue, the guy who answered said they didn't recommend that. If you want to follow up, the number is 540-561-0503 and you want to talk to a guy named Billy Williams.

Tam said...

"I called ITT Night Vision, one of the makers of the PVS-14, for you. Their tech support guy wasn't in, but as soon as I started talking about the issue, the guy who answered said they didn't recommend that. If you want to follow up, the number is 540-561-0503 and you want to talk to a guy named Billy Williams."

That's what I'm talking about: Behold The Power of Teh Intarw3bz! :)

Tam said...

Andy,

"Assuming the ZIQ(Zeiss in Question)is magnified, you need to use the 14 in front of the scope. Happy poaching."

In many parts of the country, feral hogs have become such a problem that Fish & Game would give you a medal if you went after them with claymore mines after midnight...

Alec said...

I've got a little experience using PVS-14s on day optics.

"Assuming the ZIQ(Zeiss in Question)is magnified, you need to use the 14 in front of the scope. Happy poaching."

That's not true. Not with a PVS-14 anyway. It will look like it's working, but what appears to be under the crosshairs will not acutally be under the crosshairs. UNS type NVDs go in front, PVS-14s have to go behind the magnified optic.

A change in zero once the '14 is mounted is to be expected, you just have to have your day dope and your night dope. If I read correctly, the change is unpredictable, and not even the same from shot to shot. I don't know what to say about that.

Farmer Frank said...

Day dope and Night dope? Okay, I have noticed the difference in POI is approximately 4" at 100 yds, so that kinda makes sense. It's just that it's never on the same position on the clock face, which is what is driving me nuts. I'll find out tonite after dark whether the front position works. If it doesn't, then I'll try and find a predictable "Night Dope" position in relation to my "Day Dope" position.

Thanks for the input, this is a steep learning curve for a fat old farmer.

Oh yeah, the Feral Hog Eliminator when used as designed will be with the blessing and annointing of the authorities. Feral Hog are a looming ecological nightmare for certain parts of the country and we hope this project help solve part of the problem.

All The Best,
Frank W. James

Kristopher said...

I don't think putting the optic behind the scope will work well ... you are looking at a magnified image of a screen inside the optic.

What you need is a simple magnifier to put in front of the eyepiece.

That or a better nightvision device ... I would suggest an Elcan/Raythion thermal image rifle scope if you have $11,000 burning a hole in your pocket.

The Elcan folks are canucks, so you will want to pony up some official looking paper to make them happy about selling to you ... a letter from your game warden requesting help with feral pig control will work.

gmcraff said...

Slightly around the side of the topic but in keeping with the posting itself, is it now standard for the People of the Gun to refer to each other as Brothers and Sisters?

"Brothers and Sisters! Can I get a cease-fire? In accordance with Rule Two, I need to place something down-range that I wish to destroy, canIgetanAmen?"

Tam said...

You preach!

Scot J said...

Go talk to Victor of Tactical Night Vision Company, he runs alot of different setups. He has his own site and a board on the arfcom industry forum. Personally when I get a -14 I am going to buy the USGI 3x magnifier with it, made for the -14 and compatible with a dot sight in front of it.

og said...

Boss: Is it an eye relief issue? have you tried moving the scope forward so the exit pupil of the modified optics is at the same point as the exit pupil of the unmodified optics? you obviously have your cheek on the same place on the stock, but maybe you're inside the optimal point of focus, and that skews the POI around.

Don't know nuttin bout nightvision, but I play with telescopes all the time.

Anonymous said...

God, it's weird to read a blog and have a commenter suggest contacting the company I'm reading the website from. It's a small world!

Hello from ITT NV :)

IZinterrogator said...

That's what I'm talking about: Behold The Power of Teh Intarw3bz! :)

No, that post above is The Real Power of Teh Intarw3bz. :p