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DIY Gen 1 Cascade P7089HP cruise ship NVD

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#26 highfnum

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Posted 19 July 2020 - 04:41 PM

probably surplus shed 



#27 nimitz69

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Posted 19 July 2020 - 05:32 PM

Tried searching aspheric lens 20-50mm dia and 30-50mm fl but nothing there ..... guess I need to keep searching ...

Edited by nimitz69, 19 July 2020 - 05:34 PM.


#28 highfnum

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Posted 20 July 2020 - 06:46 PM

try edmund 

a bit more money

 

also aka condenser lens



#29 nimitz69

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Posted 20 July 2020 - 06:57 PM

Ok thx. What determined the 45mm FL and how did you attach it?

I’ve seen an aspheric Plano convex lens, do those work? Guess i could use a basic optics lesson

Is this what I want?

https://www.ebay.com...eAAAOxynRRSRIaX

Edited by nimitz69, 20 July 2020 - 07:12 PM.


#30 highfnum

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Posted 20 July 2020 - 08:37 PM

i believe surplus shed

it was a long time ago

sitting around doing  nothing 

until i got p7080hp 

turned  out to be 

a good solution 

got rid of about 80 pct distortion 



#31 highfnum

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Posted 20 July 2020 - 09:05 PM

2 inch diameter is to big otherwise your correct 

 

my lens sits close to screen almost touching 

fits inside inner rubber ring

 

AND then i have an eyepiece after it

if to far away image blurred 



#32 Hilbily

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Posted 20 July 2020 - 11:10 PM

Since you have the PSV-2 ocular that is matched to the Petzval radius of the tube output, I don't think you need a aspheric lens.
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#33 highfnum

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Posted 21 July 2020 - 12:09 PM

i was going to ask

if eyepiece is  matched then it will correct 



#34 nimitz69

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Posted 21 July 2020 - 01:14 PM

Yeah, that was my next question. That ocular has what looks like an acrylic ring that fitsinto the rubber rings on the tube and provides what I assume is the correct spacing. I’ve also decided to buy the StarlightNV.com DIY Casacade mounting tube , lock ring and c-mount adapter since it should be designed with the correct spacing for the lens.

#35 nimitz69

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Posted 12 August 2020 - 04:03 PM

ok, so after several failed attempts to get Starlight NV to sell me a couple of their DIY Cascade NVD parts I've started to source things to make it on my own ....

 

I've got a 3" aluminum tube for which I made an objective lens end cap out of PVC and fitted a C-mount adapter to the end.  this allows me to use any DSLR and/or CCTV lens that I have so I'm good there.  the one thing I still need to figure before assembly is how do I determine the proper distance between the Cascade tube end and the lens to ensure it will come to focus?

 

I thought I remember reading something about determining this or what it should be based on lens type but can't find it.  Can any of you all out there who have forgotten more about optics then I'll ever learn enlighten me on this?

 

A9C64D3F-F2F9-4BF4-B200-81D1AD20B872.jpeg


Edited by nimitz69, 12 August 2020 - 04:13 PM.


#36 nimitz69

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Posted 13 August 2020 - 07:11 AM

so I found out that the required distance for c-mount lens is 17.5mm from the photo cathode tube on the P7089HP to the lens but I'm unclear as to exactly where this is on the c-mount lens.  see my diagram for the 3 possible locations on the cctv lens. 

 

does anyone know which point the 17.5mm is measured to?

 

NVD distance.jpg



#37 cnoct

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Posted 13 August 2020 - 07:16 AM

To the lens flange, the middle of the three parallel lines draw above the tube.

Since your working with a fiber optic input window so the image stop or focal plane lies at the exterior of the out surface of this FO input window.

I'd go with CS mount standard and then use spacer to get me the c-mount standard. This ensures you'll have plenty of wiggle room built into the system, let you use cs, c and then those odd lenses that might not follow the flange to image plane distance.

Other wise you might just want to shoot for the c-mount flange to image plane standard, the standards can be accessed with a quick google search.

Edited by cnoct, 13 August 2020 - 07:18 AM.


#38 nimitz69

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Posted 13 August 2020 - 10:08 AM

Thx! The CS distance is 12.5 mmm from my research and i have some 5mm spacers so i could do that

#39 nimitz69

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Posted 15 August 2020 - 06:38 PM

so I got the opportunity to pick up PVS-2 housing that was re-anodized black fairly cheap and decided that would be a better solution ....
 
- my 4x 1.5v battery box fits in the battery compartment
- I should be able to add my own external switch
- the tube fits exactly with the correct spacers built in
- the ocular screws onto the housing
 
so the first thing I did was to cut off the front part of the objective lens housing so I could fit my own cap.  next I reamed out the hole for the switch and headed to Ace where I found a nice push button switch and a pvc cap that fits exactly over the front end of the housing.  I was just going to epoxy the c-mount adapter you see in the pic to the cap but decided to go with something that is screwed together.  unfortunately that required me to find an adapter with  male 48mm threads on the outside and female M42 on the inside.  finally found one that was in stock but looks like it will be 2 weeks or more before it arrives.
 
I also needed to drill a hole from the inside of the battery compartment to the front of the interior tube stop ring since the neg lead from the battery needs to be soldered to the metal ring on the front end of the tube.
orginial switch.jpg
this is what the original switch looks like on a StarLight scope
new switch.jpg
here's my new one
switch installed.jpg
and here it is installed - forget teh lock nut when I took the pic ...

Edited by nimitz69, 16 August 2020 - 07:42 AM.


#40 nimitz69

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Posted 15 August 2020 - 06:44 PM

interior with tube.jpg

 

here's what the interior looks like with the tube installed part way as well as the new switch.  the brass cap it what you attach the red wire lead to and you can also barely make out the small hole I drilled for the black lead to solder to the front ring on the tube, its at the 4 o'clock position next to the outer ring. luckily there is enough space for the battery compartment, wires and some kind of disconnect so that I can remove the battery compartment when needed to swap batteries.

 

with a little careful measurement I should be able to determine how much of the front housing to cut off and still be able to mount my objective lens cap. this will enable me to install the tube & wire everything up while I wait for the last M<48 - M42 adapter to arrive

 

and lastly here's a pic of all the parts laid out together ...

 

everyuthing.jpg


Edited by nimitz69, 15 August 2020 - 06:46 PM.

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#41 nimitz69

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Posted 16 August 2020 - 03:41 PM

managed to figure out a way to use the M42 - C-mount adapter and a locking ring so i went ahead and completed finishing everything except wiring it up.

 

here's what the finished front housing cover looks like from the outside.  the outside of the cap is 10mm from the cathode tube face

objective lens housing front cover.jpg

here's what it looks like on the inside with the locking ring attached

front housing cover inside.jpg

that leaves 7.5mm to the lens flange which is accomplished with a 5mm spacer and there is a 2mm ridge in front of the flange on my 50mm cctv lens which gets me to 17mm.  Unfortunately I can't use these 5mm spacers with my 25mm cctv lens because the threaded barrel is too long and hits the inside of these spacers and won't seat all the way in. it looks like I can ream out this and then that lens should fit as well.  My Nikon lens fit without issue because they have the F mount to C mount adapter

 

 

 



#42 nimitz69

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Posted 16 August 2020 - 03:49 PM

here's the spacer and you can see the 2mm sliver ridge once assembled

spacer.jpg

5mm spacer.jpg

 

NVD with all the pieces assembled.  Unit is now 3lbs 14 oz vice the 6 lbs 4 oz of the Starlight AN/PVS-2. and with the objective lens removed it is only 11" long vice 15"

complete.jpg

 

remaining steps: wire the switch & battery compartment together, solder neg battery lead to tube, mount a plate to the bottom of the unit (there are 2 threaded holes) and drill a hole to attach my photography tripod mount plate.  And finally test to ensure I can reach infinity focus ...


Edited by nimitz69, 16 August 2020 - 03:56 PM.

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#43 nimitz69

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Posted 17 August 2020 - 09:30 PM

so I managed to source the 2 battery caps and complete the tripod mounting assembly.

I put a threaded insert in a small piece of plywood and attached that to an aluminum plate which is then screwed onto the bottom of the PVS-2 housing by way of 2 threaded holes in the housing which were originally for attaching the rifle scope  bracket. the threaded insert fits a universal mounting plate on my photography tripod.  here's what the completed NVD looks like when on the tripod.  all that is left is to work up the courage to solder the negative battery pack wire to the front ring on the intensifier tube which sits 4mm from the cathode tube itself ... no problem ... smile.gif

tripod plate.jpg

mounted NVD.jpg


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#44 nimitz69

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Posted 19 August 2020 - 03:29 PM

Hopefully someone will know the answer to this question;

 

in all the build threads I've seen folks simply wire their 6v battery compartment directly to the tube .. power to the brass screw & ground to the metal ring next to the cathode but didn't the actual PVS-2s have capacitors in them?  Is the capacitor built in to the tube? what is the effect of not having one if its separate?  Just faster power draw so the batteries don't last that long? the guy who refurbs these that I got a full up restored one said the battery lasts 50 hrs but these are all original parts units except for the battery which is no longer available


Edited by nimitz69, 19 August 2020 - 03:30 PM.


#45 PEterW

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Posted 20 August 2020 - 04:24 AM

I direct connect mine, tends to generate some little static sparks but otherwise works fine. Not sure I’ve got the best lens on the back end (I used a ?10x loupe lens I had floating about).
Peter

#46 nimitz69

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Posted 20 August 2020 - 09:57 AM

Ok, thx. When i wired it up to test the tube there was no issue but when I was chatting with a guy who refurbs PVS-2s, makes a new 6v battery compartment & then sells them he talked about the “capacitor” which got me wondering ....

Yeah, if you use it a lot i’d Look for some kind of ocular that has a diopter focus ring. Way better. The original PVS-2 ocular is the best since it was designed for this tube & with teh spacing rings it fits perfectly without having to figure out spacing. Looks like WhataCountry.com has them for sale ... $109 USD ....

#47 nimitz69

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Posted 30 August 2020 - 04:03 PM

ok, finally got around to making the final electrical connections ....

 

- wired in the switch

- added a ring terminal to connect to the tube

- soldered the negative lead onto the tube ring

- ensured everything fit & was removable for battery change out with caps installed

 

all that's left to to check that the NVD will reach infinity focus & find a nice case for transporting it around the world ... dalek12.gif

 

tube connection.jpg

soder.jpg

battery compartment.jpg



#48 nimitz69

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Posted 30 August 2020 - 04:03 PM

done.jpg



#49 nimitz69

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Posted 01 September 2020 - 08:56 PM

Ok, managed to get out last night between all the clouds and find a small patch of clear sky to test ...

My 50mm Fujinon, 135mm Nikon and 70-200mm Vivitar all came to focus without issue. Also checked my 640nm LP filter and it worked as well. Didn’t get to try out my 7nm Ha filter. Given how dark the skies are at sea when the ship lights are turned off for my star gazing events I may not need the LP at all.

So it looks like I’m good to go and can safely sell my refurbed PVS-2. It will also be interesting to do a side by side comparison with my Mod3 when we get a clear nigh5 here

Edited by nimitz69, 01 September 2020 - 08:57 PM.


#50 PEterW

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Posted 02 September 2020 - 03:03 PM

Interesting to see how the hydrogen filter works.

Peter


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