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DIY Gen 1 Cascade P7089HP cruise ship NVD

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#1 nimitz69

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Posted 13 July 2020 - 03:26 PM

So I thought it might be interesting to chronicle my construction of this NVD which I plan to use to supplement the on-board star-gazing events I'm required to host as part of my Viking Cruises Resident Astronomer gig.

 

With the arrival of my EEV P7089HP Cascade tube from the UK I'm ready to get serious about the build.  I plan to use  my ENVIS M703e ocular and a C-mount attachment for the objective lens assembly so that I can experiment with my DSLR, CCTV & ENVIS lens to see which work the best. I might also switch to a PVS-2 ocular if someone can explain to me why that would be 'better' than my ENVIS ocular?

 

This will also finally force me to learn a 3D  s/w program since I'd like to try and print some of the parts like the main tube housing, battery compartment and front & rear caps on my 3D printer.

 

The next 2 things I need to source are some sort of C-mount adapter that has female threads and can be mounted to the end of the main housing tube, so roughly 3" in diameter and some sort of 6V battery wiring harness.

 

I plan for the main housing to have an integrated plate with threaded insert for a standard photography mount. this NVD will end up being somewhat heavy, especially if i end up using my Vivatar 70-210 zoom so tripod mounting is mandatory.

 

Feel free to jump in with suggestions/questions and maybe someone else will get 'inspired' to build one as well ...

14B3E52E-AC24-4143-9F88-3696EF9705ED.jpeg


Edited by nimitz69, 13 July 2020 - 03:27 PM.

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#2 Hilbily

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Posted 13 July 2020 - 06:37 PM

Great project!
Peruse cj7Hawk's thread here, he had posted some 3D designs.
https://www.ar15.com...-359614/?page=1

Here are some pics of mine.
https://www.cloudyni...album/13196-nv/

#3 nimitz69

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Posted 14 July 2020 - 08:33 AM

thx.  I've been through that thread - some good initial info to get started but unfortunately its somewhat old, 2012, with the last post in 2017 & most of the pics and links don't work

 

 

Maybe someone has a suggestion for the following:

 

since I have a combination of cctv c-mount & DSLR lens which cover 1x to 8x my first thought was to simply use an adapter with female c-mount threads attached to the front of the scope.  however since vignetting occurs with a c-mount for any lens faster than f/3.3 and all my lens are faster than that I was thinking I should come up with some kind of front end to attach to the objective side of the NVD to take full advantage of my DSLR lens and then another adapter so that I could also use my C-mount CCTV lens if I wanted to for 1x & 2x viewing.

 

Does this make sense?

 

Of course I could just look for a fast 25mm - 50mm DSLR lens and only have a DSLR mount front end?



#4 nimitz69

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Posted 14 July 2020 - 06:03 PM

update:   after talking some more with @GeeszserGazer I was reminded that the vignetting always discussed WRT DSLR lens & cmount is when trying to do photography and not just visual.  therefore it seems my initial idea of just using an adapter with female C-mount threads on the front of the tube would be suitable since I can then use both cctv & DSLR lens like I do now with my MOD3.

 

However, I measured the objective window on the Cascade tube and it is 27mm, the ocular window is about 33mm.  so with the increased size over the 22mm Gen tubes will I end up with an issue even for visual and should therefore look for something like a T2 - F mount adapter for the front of the tube assembly to use a DSLR lens?


Edited by nimitz69, 14 July 2020 - 06:04 PM.


#5 a__l

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Posted 14 July 2020 - 07:50 PM

Not so definitely with vignetting.
For example my Zeiss Tevidon 25 mm f/1.4 format 4/3
Inner hole for NV 28 mm, diameter of the output lens ~ 12 mm, tube diameter ~ 17 mm
Good picture. Vignetting is decently smaller than here https://www.youtube....h?v=6tJKLIkVLtE
But there is a small darkened ring.

My next comparative experiment is with Fujinon-CF25HA-1 (on the way). The lens is much heavier than Zeiss.

For example, with Fujinon-CF75HA-1 f/1.8 I do not see vignetting (for c-mount).


Edited by a__l, 14 July 2020 - 08:33 PM.


#6 nimitz69

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Posted 15 July 2020 - 12:53 PM

So some more digging on my part has revealed that the PVS-2 ocular actually mates up to the P7089HP tube as designed - no spacers or figuring out correct distance, etc. There are 2 rubber rings on the EP side of the tube which mate up with similar rings on the EP. The EP has male threads & a lock ring which was designed so that it could screw into the PVs-2 threaded housing but it should be a simple matter to connect the 2 even if I don’t get a tube threaded. All that was enough for me to go ahead and purchase a PVS-2 ocular. I will still test the ENVIS ocular as well just to be sure I use the best one

I believe I now have all the major parts inbound except for the main housing which should allow me to assembly a working version of it to determine objective lens correct spacing and once that is settled I can work on a finished design for integrated housing, battery/switch & tripod mount.

Edited by nimitz69, 15 July 2020 - 12:54 PM.

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#7 Hilbily

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Posted 15 July 2020 - 09:57 PM

I went with the PVS2 ocular, much less distortion than the loupe and Plossl I was using at first.
If you use the cctv lenses you need to look for the harder to find 1" format lenses, the smaller format lenses will choke the light.
Here are some 3D files David posted for different cascade parts, you can download the STL files or have Shapeways print them as I did 7 years ago.
https://www.shapeway...ps/dropbeartech

You will be surprised when you get it fired up!
With a gain of 100,000 they are no slouch and unlike other Gen 1 devices.

#8 careysub

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Posted 16 July 2020 - 08:17 AM

I went with the PVS2 ocular,

Where are do you source the PVS2 ocular from these days?



#9 careysub

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Posted 16 July 2020 - 10:55 AM

BTW, this UK outfit provides a kit for building a complete unit -- all together, or piecemeal, but the prices are high for what they are ($550 for the kit without tube):

 

http://www.starlight...ght_scopes.html



#10 cnoct

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Posted 16 July 2020 - 11:11 AM

Nice going nimitz69, I like where your headed. 



#11 nimitz69

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Posted 16 July 2020 - 01:02 PM

Where are do you source the PVS2 ocular from these days?


The same way I acquired a non working ENVIS M703e to get my ENVIS objective for my MOD3C and ENVIS ep I was first thinking of using .... 36 yrs and counting in the USAF has allowed me to cultivate many friends in low places who I’ve made sure owe me favors ... not a traditional ‘purchase’

Edited by nimitz69, 16 July 2020 - 01:04 PM.

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#12 nimitz69

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Posted 16 July 2020 - 01:09 PM

Thx! I’ve heard many times this 100,000 gain Cascade tubes are pretty intense to look through .... maybe not the Gen 3 WP equivalent some Interneters claim but way ahead of a non cascade tube Gen 1
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#13 nimitz69

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Posted 16 July 2020 - 01:13 PM

I went with the PVS2 ocular, much less distortion than the loupe and Plossl I was using at first.
If you use the cctv lenses you need to look for the harder to find 1" format lenses, the smaller format lenses will choke the light.
Here are some 3D files David posted for different cascade parts, you can download the STL files or have Shapeways print them as I did 7 years ago.
https://www.shapeway...ps/dropbeartech

You will be surprised when you get it fired up!
With a gain of 100,000 they are no slouch and unlike other Gen 1 devices.


I found those a.ready but not sure I want to spend the money yet, I also found the StarlightNVD site but their kit is pretty pricey ...

#14 nimitz69

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Posted 16 July 2020 - 03:04 PM

so things are starting to get more interesting ...

 

another one of my 'friends in low places' just contacted me and claims to have a Gen 1 Starlight Vietnam era PVS-2 rifle scope that is fully functional.  since this is a U.S scope it has the Vario tube in it not the British P7089HP but he says its pretty amazing to look through and wanted to know if he could see the comet with it.  since tonight is supposed to actually be the first clear night in 2 weeks I was going to open my observatory and try for some images so I told him to bring over and we'll see.  I hope he has a way to mount it as I don't look forward to try and hold it since its supposed to weigh like 7 lbs ...

 

if he shows, I'll post a report tomorrow.  it will be cool to put my MOD3C side-by-by side with it ....



#15 nimitz69

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Posted 17 July 2020 - 12:44 PM

Well we didn’t ge to look at any comets last night as it’s not high enough yet to clear my neighbors house. However, it was clear so we got to look at plenty of sky.

I now see why there are some who like to compare this to Gen 3. When you look at the two side by side ther is clearly a capability difference between the two but the PVS-2 With Casacde tube was impressive in its own right. It easily showed hundreds of stars in a area viewed naked eye i could barely see 20-30. There is no gain control so bright stars like Vega were very bright light beacons. At very short ranges, under 25 yds, there was a noticeable fisheye effect but as you increased distance the field became flat to the edge. At infinity, if there was edge distortion it wasn’t distracting at all.
The tube is powerful enough that on very bright stars you’d get a ‘light painting effect ‘ or what I’d call star worms if you moved teh scope around rapidly like I did because of it being handheld. The overall image did seem less sharp than my MOD3 but I suppose that is a product of the objective lens and eyepiece, not the tube. It will be interesting to see if that changes using a modern lens as the objective along with the PVS-2 ocular and/or if a more modern eyepiece from my ENVIS M703e makes any difference either .

Given that the P7089HP is a better tube than the Vario I can’t weight to see what that looks like as well.

If someone is looking for an inexpensive NVD solution this should be considered. The only real negative is you can’t use it handheld as it weighs 7lbs but coming up with a simple bracket for tripod mounting should be easy as the adapter on the bottom of teh scope for mounting it to a rifle comes off with 2 screws and you could easily replace that with a plate that has the standard photo tripod threaded hole

Edited by nimitz69, 17 July 2020 - 12:50 PM.


#16 nimitz69

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Posted 18 July 2020 - 11:51 AM

ok, my 4 AA battery box arrived allowing me to test my tube and it fired right up with a nice green glow that lit up the small closet I was in.

 

So now I need a battery lesson ...

 

1. I assume that since the tube needs 6v to operate any combination of batteries that produce 6V are ok?

2.  Assuming that's true than does the amount of mA of the battery determine how long they will last for a particular application?

3.  While the 4x AA battery box solution works its not the lowest profile.  I could get 2 CR123A battery holders & wire them in series or even better would be something like this dual CR2032 3v battery holder with switch:

https://www.amazon.c...95090819&sr=8-4

 

So it it just a matter of duration of the particular battery type and 6v is 6v or do I need to worry about more than that?  I really should have paid more attention in my one EE class .... frown.gif



#17 highfnum

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Posted 18 July 2020 - 02:43 PM

these tubes are a lot of fun

you can clear a lot of distortion by putting aspherical lens near output screen

p8079 has pin distortion

aspheric lens has barrel distortion  

the two can cancel out if numeric opposite 

see pics

aphericlens.jpg

p8079lens.jpg

 

 

 


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#18 highfnum

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Posted 18 July 2020 - 02:45 PM

before and after

aa.jpg

bb.jpg

 


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#19 highfnum

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Posted 18 July 2020 - 02:50 PM

my final 

i placed union jack to tip hat for a great English tube 

p8079s1.jpg

 

 

 


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#20 Hilbily

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Posted 18 July 2020 - 04:46 PM

Where are do you source the PVS2 ocular from these days?


I got several off Ebay, from a seller in Israel.

#21 Hilbily

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Posted 18 July 2020 - 05:13 PM

ok, my 4 AA battery box arrived allowing me to test my tube and it fired right up with a nice green glow that lit up the small closet I was in.
 
So now I need a battery lesson ...
 
1. I assume that since the tube needs 6v to operate any combination of batteries that produce 6V are ok?
2.  Assuming that's true than does the amount of mA of the battery determine how long they will last for a particular application?
3.  While the 4x AA battery box solution works its not the lowest profile.  I could get 2 CR123A battery holders & wire them in series or even better would be something like this dual CR2032 3v battery holder with switch:
https://www.amazon.c...95090819&sr=8-4
 
So it it just a matter of duration of the particular battery type and 6v is 6v or do I need to worry about more than that?  I really should have paid more attention in my one EE class .... frown.gif


6 volts is 6 volts, internally the tube transforms it up to a very high voltage.
I wouldn't use the coin cells, not very much current in those, they may or may not work for very long.

When the batteries go down it gets dimmer.

#22 nimitz69

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Posted 18 July 2020 - 05:25 PM

6 volts is 6 volts, internally the tube transforms it up to a very high voltage.
I wouldn't use the coin cells, not very much current in those, they may or may not work for very long.

When the batteries go down it gets dimmer.


That’s kinda what I was a summing but figured I’d ask. There is a flat battery box with switch that holds 4 AA that I’ll probably get as its nice and flat

#23 nimitz69

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Posted 18 July 2020 - 05:27 PM

these tubes are a lot of fun
you can clear a lot of distortion by putting aspherical lens near output screen
p8079 has pin distortion
aspheric lens has barrel distortion  
the two can cancel out if numeric opposite 
see pics
attachicon.gifaphericlens.jpg
attachicon.gifp8079lens.jpg


So that looks like a magnifying glass lens? If so, what magnification power did you use?

#24 highfnum

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Posted 18 July 2020 - 10:31 PM

not quite a magnify glass 

it got a steeper slope

 

30mm in diameter

if my memory is correct 45mm FL

ill check as soon as i can 



#25 nimitz69

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Posted 19 July 2020 - 07:59 AM

Thx. Do you remember where you got it?


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