This writeup details my tinkering over the past week or so "builing" my own Astroscope for use in Night Vision Photography. If you just want to see pictures and aren't interested in an engineering project, enjoy this link (https://www.cloudyni...oscope-project/). Otherwise, thanks for reading!
I'd also like to thank jdbastro for his post (https://www.cloudyni...a-sony-alpha-7/) and for his help identifying the proper voltage regulator.
Ten years ago, when I was in the U.S. Coast Guard, I had the opportunity to use an Electrophysics Astroscope with a Canon 6D. Ever since, I've loved both Nigh Vision and Photography, and I've been dying to get my hands on an Astroscope of my own. I once tried building the entire astroscope, with the intention of using the Image Intensifier Tube (IIT) from an old set of PVS-7's. Due to some difficulties with optics, this never came to be.
I was, however, able to pick up a 10160 Tube recently, and so I began looking for a housing. I was able to score an incredible deal on a housing about two weeks ago, though it had no tube or clamshell for holding the tube.
The housing is made for a Nikon camera and lens, which isn't great given that I shoot Canon almost exclusively... So I ordered a Nikon D3400 and an 18-55mm lens. I will likely upgrade later, but these were cheap and will get me started. My plan was to use the camera to power the tube, and I also wanted to maintain autofocus capability. This requires passthrough of the leads, voltage regulation, and proper alignment of the tube. Essentially I set out to reverse engineer the so-called "Central Intensifier Unit" (CIU).
The project essentially breaks down to two separate subprojects: the electronic subproject and the mechanical subproject.
The electronic subproject had few requirements.
1. Provide continuity, through the CIU, to power the lens.
2. Provide power to IIT via pinout and passthrough pins.
3. Design circuit to step down the power from the passthrough pins to ensure voltage to IIT doesn't exceed 3.3v.
4. Provide power to ITT from voltage regulator circuit.
Continuity was trivial. I ordered 14 gauge copper rods and designed my CIU with them in mind. When cut reasonably square, and to the right length, they maintain continuity as desired.
The exact details of the correct pins aren't super relevant for this. Suffice to say it took way more tinkering for me to figure out than it should have; I soldered and resoldered the contacts like 5 times before I found the correct pins. I should have just used the ones evident in jdbastro's post...
I was able to find a voltage regulation circuit on google, and jdbastro confirmed the voltage regulator I suspected I'd need. I had to get creative wiring the circuit, as real estate was limited. This included trimming the heat sink of the voltage regulator and soldering the capacitors in a funny way.
The mechanical subproject was a bit more complex and had a few more requirements.
1. Ensure tight containment of IIT within CIU as well as tight containment of CIU within Astroscope housing.
2. Ensure alignment pins of astroscope housing have a mating hole.
3. Ensure alignment of copper passthroughs with spring loaded pins in the housing.
4. Allow for indexing of IIT within the CIU.
5. Ensure both parts of the CIU may be aligned.
6. Allow for the CIU to be bolted together.
7. Provide room within the CIU for the voltage regulation circuit.
8. Provide room within the CIU for the leads to be soldered to the correct passthrough pins.
9. Ensure the lens is able to properly focus an image on to the objective end of the IIT.
To achieve this, I 3D printed seven iterations of the CIU.
Rev. 1 of the CIU captured the internal and external dimensions required for fitment, including a method to index the two halves together and with the Astroscope housing. The indexing tab for the IIT was present here as well. It was also an early attempt to locate the passthrough pins. Locating those was a pain in the butt, lots of weird measurements and math.
Rev. 2 involved the repositioning of the IIT indexing tab, as well as the addition of passthrough pin holes. It also included a space to solder to the passthrough pins, and a place to attach power contacts for the tube.
Rev. 3 included the addition of space for the voltage regulation circuit.
Rev. 4 included an expansion of the circuit area and an enlargment of alignment pin holes. (The wires were soldered on to determine voltages when the astroscope was fully assembled)
Rev. 7 finalizes the focal length adjustments, and reduces the area for soldering the leads to the correct passthrough pins.
Finally, here are a few test shots with it. I's probably worth noting that image quality will very likely improve with a full frame camera and a fast lens.
I hope you enjoyed, and thanks for reading!
Edited by rogers92, 24 March 2024 - 10:09 PM.
