1004x Camera
After hunting around on Google looking for a camera that would give me a chance of capturing faint objects I found some information about the 1004x board camera. Sold for just £43 through RF Concepts and with a lux rating of 0.003 I thought I’d get one and see what it could do.
The unmodified camera worked like a dream with views of M42 and Star Clusters like M15 far exceeding my expectation after failing to capture any image with the Trust SpaceC@m. After a few nights of aiming the camera skywards I started to wonder if modifying the circuit would allow me to capture even fainter objects. I found lots of refences to the JG mod (Search Google) and finally settled on Willie Koorts site to guide me through the changes.
I added both the Boost option and Manual Gain, and opted to cut pin 16 rather than attempt to de-solder and lift it. I used hot melt glue to secure wires to the circuit board to prevent unnecessary movement and picked up the components via mail order from Maplin. The whole lot fitted nicely into a maplin project box with the Mogg Adapter holding the board firmly to the underside of the lid.
I don’t have any images of the original mod so can’t show you how it looked inside the box. Although this image shows the unmodified board attached to the lid.
The mod was successful with boost giving me high noise, high gain, and manual gain giving me some control with brighter objects but Saturn and the Moon were still too bright even with a skyglow filter. I found boost to be more useful than the gain control and Registax was able to remove most of the noise and dead pixels during stacking with darkframe subtraction. I say dead pixels because I was most anoyed to find 2 dead pixels on the camera. I later came to appreciate 2 dead pixels was good!
I wanted more, I could now see really faint objects, fainter than I could make out through the eyepiece although I later found my primary was so dirty that I’m surprised I could see anything through the eyepiece. I looked around for long exposure mods, but having a dobsonian mount means you can’t track objects as they apparently glide across the sky, but rather you need to video them as the cross your field of view and then stack the results. What if I could double the exposure, or maybe 5 times the exposure surely that would make the camera exceptional? I went back to Google, and found long exposure had been done and the same names, Steve Chambers (of SC mod fame) and John Grove (JG), kept cropping up. All the long exposure mods use a parallel port cable to allow a PC or Laptop to control the exposure from seconds to minutes. I needed to increase the exposure from 1/25th second to 1/10th or 1/5th not to 5 seconds, this would lead to a streak across the screen rather than increased detail and fainter stars.
I decided to take matters into my own hands and after a quick scan through the data sheets I made a circuit based on a binary ripple couter. The idea being to intercept the clock signal that drives the frame rate and use the ripple counter to reduce this by, initially 2x but with the option through jumpers to change this to 4x, 8x and 16x.
I was too keen and visions of distant galleries clouded my judgement. I managed to bridge about five pins on the one chip with a blob of solder that just appeared as if by magic. No amount of braid, solder pumping or scraping with pins and sharp knives made any impact and attempts to get the soldering iron involved in the cleanup just made things worse. After an operation that lasted well over 4 hours I had to finally down tools and admit that I couldn’t save this one.
My wife is very understanding and after letting her know how much I would like another 1004x she finally agreed on the condition I didn’t trash it.
So after a few days waiting for the new camera I couldn’t wait to get it in the Maplin box and start imaging again. To my horror this board had at least 8 dead pixels with others which brighten as the camera warms up (hot pixels). I can’t believe I trashed the one with only 2 dead pixels! Have a look at the dark frames below to see the difference between the first and second 1004x boards.
True to my word I wasn’t about to inflict the same mods on this board, so instead tried a variation. I hadn’t had much success with the manual gain so this time I routed the manual gain potentiometer to the boost pin (14) and removed the connection to +5v. Now I had manual boost, no need to cut or lift pins, only one wire to solder to the board and a way to balance boost against noise, woohoo.
I’ve left it like that, too nervous to try anything like an extended exposure mod, but I’m happy with the results at the moment so I’ll continue to push this camera to its limits before I try anything like that again.