Hmmmmm, where do I start with this...
On Saturday , I did my experimentation.
I have taken darks in full light and at night in very dark conditions and of varying lengths, ie 2 sec, 5 minutes, 15 minutes and 30 minutes. All consistently saturated if exposed to light before taking the dark, but the second or third dark was fine.
The duration and intensity of the light source affected the overall saturation of the image. For example, with no filter and a Compact Fluorescent Lamp (CFL) turned on (ie very bright conditions) it was fully saturated across the whole sensor. With my Oxygen filter in and a very brief flash of the CFL, it was about 30000 ADU. I also partially exposed the sensor to bright light and got a roundish pattern with dark bits at the bottom corners which corresponded to the round sensor cover.
That photo attached before was a 30 minute exposure of the eagle through an Oxygen filter. There is an old fluro in the kitchen about 5m from the scope that caused that bleeding. (I looked up the spectograph thingy of old fluros and they seem to emit very strongly in Red wavelengths) Originally, I thought it was the Oxygen filter because over the past couple of weeks, I have used the Ha filter with no such effect. However, last night I used the Ha filter again and got a similar pattern. However, later on in the night, I took a 30 minute sub of the Horsehead with no issue whatsoever... And that was pointing towards the waning gibbous moon and a streetlight across the road. However, the fluro in the kitchen was off... So I am certain that the fluro is causing that issue.
There doesn't seem to be any light leakage.
The problem is that the
sensor is registering light when the electronic shutter is supposed to be closed. It's almost as if the pixels are never turned off. And this is consistent across both my laptop, which I use in the field (and in the backyard) and my main tower which I use to take darks on.
Now, I know very little about the internal workings of this camera. When it says "electronic shutter", does that mean a physical thing or is it a "digital" thing that stops the pixels detecting photons...
And yes, the funny pattern only hangs around for the first image.
In regards to the desiccant chamber, I tried to remove it to bake it in the oven as I was getting fogging on the glass of the camera when imaging at -15 degrees. It has been very humid up here in Brisbane recently. I used a flat screwdriver . It came partially out and then stuck. The screwdriver then proceeded to take great gouges out of the slot. So I screwed it back in and left it.
So,
Cheers,
DJ Scotty