Just a quick addendum to this thread in case people look it up as they too have problems .... the following works no matter if it is daytime or nighttime, and no matter what gain and exposure you have the camera set to.
If you are unsure if your camera is actually working / frozen ....
* First set auto gain and auto exposure!
1. if the image is very dark and your adjustments don't seem to be making any difference, then shine a torch into the scope. The image should immediately go very bright/change noticeably in brightness if the camera is working.
2. If the image is very bright and your adjustments don't seem to be making any difference, then cap the scope. The image should immediately go very dark/change noticeably in brightness if the camera is working.
Second tip, it is heaps easier to find the focus point in the daytime and with auto gain and auto exposure set. That allows the camera to instantly react to the light it is finding through your scope (even when not in focus) and will show something - even if it shows shades of grey or shape changing shades of something on the preview window.
* Start by pointing your scope at something as far away as you can. It is no good finding focus on something 30 yards away as that focus point is totally different to the focus point of stars trillions of km away. You want to point at something a long way away!
* rack the focuser fully inwards or with an SCT wind the focus knob fully in the opposite direction to the infinity symbol found near the focus knob. This means you will find focus by winding the focus in just the one direction - outwards on a refractor or newtonian or towards infinity on an SCT.
* As you get near focus, those weird shadowy shapes displayed by the camera (set in auto gain auto exposure) will firm up into the image. The auto gain and exposure ensure you end up seeing a nice sharp and correctly exposed image on the screen. Much better than manually setting gain and exposure.
Third tip, once you find the focus point, get a piece of plastic or card or tape measure and cut/measure where it came to focus. I'll leave it to you to figure out where to measure ... it obviously has to be from some fixed point on the drawtube assembly to some front face bit of the camera. Or if using a SCT count the number of turns of the focus knob to get from the focus position to fully at infinity (a marking for the infinity direction of winding will be near the knob on the back of the OTA). That measurement / template will be a good starting point for the first setup in the dark. But, it will NOT be in really sharp focus at that template / measurement position ... as in the day you focused on something far away but not at infinity! There will be a slight focus adjustment in the dark to bring stuff to sharp focus. Make a new template/again measure your focus point so next time you have an even more accurate starting focus point.