Pagman wrote in post #18494380
So I would be ok pushing the Iso 6400 or even higher Remember its a crop body not full frame, collecting lots of frames wont be a problem - every clear night I will just keep adding to what I have taken and keep the RAWS.
I really appreciate your help and info - thank you martin.
You have no choice but to increase ISO. You cannot expose longer without a tracker. You cannot open up faster than F4. So your only choice is to increase ISO. Doesn't matter if it's a crop or not. It's all you can do at this point. So if you want data, you will need to increase ISO as high as it goes, and look at your histogram to get it close to 1/3rd filled from the left. Then get a ton of exposures. Literally, try to get an hour of data. The stacking process will help with the noise from high ISO. You will need lots of signal to noise ratio to be able to pull nebulosity out, but you may be able to see a decent bit of it even at the highest ISO your sensor can muster, with enough exposures stacked to increase the signal. 3600 exposures will give you 60 times the signal of a single exposure. That's what you need to be shooting for. Obviously beware, adding a lot of miles to your shutter on your camera doing this. Also, you really, really have to learn to process the data once you acquire it. It's not a magic bullet, it takes almost as much time to process to get the data as it does to acquire it. Again, see the tutorial I posted and specifically pay attention to the parts about curves & levels (requires measuring).
The alternative is to get a shorter, faster lens (such as an old M42 mounted, like a Vivtar 135mm F2.8 for cheap), or to get a tracker (Star Adventurer or iOptron SkyTracker, etc).