In theory, as long as you can capture 1 object in the field to provide a reference point for aligning, you could stack the images by adding rather than averaging (might need to use software like Iris)... then it's just a matter of adding up your imaging time.... and no doubt lots of patience!
Sounds to me like a big challenge, but until you try, how do know just how big?
Good on you for taking up th challenge!
Al.