In your last thread you also posted an image of stacked 300secs Orion with an immensely blown out core.
http://www.iceinspace.com.au/forum/s...53#post1399153
Someone then suggested you do shorter subs.
So, in order to test your improved, i.e. shortened imaging procedure, you could now try and stack only the shorter subs you took and see what results you get. Leave out the ones with 300seconds from a few days ago.
edit: Would you like to post a single 5 mins frame?