Al, most definitely inadequacies in the lens.. it's just the cheapy 18-55 kit lens, so it's most likely spherical abberation or coma around the edges.
I have this lens too -to get the best out of it use it in the middle of its range - that is 24-36 mm approx and stop down at least one stop. I did not respond earlier to you processing tips question but I will now - buy Images Plus is about the best advice I can give you. It automates the calibration process so you can use darks (and not in camera NR - more time collecting those photons), flats and bias frames. It handles stacking and aligning those large RAWs with ease, will even compensate for field rotation and scale changes, in short it makes processing fun! And all for the cost of a moderate ep, get it.
Thanks for posting these. They are great. The 18-55 lens is suprisingly good. There is a little aberation, but not too bad for these widefields. Johns advice look good. I'll have to try it myself.
Anyhow, here is my attempts at processing your images. There was a fair degree of skyglow, so after conversion, stacking and digital development in IP, I passed them through ABE. That helped a lot. It was then on to Photoshop CS2 to do the levels and curves adjustments and a little colour balancing. Then back to IP for some minor star size reduction. I'm fairly pleased with the results. The crus image shows up the emu very nicely.
Here's what I came up with Mike.
I adjusted each individual frame in Photoshop, making the histogram stretch as much as possible without clipping. I did each channel (RGB) individually and kept an eye on the colour balance of the image.
Once all the frames where done I used Registar to stack them all.
Back to PS and a crop then a final adjustment of the levels and curves to bring out a bit more detail.
I think the individual RAWs where really good judging by their histograms.
The small jpg here does not do it justice as the large TIFF is much better but it's huge.
Isn't it amazing how the same images can produce such different but still great results. guys
This thread has given me an idea Mike.
If the site has the room for it would it be possible to set up a download area of raw images that could be donated for beginner astrophotographers to download and play with, to learn the ropes with quality images.
We all know what our own first DSO images were like And processing them didn't really make them that much better (well it didn't for my first ones ) So if the site had a library of donated Raws (and the Darks for them) in zip form for newbie astrophotographers to download and play with, the advantages over using poorer quality images would be enourmous. There could even be a series of shots processed by others (along with a brief processing description) for each zip to show what could be achieved.