[Shiraz (Ray)]

Originally Posted by Atmos

It is very nicely resolved Ray! Mike appears to still have a stronger SNR but he also has more exposure

Thanks Colin. I should have given it a bit more sky time - particularly dark sky - but I was also working on 3 other projects at the time -no excuse, just a choice and it shows.

Originally Posted by Stevec35

I think that's still extremely good Ray

Cheers

Steve

thank you Steve - appreciated

Originally Posted by RickS

Looks good, Ray. I would have said "great" before Mike lifted the bar on this object Look forward to the final version.

Cheers,
Rick.

thanks Rick. am trying to understand some dynamic range issues with this camera - hopefully can sort it all out and improve the image.

Originally Posted by strongmanmike

Well it's pretty bloody close Ray!..an excellent image of this tiny blighter!



I agree Ray, the processing required on this one was indeed difficult. I also totally agree that it is always important to make sure ones processing doesn't introduce spurious, shall we say, "make believe" detail or features and yes masks and lassoing as well as Decon, wavelettes and selective curves and sharpening etc can easily create bogus features and detail when processing objects like this one...in fact most objects really? However, in science when one reveals potential new and/or faint structures etc, in fact any structures really, in an image, they mean very little until they can be confirmed in separately collected data...so, here is a comparison of my results with another very deep image taken by the CTIO guys using a 16" RC under the excellent skies of Cerro Tololo observatory at 2200m up in the Andes:

CTIO vs Wallaroo

Clearly all our structures and faint outer details match essentially perfectly...so they must be real ...also the OIII extends right into the outer shells and not just inside the central oval.

Again a great result Ray

Mike

thanks very much Mike. It is a real problem to make sure that new "features" are not introduced. That is one of the reasons I like PI so much - there are almost no mechanisms for fiddling with an image (eg no "lassoo" selection or paint facilities), so any features that creep in have their origins in the data. However, there are still user choices in mask thresholds, degree of stretching, sharpening etc that affect the outcome - so I try to stick with automated methods or mathematically sound processes such as deconvolution that are driven by measured data content rather than a whim. Also, when deciding on what is real, I always find it useful to do an automated stretch of the stacks, before any processing - that shows where the real data extends to and what general structure the dim bits have (attached). And of course, everything to do with colour is up for grabs.

On that basis, it is comforting that there is so much similarity in images of such high dynamic range (or very faint) objects.

Regards Ray