M33 from Kent

[MarkS]

It seems everyone has had an attempt at M33 this year!

Here's my version: 58 x 5min with modded Canon 350D on Takahashi Epsilon 180ED using IDAS LP2 filter.

Taken on 9 Oct 2013 - I left it imaging during the night and set the alarm to wake me for Comet ISON.  But Comet ISON was clouded out.  Unforunately the temperature dropped overnight so the later frames were softer focus than the earlier ones.



Larger version (original size but cropped) here:
http://www.markshelley.co.uk/Astronomy/2013/m33_09102013.jpg

Mark

[Ivor]

Excellent result, you have done a great job of bringing out the arms.  What did you use for the processing are you still mainly using IRIS?

[RobertM]

Very nice that Mark, shame you lost some frames due to focus and cloud as you might have been able to tease out some more background detail.  Lots of very faint fuzzies showing in the background too.

Robert

[MarkS]

What did you use for the processing are you still mainly using IRIS?

Interesting question!  I experimented with PhotoShop on this image but only for the final stage.  All the main processing was done with IRIS and in IRIS I also added a very blurred version of the whole image onto the original to give more macro structure to the spiral arms and to make the very faint outer regions more distinct.  But this lost contrast in the dust lanes near the core so in PS I selectively subtracted the blurred image nearer the core of M33 using layers and a huge soft brush (800 pixels in diameter) with low opacity.

The overall concept is similar to that of PixInsight's Multiscale processing with HDRWaveletTransform but in my opinion this tends to give results that are far too harsh and very obviously done by HDRWaveletTransform.  

Mark

[Carole]

Very nice Mark.  It's not a straight forward object to process is it?  Even my OSC version took several layers of separate processing similar to what you describe, and as for the LRGB one even more tricky.

You've some very nice detail in the core and several Ha areas showing nicely.

I do miss DSLR imaging, but unlike yourself could not overcome the noise problem. 

Carole

[JohnP]

Looks great Mark - Colours look spot on as well. Not sure if I can see just a hint of 'vertical banding' on full size but a corking image - John

[MarkS]

Yes, the infamous Canon vertical banding is present - I forgot to perform a final "vertical band removal" stage.

[Carole]

the infamous Canon vertical banding is present

Are you still saving to the SD card Mark?  If not are you downloading to the laptop and if so do you still have the SD card in place.  i.e. do you remember a previous conversation about the effect the card might have on DSLR banding when left in place?  Once I removed my card the problem seemed to go away. 

However this is not the same sort of banding that I used to get.

Carole

[MarkS]

Good point Carole - I am using the SD card and I need to re-check this.

I'm sure I previously did some experiments and decided my particular SD card was not causing problems.  But my memory fails me.  I need to keep a proper diary of such experiments!

[The Thing]

Lovely picture. I never see banding in my images - far too much noise!

... But my memory fails me.  I need to keep a proper diary of such experiments!

You could add a blog to your website as we are all fascinated by your mad scientist investigations and love to hear the results!

[julian]

Very Nice Mark

[Mike]

Very nice Mark. I agree with Duncan about documenting your experiments.

[Fay]

Very nice Mark.

[mickw]

Nice one Mark