M33

[prabhakar]

Here is the first version of M33 captured over two visits. (LRGB - 3.7 hours)
Galaxy arms are not resolved very well, kind of challenging for me to process.
As always, thank you for taking the time to look and all comments/criticisms are welcome.

Capture Details
http://www.astrobin.com/134034/B/

Full resolution
http://www.astrobin.com/full/134034/B/

[Alvinillo]

Nice shot and good color balance. I think the background is too dark, it looks like clipped. Natural background includes some signal.

It would be nice to enhance galaxy arms. Maybe Contrast module could help, not sure. HDR or Large scale Sharp could also be helpfull

Regards

[prabhakar]

Thanks Alvinillo, I will redo this target with your suggestions.

[admin]

Great colors and detail indeed! Have to agree with Alvinillo that probably the only flaw with this image is that there is some pretty bad clipping going on. I'm wondering what caused this (as it's pretty hard to clip your data in StarTools). Was this image processed fully in StarTools? Did you maybe use AutoDev with an ROI and 0% Outside Influence?

[prabhakar]

Ivo,
Yes after stack this is fully processed with startools.
In Autodev i set outside ROI to 15% i guess.

Here's the fits, if you would like to take a look.
http://www.astrobin.com/tmpzips/10e40bf ... -11eea.zip

[admin]

Ivo,
Yes after stack this is fully processed with startools.
In Autodev i set outside ROI to 15% i guess.

Here's the fits, if you would like to take a look.
http://www.astrobin.com/tmpzips/10e40bf ... -11eea.zip

Thanks, but it appears the zip is no longer available...
If you could post the StarTools.log part relevant to this image we can also pin point why parts of the image appear clipped.

[prabhakar]

Ivo,
I've pm'ed the link, hopefully it stays up.
Your inputs will be very useful to figure out where i clip the levels..

Here's log of my processing steps.

File loaded [F:\Astro\work\M33-LRGB.fit].
---
--- Auto Develop
Parameter [Ignore Fine Detail <] set to [Off]
Parameter [Outside ROI Influence] set to [15 %]
--- Wipe
Parameter [Mode] set to [Correct Color & Brightness]
Parameter [UNKNOWN] set to [Yes]
Parameter [Precision] set to [256 x 256 pixels]
Parameter [Dark Anomaly Filter] set to [3 pixels]
Parameter [Drop Off Point] set to [100 %]
Parameter [Corner Aggressiveness] set to [100 %]
Parameter [Aggressiveness] set to [75 %]
--- Wavelet Sharpen
Parameter [Intelligent Enhance] set to [Yes]
Parameter [Scale 1] set to [100 %]
Parameter [Scale 2] set to [100 %]
Parameter [Scale 3] set to [100 %]
Parameter [Scale 4] set to [100 %]
Parameter [Scale 5] set to [100 %]
Parameter [Mask Fuzz] set to [8.0 pixels]
Parameter [Amount] set to [100 %]
Parameter [Small Detail Bias] set to [75 %]
--- Deconvolution
Parameter [Image Type] set to [Deep Space]
Parameter [Mask Behavior] set to [De-ring Mask Gaps, Hide Result]
Parameter [Radius] set to [1.5 pixels]
Parameter [Iterations] set to [6]
Parameter [Regularization] set to [1.00 (optimal noise and detail)]
Parameter [Mask Fuzz] set to [8.0 pixels]
--- Color
Parameter [Cap Green] set to [No]
Parameter [Bias Slider Mode] set to [Sliders Reduce Color Bias]
Parameter [Style] set to [Scientific (Color Constancy)]
Parameter [LRGB Method Emulation] set to [Straight CIELab Luminance Retention]
Parameter [Dark Saturation] set to [2.00]
Parameter [Bright Saturation] set to [Full]
Parameter [Saturation Amount] set to [200 %]
Parameter [Blue Bias Reduce] set to [1.00]
Parameter [Green Bias Reduce] set to [1.19]
Parameter [Red Bias Reduce] set to [1.44]
Parameter [Mask Fuzz] set to [1.0 pixels]
--- Wavelet De-Noise
Parameter [Scale 1] set to [90 %]
Parameter [Scale 2] set to [90 %]
Parameter [Scale 3] set to [90 %]
Parameter [Scale 4] set to [90 %]
Parameter [Scale 5] set to [65 %]
Parameter [Mask Fuzz] set to [1.0 pixels]
Parameter [Scale Correlation] set to [3]
Parameter [Color Detail Loss] set to [12 %]
Parameter [Brightness Detail Loss] set to [12 %]
Parameter [Grain Size] set to [4.5 pixels]
Parameter [Read Noise Compensation] set to [Off]
Parameter [Smoothness] set to [75 %]
File saved [F:\Astro\work\M33-LRGB_ST.tiff].



Thanks,
Prabhakar

[admin]

Thanks Prabhakar, that's very helpful!
I can see you don't do a re-stretch of your data after applying Wipe. In most cases Wipe will have freed up dynamic range that was formerly allocated to gradients and/or color bias. Redoing you stretch will help make the most of the newly available dynamic range - it is highly recommended and is most likely the cause of the 'clipped' appearance (even though the data has not been clipped but merely 'compressed' into level 0 of an 8-bit histogram).

[prabhakar]

Thanks for this information, Ivo.
I will re-process as per your suggestion.