Updated: IC5146 The Cocoon Nebula in Cygnus, 2019-07-05 (Different Framing)

[The Thing]

Colour balance hopefully less blue. Seems to have improved the star colours as well.
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Much much nicer image. No StarTools involved, no calibration either. No cropping or binning.
1h31m 22 x 250s, Gain 121, Offset 4, Temp-15C

Image date, time and location:         2019-07-05 Manche, France
Telescope aperture and focal ratio:    TS1506UNC f4, TS Komakorr
Camera and filters used:                  ZWO ASI294MC Pro, Baader Neodymnium 1.25" filter
Processing applied:                          DSS 4.2.0 Beta5 (all settings below), DarkTable

Code Select Expand


DSS-> Autosave

Stacking mode: Standard
Alignment method: Automatic
Stacking step 1 ->22 frames (ISO: -) - total exposure: 1 hr 31 mn 40 s
RGB Channels Background Calibration: No
Per Channel Background Calibration: No
Method: Kappa-Sigma (Kappa = 1.65, Iterations = 2)
-> No Offset -> No Dark -> No Flat
=======================
FitsDDP|BayerPattern=4
FitsDDP|BlueScale=1.0000
FitsDDP|Brighness=1.0000
FitsDDP|DSLR=Generic RGGB
FitsDDP|FITSisRAW=1
FitsDDP|ForceUnsigned=0
FitsDDP|Interpolation=AHD
FitsDDP|RedScale=1.0000
RawDDP|AHD=0
RawDDP|AutoWB=0
RawDDP|BlackPointTo0=1
RawDDP|BlueScale=1.0000
RawDDP|Brighness=1.0000
RawDDP|CameraWB=0
RawDDP|Interpolation=Bilinear
RawDDP|RawBayer=0
RawDDP|RedScale=1.0000
RawDDP|SuperPixels=0
Register|ApplyMedianFilter=1
Register|DetectHotPixels=1
Register|DetectionThreshold=84
Register|PercentStack=100
Register|StackAfter=1
Stacking|AlignChannels=1
Stacking|AlignmentTransformation=0
Stacking|ApplyFilterToCometImages=1
Stacking|BackgroundCalibration=0
Stacking|BackgroundCalibrationInterpolation=1
Stacking|BadLinesDetection=0
Stacking|CometStackingMode=2
Stacking|CreateIntermediates=0
Stacking|DarkFactor=1.0000
Stacking|DarkOptimization=0
Stacking|Dark_Iteration=1
Stacking|Dark_Kappa=1.5000
Stacking|Dark_Method=2
Stacking|Debloom=0
Stacking|Flat_Iteration=1
Stacking|Flat_Kappa=1.5000
Stacking|Flat_Method=2
Stacking|HotPixelsDetection=0
Stacking|IntermediateFileFormat=2
Stacking|Light_Iteration=2
Stacking|Light_Kappa=1.6500
Stacking|Light_Method=4
Stacking|LockCorners=1
Stacking|Mosaic=0
Stacking|Offset_Iteration=1
Stacking|Offset_Kappa=1.5000
Stacking|Offset_Method=2
Stacking|PCS_ColdDetection=759
Stacking|PCS_ColdFilter=2
Stacking|PCS_DetectCleanCold=0
Stacking|PCS_DetectCleanHot=0
Stacking|PCS_HotDetection=759
Stacking|PCS_HotFilter=2
Stacking|PCS_ReplaceMethod=1
Stacking|PCS_SaveDeltaImage=0
Stacking|PerChannelBackgroundCalibration=0
Stacking|PixelSizeMultiplier=1
Stacking|RGBBackgroundCalibrationMethod=1
Stacking|SaveCalibrated=0
Stacking|SaveCalibratedDebayered=0
Stacking|SaveCometImages=0
Stacking|UseDarkFactor=0



[Carole]

Much better Duncan, so do you think Star tools is messing the image up?

No hang on a bit, it wasn't the Cocoon I had commented on it was the Swan.

Carole

[ApophisAstros]

no calibration either.

Does that mean you used no Darks as i have to do them because i get Amp glow on my Sony CMOS chip  at more than 60s or so.
I don't know how Sony get away with that as its on all of their chips apparently.
Just spotted Dark table is that how you remove Amp Glow?
Roger

[The Thing]

No, I didn't use darks for this, doesn't seem to make much difference to the result. I dither by two pixels each frame to get rid of pattern and hot pixel noise and cool to -15c.

I am finding that sometimes the amp glow shows and sometimes not. I suppose it depends on the amount of stretching. I tend to clone it out carefully. I did try Wipe in StarTools (mask the amp glow and hit the button) which works well. StarTools stretch really bring out the glow if your not careful.

[The Thing]

Carole, its very easy to mess up images with StarTools because it's so easy to push sliders too far and too use inappropriate processes!

[ApophisAstros]

No, I didn't use darks for this, doesn't seem to make much difference to the result. I dither by two pixels each frame to get rid of pattern and hot pixel noise and cool to -15c.

I am finding that sometimes the amp glow shows and sometimes not. I suppose it depends on the amount of stretching. I tend to clone it out carefully. I did try Wipe in StarTools (mask the amp glow and hit the button) which works well. StarTools stretch really bring out the glow if your not careful.

I image at -20 and dither but each lum and ha subs show Amp Glow after and darks are the only way to sort them with my Camera, over about a minute length,
Roger

[Carole]

Carole, its very easy to mess up images with StarTools because it's so easy to push sliders too far and too use inappropriate processes!

Oh dear, so it there not a way to stepping backwards if you mess it up or do you have to start all over again from the beginning?

Sounds to me like this software is best avoided.

Carole

[MarkS]

The reframing is much better.  However the image is now far too blue.  Look at the histogram of your data and you'll see what I mean.  The blue channel is completely detached from the red and green.  You need to look into your workflow to determine the cause.

Mark

[ApophisAstros]

Is it me or are your stars trailing in the corners? Could it be collimation.
Roger

[The Thing]

Thanks Mark. I'll have a look at the histogram again. I did post-processing in DarkTable (new to me and quite powerful) and the histogram looked OK - but I then went and disabled a few modules to see what was causing a lot of blurring and probably forgot to re-enable the colour correction. Duh.

Hi Roger, its more a corrector spacing issue coupled with focuser droop. I fixed the focuser yesterday and I think I need a 0.4 mm spacer in the T ring chain.

[The Thing]

I have updated the picture with a hopefully correct colour balance.