Celestial hemisphere:  Northern  ·  Constellation: Cepheus (Cep)  ·  Contains:  Sh2-136  ·  VdB141
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Ghost Nebula Sh2-136, Anthony Quintile
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Ghost Nebula Sh2-136

Getting plate-solving status, please wait...
Ghost Nebula Sh2-136, Anthony Quintile
Powered byPixInsight

Ghost Nebula Sh2-136

Equipment

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Acquisition details

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Description

This is my second image with my new C9.25, and my first with the new Starizona SCT Corrector IV, and the first with stacking in PI since starting Adam Block's Fundamentals tutorials.

This image represents the culmination of learning and/or troubleshooting several things.

I realized that my ASI2600MC Pro was vibrating because of the fan, (resolved with a Fractal fan), which was apparent when shooting with the SCT.

The Starizona SCT Corrector IV resolves some chromatic aberration issues since it is made with ED glass, unlike earlier iterations. I struggled especially with star color with all of my SCT images until now. I cannot recommend this corrector highly enough! Get this if you have an SCT!

I am plugging through Adam Block's Fundamentals Pixinsight training. This image was stacked using the NSG Script (and other advice from Adam's training). The NSG script seems to resolve several questions I have been mulling about how to weight or cull data shot when there are high, thin clouds or thin wildfire smoke in the upper atmosphere, as well as mitigating gradients. This is done "at the source" during stacking, which seems pretty smart. Check out the  NSG Script, and if you are wanting to learn PI the right way, not only what those settings do but why, I highly recommend Adam's course. Be prepared to spend some time, as I have spent several hours with the courses, and I feel like I am only skimming the surface of his offerings, but highly worth it.

As with all of my images, I feel like I could do better with more knowledge on processing. The more I know, the worse this feeling gets. This is a personal issue.

Comments

Revisions

    Ghost Nebula Sh2-136, Anthony Quintile
    Original
    Ghost Nebula Sh2-136, Anthony Quintile
    B
    Ghost Nebula Sh2-136, Anthony Quintile
    C
  • Final
    Ghost Nebula Sh2-136, Anthony Quintile
    D

B

Description: I had over reduced the star brightness which led to the stars having weird artifacts.

I corrected that.

Uploaded: ...

C

Title: Complete reprocess from previous WBPP/NSG integration

Description: The original of this image was shot before I got the backspacing and collimation of my newer C9.25 with Starizona SCT Corrector IV dialed in. It suffered from some substantial coma in the corners because of this.

Additionally, I was very early on in my use of Pixinsight for processing, so very little of the processing was done in Pixinsight.

This new processing is entirely in Pixinsight.

A few notable things:

Although there was a some coma in the corners, at least partially because of back-focus and/or sensor tilt issues, the Starizona SCT Corrector IV does not suffer from the significant chromatic issues that the SCT Corrector II that I used previously did. I have noticed that the SCT data generally seems to result in some purpleish fringing on some stars. I have addressed this with targeted de-saturation using the Color Saturation process. Using this tool can be sort of like mixing out noise or other bandwidths in sound/music recording, with which I have very limited, but some, experience.

This image benefitted dramatically from using Russell Croman's BlurXTerminator. It did a phenomenal job with the coma-ed stars almost out to the far corners of my APS-C sensor. A few stars at the extreme outside on one side of the image (probably some sensor tilt?), did suffer from a doubling effect after applying BlurX, but this was easily remedied with a few minutes of Clone Stamping.

I have really been getting some practice with generating masks in various ways. For example, by using extracted Luminance and Histogram Transformation/Binarization/Convolution I made various masks to help target NoiseX noise reductions while retaining the faint wispiness in the brighter nebula.

The diffraction spikes on the stars on the left are from my slightly-too-low off axis guider mirror. I think I have that remedied now.

Uploaded: ...

D

Description: In my efforts to reduce some purple color fringing around some stars using the Color Saturation tool, I created some crispiness around some other stars that I hadn't noticed at first.

Additionally, I felt like I had over-reduced the stars generally.

This revision has a gentler application of the Color Saturation (reduction) tool applied on the un-screened stars to reduce the purple halos, (rather than after re-screening into the starless image), and slightly brighter stars.

Uploaded: ...

Sky plot

Sky plot

Histogram

Ghost Nebula Sh2-136, Anthony Quintile