Celestial hemisphere:  Northern  ·  Constellation: Cepheus (Cep)  ·  Contains:  Sh2-136  ·  VdB141
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sh2-136 "Ghost Nebula" in Cepheus - LRGB, Daniel.P
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sh2-136 "Ghost Nebula" in Cepheus - LRGB

Acquisition type: Electronically-Assisted Astronomy (EAA, e.g. based on a live video feed)
Getting plate-solving status, please wait...
sh2-136 "Ghost Nebula" in Cepheus - LRGB, Daniel.P
Powered byPixInsight

sh2-136 "Ghost Nebula" in Cepheus - LRGB

Acquisition type: Electronically-Assisted Astronomy (EAA, e.g. based on a live video feed)

Equipment

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Acquisition details

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Description

I spent most of these 4 moonless nights with dark sky (around 21.3 SQM) to image this nebula with LRGB filters.

17 hours is currently my longest total exposure on a single target. Stars with mag 22.5 should be visible (with SNR=5) on the image.

My AO was off, and I use multistar guiding with PHD2 directly on the CEM120EC2 mount. It worked well but apparently, I was better not using to fast corrections (it seems to interfere with the encoders work). I used typically 2 sec guide steps. My objective is to use back AO with faster guide steps.

The image is color balanced on stars.

The processing was done in PI as follow :

For each L, R, G, B channels :

- Images Calibration (Dark Substraction, deFlat)

- Cosmetic Correction

- Image Registration

- Image Integration

- Mure Denoise

Then :

- Create super L image (integration of L and RGB individual channel)

- Create RGB image and color balance using R,G,B channels

- LRGB combination with superL

- DBE

- Color balance on stars

- Color Saturation masked (and desaturate bkg)

- Deconvolution masked with 1.8 pixel psf

- Background extraction

- Going NL using HT

- TGV denoise (no mask)

- Local Histogram Equalisation (at 90 pix scale)

- Color Saturation masked using stars to boost stars color

- Color Balance on stars

- Color Saturation masked using stars to boost stars color

- Deflip

- Crop

Final image adjustments performed in Iphoto on Imac :

- levels adjustments

Comments

Revisions

  • sh2-136 "Ghost Nebula" in Cepheus - LRGB, Daniel.P
    Original
  • sh2-136 "Ghost Nebula" in Cepheus - LRGB, Daniel.P
    C
  • Final
    sh2-136 "Ghost Nebula" in Cepheus - LRGB, Daniel.P
    D

C

Description: with star color deringing

Uploaded: ...

D

Title: Re Processed in 2024

Uploaded: ...

Sky plot

Sky plot

Histogram

sh2-136 "Ghost Nebula" in Cepheus - LRGB, Daniel.P