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Sh2-101 "Tulip" Nebula in Cygnus, 





    
        

            Daniel.P
Sh2-101 "Tulip" Nebula in Cygnus

Sh2-101 "Tulip" Nebula in Cygnus

Acquisition type: Electronically-Assisted Astronomy (EAA)

Technical card

Resolution: 4272x2860

Dates:July 19, 2019July 22, 2019

Frames:
AstroDon 5nm Ha filter: 4x600" (gain: 139.00) -12C bin 1x1
AstroDon 5nm Ha filter: 9x600" (gain: 139.00) -9C bin 1x1
AstroDon 5nm OIII filter: 4x600" (gain: 139.00) -12C bin 1x1
AstroDon 5nm OIII filter: 9x600" (gain: 139.00) -9C bin 1x1
AstroDon 5nm SII filter: 4x600" (gain: 139.00) -12C bin 1x1
AstroDon 5nm SII filter: 7x600" (gain: 139.00) -9C bin 1x1
ZWO new B: 5x120" (gain: 139.00) -9C bin 1x1
ZWO new G: 5x120" (gain: 139.00) -9C bin 1x1
ZWO new L: 10x60" (gain: 139.00) -12C bin 1x1
ZWO new R: 5x120" (gain: 139.00) -9C bin 1x1

Integration: 6.8 hours

Avg. Moon age: 18.49 days

Avg. Moon phase: 83.71%

Mean SQM: 21.20

Mean FWHM: 3.00

Astrometry.net job: 2883292

RA center: 300.014 degrees

DEC center: 35.347 degrees

Pixel scale: 0.910 arcsec/pixel

Orientation: 0.124 degrees

Field radius: 0.650 degrees

Locations: Duc, Prayssas, Lot et Garonne, France

Data source: Backyard

Description

This is the first target of this 2019 summer session.
The ASI1600 could not be cooled below -12°C/-9°C due to very hot temperature.
The main effect was more dark noise (RON 1.6e as usual, Dark Noise 2.9e (10min@-9°C) versus (1.8e /10min@-18°C)) and bad seeing (3").
The Ha photon shot noise was 2.1e for 10mn exposure.
I have computed that the penalty for poor cooling (-9 vs-18) is +30% exposure time needed for this NB imaging.

The second version is with eroded stars ...

During the night of the 22nd of July, I left my equipment FULLY UNATTENDED during the full night.
It performed its first "UNATTENDED" Meridian Flip just after 02h00 during Ha exposures. I wake up late in the morning, the telescop was parked and the camera warmed up.

So far I have not used the L, R,G & B exposures ...

The processing was done in PI as follow :
For each S, H, O channels :
- Images Calibration (Dark Substraction)
- Cosmetic Correction
- Image Registration
- Image Integration
- CROP to remove the image rotation between the two days
- Mure Denoise
Then :
- Creating Super Lum channel by adding SHO channels weighted by PI Integration process
- Deconvolution masked with 2.0 pixel psf of the Super Lum
- LRGB combination using SuperL, H,S & O channels
- Color balance and Color saturation on stars
- Going NL using Masked Streched
- SCNR
- Color Saturation masked using stars (and desaturate bkg)
- Redo Color Balance on stars
- Local Histogram Equalisation masked (slight)
- TGV denoise masked

Final image adjustments performed in Iphoto on Imac :
- levels adjustments
- color sat
- use "selective color" to remove purple in some stars, and enhance blue
- deflip

Comments

Author

Daniel.P
Daniel.P
License: None (All rights reserved)
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Revisions

  • Final
    Sh2-101 "Tulip" Nebula in Cygnus, 





    
        

            Daniel.P
    Original
  • Sh2-101 "Tulip" Nebula in Cygnus, 





    
        

            Daniel.P
    C

C

"Eroded" stars

Sky plot

Sky plot

Histogram

Sh2-101 "Tulip" Nebula in Cygnus, 





    
        

            Daniel.P