Getting plate-solving status, please wait...
Shelob's Lair (Mark 3), 



    
        

            Paul Hancock

Shelob's Lair (Mark 3)

Getting plate-solving status, please wait...
Shelob's Lair (Mark 3), 



    
        

            Paul Hancock

Shelob's Lair (Mark 3)

Imaging telescopes or lenses: William Optics Star 71 II WO Star 71

Imaging cameras: ZWO 183MM PRO

Mounts: iOptron CEM40

Guiding telescopes or lenses: William Optics Star 71 II WO Star 71

Guiding cameras: ZWO 290 Mini

Software: SGP  ·  Topaz denoise AI

Filters: ZWO OIII 7nm 1.25" ZWO OIII  ·  ZWO SII 7nm 1.25" ZWO SII  ·  ZWO Ha 7nm 1.25" ZWO Ha


Dates:Oct. 11, 2020

Frames:
ZWO Ha 7nm 1.25" ZWO Ha: 150x300" (12h 30') (gain: 111.00) -15C bin 1x1
ZWO OIII 7nm 1.25" ZWO OIII: 51x300" (4h 15') (gain: 111.00) -15C bin 1x1
ZWO SII 7nm 1.25" ZWO SII: 32x300" (2h 40') (gain: 111.00) -15C bin 1x1

Integration: 19h 25'

Darks: ~40

Flats: ~20

Flat darks: ~20

Avg. Moon age: 23.62 days

Avg. Moon phase: 34.62%


Basic astrometry details

Astrometry.net job: 3985536


Resolution: 3631x2286

Data source: Backyard

Description

Shelob lies in wait, anticipating the harmonious twang as her next meal becomes entrapped in her web. You can see the remains of a small scorpion to her left, a previous meal.

The Tarantula nebula is a massive HII region within the Large Magellanic Cloud. The weather was briefly good here and the seeing was exceptional. This is 6 hours of SHO data captured from my backyard. Hopefully the weather will clear again so I can continue to capture photons of this beautiful region of space.

I am still playing around with the framing on this one and finding my own way of applying Eric Coles tone mapping techniques. I also decided to use all of the Ha data as luminance rather than being overly selective, the moderate loss in sharpness is more than made up for in my eyes by the drastic reduction in background noise.

I am still hoping to capture much more OIII and SII data in the coming months, as the Ha stack looks good now.

Let me know if you think I'm barking up the wrong tree in terms of my luminance and colour palette as compared to Mark 2.

Comments

Revisions

    Shelob's Lair (Mark 3), 



    
        

            Paul Hancock
    Original
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            Paul Hancock
    B
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    C
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            Paul Hancock
    D
    Shelob's Lair (Mark 3), 



    
        

            Paul Hancock
    G
    Shelob's Lair (Mark 3), 



    
        

            Paul Hancock
    I
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    J
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  • Final
    Shelob's Lair (Mark 3), 



    
        

            Paul Hancock
    L

B

Description: Whoops, uploaded an earlier version before final tweaking.

Uploaded: ...

C

Description: Bye Bye neon purple and blue.

Uploaded: ...

D

Description: Manged to use a range mask to take the more colourful sho image and add in the more duotone tarantula. The best of both worlds now.

Uploaded: ...

G

Description: Another reframing. I think this one is my favourite so far. Shelob take up the bottom right of frame along with all the previous meals and detritus ensnared in her web. Which contrasts with the blackness and emptiness of space that takes up the remainder of the frame. Of note, the stars within Shelob's web are colourful, while the stars within the blackness of space are fairly monotone

Uploaded: ...

I

Description: Same as G, I forgot to add the luminance! Thought it looked a bit soft.

Uploaded: ...

J

Description: Same as I but tighter framing, still playing with it. I do like the fairly monochrome empty space, I feel it adds to the story.

Uploaded: ...

K

Description: Went back and reprocessed the HA luminance again to tone it down and try and reduce noise even further.

Uploaded: ...

L

Description: This is version 8 now, another complete reprocess. I took the very best Ha frames and gave them a very mild stretch before removing the stars. This starless image was taken into topaz denoise and I spent a very long time playing with the settings. I decided only to denoise using the lowlight setting and did not apply any sharpening, in fact I used the recover original detail slider as I felt even at a noise reduction of only 2 it was still too much. The recover original detail slider works like an opacity layer in PS, it blends in the noise reduced version with the original. I then returned the image to PI, did a HDRmultiscale transform and then added the stars back. For the colour I simply used the previous version, used MLT with all layers off except the residual and then again took that into topaz denoise and hit it hard with noise reduction and no sharpening. Finally I used the Ha layer as a luminance for the blurred and denoised colour data and reduced the stars using the Adam Block de-emphasis technique.

Uploaded: ...

Sky plot

Sky plot

Histogram

Shelob's Lair (Mark 3), 



    
        

            Paul Hancock