Sh2-174 / PK 120+18.1 – Valentine's Rose

[Herbert West]

Due to very unfavorable weather in Poland during this winter and early spring, gathering enough light for a satisfying image of this relatively dim object took a long time indeed.

I'd chosen this Sharpless object not on its own merits, but because my primary targets for 2023 are still too low. Sh2-174 was one of the very few PNs suitable for HOO image available, so I took it without much enthusiasm.

It turns out I should've been enthusiastic because it's a fascinating and beautiful nebula. That is, if one's willing to put in enough hours imaging it.

Main image:

Starless:

Ha:

OIII:

 

Time & Place:

Holy Cross mountains, Poland, Bortle 4, 08.02.2023 - 23.04.2023.

 

 Exposures:

1. Ha- 233 x 300 s = 19,46 h.

2. OIII- 207 x 300 s = 17,25 h.

3. RGB – 30 x 60 s per channel.

Sum: 38,21 g.

 

Gubbins:

Telescope: SkyWatcher Maksutov-Newtonian MN190, 190/1000 mm

Camera: ASI1600MMP,

Filters: Antlia Ha 3nm, Antlia OIII 3nm,

Mount: SkyWatcher EQ6PRO

Guider: SvBony 240mm, ASI120MM mini,

Accessories: ZWO EFW, ZWO EAF, ASIAir V1

 

Workflow

A. Pixinsight,

1. DynamicCrop,

2. BlurXterminator (next to useless here, no high-frequency details),

3. StarXterminator,

4. DynamicBackgroundExtraction,

5. NoiseXterminator,

6. GeneralizedHyperbolicStretch in many incremental iterations, with noise reduction along the way.

B. Photoshop

1. Gradient Map on Ha i OIII,

2.  Levels on both channels,

3. Export to Pix, slight HDRMultiscaleTransform

4. A bit of Gaussian Blur,

5. Local Contrast Enhancement from Astronomy Tools,

6. Major resamples

7. Delicate noise reduction with TopazDenoise, with masks, no sharpening,

8. Hue/Saturation tweaks,

9. RGB stars via Screen.

 

Clear skies!

[Mandy D]

@Herbert West It certainly is beautiful. I love the colours that you have brought out in it, especially the purple. You don't see enough deep puple in nebula photos. I prefer the first image with the stars, it makes it look as though the nebula is floating through them. You also have some lovely detail in the first mono image, nice and clear. Excellent job.

[Herbert West]

Thanks Mandy. I'm partial to pink, purple and some magenta in my HOO images, however far from natural Ha and OIII colors they may be.