Author Topic: Sh2-174 - HaOIIIRGB - Valentine Rose  (Read 192 times)

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Roberto

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Sh2-174 - HaOIIIRGB - Valentine Rose
« on: Sep 27, 2020, 17:45:16 »
Another lovely Sharpless object; this is the the northernmost in the catalog.

Very difficult one to image - very faint! Had some very good seeing but also very hazy skies for over half of the acquisition time so dealing with gradients was a chore.

Full resolution, bicolour, RGB and annotated versions here:

https://www.astrobin.com/ypasor/H/?nc=user

A is OIII, B is Ha, C is BiColour using the dynamic narrowband tutorial on https://thecoldestnights.com/

Roberto


Carole

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Re: Sh2-174 - HaOIIIRGB - Valentine Rose
« Reply #1 on: Sep 28, 2020, 12:00:26 »
I have never tried this, I suspected it was faint, and small?

You have captured a very nice image Roberto.

Carole

Roberto

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Re: Sh2-174 - HaOIIIRGB - Valentine Rose
« Reply #2 on: Sep 28, 2020, 14:02:59 »
Hi Carole

Thank you.  It is rather faint but responds equally well in Ha and OIII so that you can create a bicolour image of it.  My FOV is almost 2 degrees a side so not that small.

It's interesting that the parent star of the planetary nebula, white dwarf GD561, which is the very blue star in between the Ha and OIII regions seems to be running away from the shell of dust it created:  http://adsabs.harvard.edu/full/1994AJ....108..978T

Roberto

Mac

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Re: Sh2-174 - HaOIIIRGB - Valentine Rose
« Reply #3 on: Sep 28, 2020, 15:38:58 »
Nice Image,



I dont think i've ever seen this one.

it will be nice to add the blue component, especially as the green and red are pretty good themselves.

Mac.
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NoelC

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Re: Sh2-174 - HaOIIIRGB - Valentine Rose
« Reply #4 on: Sep 29, 2020, 09:52:33 »
Roberto
Fascinating; certainly a challenge.

Very nicely processed.

Noel
Synta mount, a bunch of telescopes and a shed (on wheels).

Roberto

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Re: Sh2-174 - HaOIIIRGB - Valentine Rose
« Reply #5 on: Sep 29, 2020, 13:30:46 »
Thank you Mac, Noel.

Mac, this is a bicolour narrowband image with RGB stars.  I don't actually know if the planetary emits any SII (I doubt it).  The actual mapping of colours for the nebula was:

R = Ha
G = ((OIII*Ha)^~(OIII*Ha))*Ha + ~((OIII*Ha)^~(OIII*Ha))*OIII
B = OIII

The expression ~ in PixInsight means (1-Channel ADU), i.e. the inverse, as images are normalised to 1.

Roberto