Sh2-284 in Narrowband with RGB Stars

Mike Lewis

Staff Member
So I took a foray into 15 minute long subframes on this object, as the Oiii and especially the Sii signals were VERY weak. Even so I eventually decided on a red-blue look instead of the more conventional 3 channel SHO style image, although I did use all 3 narrowband datasets to make this. In addition, I also made a pseudo-luminance master by combining all 3 of the narrowband channels together and then combined that result with the color data. The central object is typically seen in images, but some of the surrounding nebulosity surprised me with its extent and detail.

Sh2-284 is an emission nebula region, often referred to as the 'Little Rosette' Nebula or the Portal Nebula. It is shaped by a young energetic star cluster Dolidze 25 which is sending out ionizing radiation to excite the nebula. Sh2-284 is believed to be approximately 15,000 light years distant in an outer spiral arm of the Milky Way, in the constellation Monoceros.

A larger version is also here on Astrobin:

https://app.astrobin.com/u/mlewis?i=5t40lv#fullscreen

As always comments, questions, and critiques all most welcome, and thanks for looking!

Sh2-284:

LRCC_sRGB_FW_Sh2-286_SA-PPP-R1_GHS_CT_LHE_Mix1_SynthLumBlend_DSE_PSCC_WithStars.jpg


Capture details follow.

Equipment:
QHY268M Camera @ -5C and
Gain:56 Offset:25
Software Bisque MyT Mount
Stellarvue SVQ100 Astrograph Refractor, 580mm @ f/5.8
Antlia Pro Filters (3nm narrowband plus LRGB)
QHY OAG-M/ASI290MM

Software:
Pixinsight Commercial Version 1.8
Lightroom CC
Photoshop CC
N.I.N.A. Control Software
BlurXTerminator (Russell Croman)
StarXTerminator (Russell Croman)
NoiseXTerminator (Russell Croman)

Light Frames:
Gain 56 / Offset 25
Hα: 25 x 900 secs (6 hrs 15 mins)
Oiii: 27 x 900 secs (6 hrs 45 mins)
Sii: 25 x 900 secs (6 hrs 15 mins)
Red: 22 x 30 secs (11 mins)
Green: 21 x 30 secs (10 mins 30 secs)
Blue: 21 x 30 secs (10 mins 30 secs)

19 hrs 47 mins total

Dark Frames:
10 x 30 secs (5 mins)
10 x 600 secs (1 hr 40 mins)
 

JimFox

Moderator
Staff member
Hey Mike, I am finally at my daughters and able to get on my computer to look at this.

I really love the look of this. That OIII showing through is always cool in an image in my book, and you have a really nice pocket of it here. So I like your work and how you got the extra detail out from it. A really awesome job.
 

Mike Lewis

Staff Member
Hey Mike, I am finally at my daughters and able to get on my computer to look at this.

I really love the look of this. That OIII showing through is always cool in an image in my book, and you have a really nice pocket of it here. So I like your work and how you got the extra detail out from it. A really awesome job.
Thanks Jim! As always, a bit hard to see what you might be getting when you start, but I was definitely pleasantly surprised at the way the weaker Oiii was able to come out with some stretching.
 
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