The RCW 120 Emission Nebula

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Russ.Carpenter
Posts: 159
Joined: Thu Jul 17, 2014 8:20 pm
Location: Green Valley, Arizona

The RCW 120 Emission Nebula

Post by Russ.Carpenter »

The last time I posted to this forum was March, 2016. At that time I decided I needed to buckle down and learn PixInsight, just to communicate with my fellow astro imagers here in Southern Arizona. After having spent the next years mastering PI (more or less), I was delighted to discover that StarTools has progressed a lot. Version 1.7 has many wonderful features and I’m looking forward to diving in.

These days I’m using the four telescopes at Chilescope in the Atacama desert. The equipment and location are nearly ideal, but the cost of remote telescopes depends on total exposure time. Many of us try to keep total time to a reasonable level. My projects usually require about 2.5 hours of total imaging time.

I often hunt for the rare stuff. It’s not uncommon to be the first, second or third amateur to image a deep space object. RCW 120 is a good example. I’ve found only one other image of RCW 120 published by an amateur.

The image uses the Ha and OIII channels and total imaging time was 2.7 hours. The processing was done on an iMac (I’m grateful that Ivo has continued to support Macs.) Here are the specs for the telescope used in this project. This is the link to Astrobin: https://www.astrobin.com/kd3leu/?nc=user

Tech Notes for ASA 500/3.6:
ASA Newtonian, 500 mm aperture, 1900mm focal length, F3.6
FLI Proline 16803, 9 mm pixel, 4096 X 4096
ASA DDM85 equatorial mount
Processing with PixInsight and StarTools

Russ
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admin
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Re: The RCW 120 Emission Nebula

Post by admin »

That's a great image of a rarely imaged (and very interesting!) object indeed - thank you very much for sharing!

How were the channels mapped (did you use the Compose module for this?). Was there much interesting signal in the O-III stack? If there is indeed detail, then by creating a, say, HOO bi-color using the Compose module, you can balance Ha and O-III coloring (and thus their visible dominance) with impunity without introducing more luminance noise. You can even remap/reweigh your channels on-the-fly in the Color module for some other interesting color rendition experimentation.
Ivo Jager
StarTools creator and astronomy enthusiast
Russ.Carpenter
Posts: 159
Joined: Thu Jul 17, 2014 8:20 pm
Location: Green Valley, Arizona

Re: The RCW 120 Emission Nebula

Post by Russ.Carpenter »

Hi Ivo,

It's a pleasure to be in touch with you again!

I did use the Compose module, initially mapping to HOO. There was just enough OIII to add some texture to the right side of the nebula. I didn't try rebalancing the channels in the Compose module, but I did experiment with remapping in the Color module. All-in-all, a brilliant approach to narrowband! From my point of view, narrowband presents the most interesting opportunities in astro processing these days and I look forward to becoming more adept with your innovative ideas.
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