Eta Carinae: Mucking about with someone else’s data

With the long evenings precluding any weekday astro activity at the moment I decided to get a fix from Pete Williamson’s data that Andy provided for RAG members on this blog.

I didn’t want to get data for something that I could image myself so I went for Eta Carinae Nebula, which is a Southern Hemisphere object. You can read more about it here, but in summary it’s a very large and bright nebula (4 times the size of Orion, although further away) and after spending a bit of time playing with it on a computer I’d love to point a telescope at it.

The data is, as you would expect from top end gear working in a complete absence of light pollution, terrific. It comes pre-calibrated (although the SHO image below had a few hot pixels appearing in it), and both the images below had 3x 5 minute subs for each channel (so the HaRGB is an hours data, whilst the SHO is 45 minutes). I’ve never managed to get my head around pre-processing on Pixinsight so I used DSS to stack each channel then registered and merged them in Pixinsight using Pixelmath. I was able to drop background extraction (which tackles light pollution and other issues) and noise reduction from my usual workflow, and used only a tiny bit of sharpening.

I’m more taken with this approach than I expected: it doesn’t bring the same feeling of achievement that creating your own image does, but it was great to be able to explore such a large and beautiful object that you can’t see from this side of the planet and I love the finished product. It also gave me a chance to work with mono data for the first time and learn how to create an image in the SHO palette as per Hubble. In summary, I’d rather work with my own data, but this was a fun thing to do and I’ll certainly look forward to finding another Southern Skies object to explore in this way.

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