Strottner-Drechsler 17 (more widely known as Sharpless 2-123) is a planetary nebula that was previously thought to be an HII region. It was only this past January that spectroscopy confirmed that StDr 17 / Sh 2-123 was indeed a planetary nebula. If your French is good, check out
Andreas Bringmann's image, which contains the spectroscopic confirmation write-up. If your French isn't great, the key part by Quentin Parker is in English and it reads:
"An HII region ID is ruled out by the very high [NII] to H-alpha ratio in the spectra despite the fact it is among areas of extended nebulosity. The nature of this object (and colours) are distinct. I think it is a highly evolved bipolar PN with a likely high mass progenitor of Type I chemistry."This one is fainter than I was expecting. It was also the first time I've ever added data and not been able to see any difference from my previous test stack - I originally planned on getting 25 hours of hydrogen, but my last 3.5 hours did nothing to improve the SNR (at least that I could see).
I want to dedicate this one to
Goofi, whose
image of this target - the first one on Astrobin - inspired me to do it years ago. It took me way too long to get around to this target and I always planned on writing to him to ask him for some pointers before I started shooting it, but unfortunately we lost him before I got around to it. I'm bummed I never got a chance to talk with him, but even without personal contact, he definitely made his mark on me and the astro community as a whole (especially over on
Cloudy Nights).
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