Astronomy Picture of the Day: 22/01/2026
- lizarmarego
- Jan 22
- 2 min read
Object Name: Sharpless2-34
Copyright: Narayan Mukkavilli
Location: North West, NSW
Skill level: Professional (10+ years)
Image Title
Sh2-34 in HaRGB
Artists' statement
aka Gum 77a/ RCW 149/ LBN 38, this large HII region is close to the Lagoon and Triffid nebulae and consequently seems to be often overlooked by imager. I find this amongst the finest of the objects on the Sharpless 2 catalogue. It would, I think benefit from the addition of OIII data, something to attempt at some future point in time. For now this is a HaRGB image from a Bortle 7.6 location.
How This Image Was Captured
Gear used
Sharpstar Z4/ ZWO 533 MM and 533MC/ Antlia 3 nm Ha filter/ Antlia Triband filter/ EQ6
Exposure details
5 hours in Ha ; 1 hour and 15 minutes in RGB
Processing notes
Stacked in AstroPixelPricessor; processed in Pixinsight
Exploring Sharpless 2-34
This object is a large but faint emission nebula. It is a region of sky mainly of ionized hydrogen gas, located in the constellation Sagittarius, within a dense star field of the Milky Way. This nebula is often referred to as 'the forgotten nebula', it has a very low surface brightness, which makes it far less appealing compared to the surrounding nebulae such as the Triffid. Sharpless 2-34 lies roughly 4,500 light-years away from Earth. Sh2-34 is energized by young, hot stars whose radiation causes the surrounding gas to glow, indicating ongoing or recent star-forming activity. Because it is so diffuse and extended, it is extremely difficult to observe visually, but it becomes much more striking in long-exposure, wide-field astrophotography, especially when imaged through narrowband filters such as H-alpha that highlight its delicate filaments and subtle structure.
Behind the Selection
This image receals a part of our universe that is normally invisible to the human eye. This image has remarkable dynamic structure. The sweeping filaments, folds and cavities hidden in the gas show how stellar wind and solar radiation sculpt gas clouds over millions of years. Dark lanes and knots embedded in the glow are cold dust clouds, dense enough to block background starlight, and these are often the very places where new stars are still forming. The contrast between glowing gas and dark dust gives the scene depth and a three-dimensional, almost turbulent appearance, emphasizing that this is not a static cloud but a constantly evolving environment.
The sheer scale and detail make it extraordinary. Capturing both the faint, diffuse nebula and the pinpoint stars in a single frame requires exceptional technical skill, careful calibration, and hours of exposure time. The result is not just a beautiful picture, but a scientifically meaningful portrait of how galaxies recycle gas into new generations of stars—making the image both visually stunning and deeply informative.
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