Camera Designed to Reveal the Deepest Secrets of Our Universe Captures the Southern Pinwheel Galaxy in Glorious Detail

Southern Pinwheel Galaxy, Messier 83

Nicknamed the Southern Pinwheel, Messier 83 (or NGC 5236) is a stunning face-on spiral galaxy located about 15 million light-years away in the southern constellation of Hydra. Its spiral arms are lined with dark lanes of dust and peppered with reddish, star-forming clouds of hydrogen gas. One of the deepest images ever taken of the Southern Pinwheel (combining more than 11 hours of exposure time), this view was captured with the Dark Energy Camera (DECam), which was built by the US Department of Energy (DOE) and is mounted on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab. Numerous background galaxies, which lie much farther away than Messier 83, appear around the edges of the image.
Credit: CTIO/NOIRLab/DOE/NSF/AURA, Acknowledgment: M. Soraisam (University of Illinois), Image processing: Travis Rector (University of Alaska Anchorage), Mahdi Zamani & Davide de Martin

The Spiral of the Southern Pinwheel

The Dark Energy Camera (DECam), which was originally designed for the Dark Energy Survey, has captured one of the deepest images ever taken of Messier 83, a spiral galaxy playfully known as the Southern Pinwheel. Built by the US Department of Energy, DECam is mounted on the Víctor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab.

Astronomy enthusiasts might wonder why a camera called the Dark Energy Camera (DECam) would be used to image a single spiral galaxy. DECam has in fact already finished its main job, as the instrument was used to complete the Dark Energy Survey, which ran from 2013 to 2019. Like many people, rather than enjoying a quiet retirement, DECam is remaining occupied. Members of the astronomical community can apply for time to use it, and the data collected are processed and made publicly available[1], thanks to the Astro Data Archive at the Community Science and Data Center (CSDC) Program at NSF’s NOIRLab. DECam’s continued operation also makes sumptuously detailed images like this one possible.

Messier 83, or the Southern Pinwheel, is located in the southern constellation of Hydra and is an obvious target for a beautiful astronomical image. It is oriented so that it is almost entirely face-on as seen from Earth, meaning that we can observe its spiral structure in fantastic detail. The galaxy lies around 15 million light-years away, which makes it a neighbor in astronomical terms. It has a diameter of around 50,000 light-years, so it is a little diminutive in comparison to our own Milky Way, which has a diameter of 100,000–200,000 light-years. In other ways, however, the Southern Pinwheel probably gives a good approximation of how our Milky Way would look to a distant alien civilization.

Six different filters were used on DECam in order to create this spectacular new view of a classical beauty. Filters allow astronomers to select which wavelengths of light they wish to view the sky in. This is crucial for science observations, when astronomers require very specific information about an object, but it also allows colorful images like this one to be created.

Observing celestial objects — such as the Southern Pinwheel — with several different filters means that different details can be picked out. For example, the dark tendrils curling through the galaxy are actually lanes of dust, blocking out light. In contrast, the clustered, bright red spots are caused by glowing, hot hydrogen gas (which identifies these as hubs of star formation). Dusty trails and dynamic ionized gas have different temperatures, and are therefore visible in different wavelengths. Filters allow both to be observed separately, and then combined into one intricate image. In all, 163 DECam exposures, with a total combined exposure time of over 11.3 hours, went into creating this portrait of Messier 83.

Yet these observations were not just about creating a pretty picture. They are helping to prepare for upcoming observations by Vera C. Rubin Observatory, a future program of NOIRLab. In ten years of operation, starting in 2023, Rubin Observatory will carry out an unprecedented optical survey of the visible sky named the Legacy Survey of Space and Time (LSST).

“The Messier 83 observations are part of an ongoing program to produce an atlas of time-varying phenomena in nearby southern galaxies in preparation for Rubin Observatory’s Legacy Survey of Space and Time,” said Monika Soraisam of the University of Illinois, who is the principal investigator for DECam’s observations of Messier 83. “We are generating multi-color light curves of stars in this galaxy, which will be used to tame the onslaught of alerts expected from LSST using state-of-the-art software infrastructure such as NOIRLab’s own ANTARES alert-broker.”[2]

Built by the US Department of Energy (DOE), DECam is mounted on the Víctor M. Blanco 4-meter Telescope at CTIO in Chile. DECam is a powerful instrument that uses 74 highly sensitive charge-coupled devices (CCDs) to take images. CCDs are the same devices that are used to take photos in everyday cell phones. Of course, the CCDs in DECam are much larger, and they were specifically designed to collect very faint red light from distant galaxies. This capability was crucial for DECam’s original purpose, the Dark Energy Survey.

This ambitious survey probed one of the most fundamental questions of the Universe — why is our Universe not only expanding, but expanding at an accelerating rate? For six years DECam surveyed the skies, imaging the most distant galaxies to collect more data to enable astronomers to further investigate our accelerating Universe. Taking beautiful images such as this one must seem a lot simpler for DECam.

“While DECam has fulfilled its original goal to complete the Dark Energy Survey, it continues to be a valuable resource for the astronomical community, capturing sweeping views of objects like Messier 83 that both delight the senses and advance our understanding of the Universe,” said Chris Davis, Program Director for NOIRLab at the National Science Foundation.


  1. Data from DECam typically have an 18-month proprietary period to allow the principal investigators who requested the observations time to perform their research before the data are released publicly for anyone to use. 
  2. ANTARES is a software tool built at NOIRLab to process information about changing objects in the night sky and to help distribute that information to the astronomical community.

5 Comments on "Camera Designed to Reveal the Deepest Secrets of Our Universe Captures the Southern Pinwheel Galaxy in Glorious Detail"

  1. BibhutibhusanPatel | February 18, 2021 at 11:53 pm | Reply

    Data collected to ĺocate the SouthernPinwheelGalaxy follow Space-TimeCurveture for measurement taken at two different time intervals.

    • Torbjörn Larsson | February 23, 2021 at 8:55 pm | Reply

      I’m not sure I follow.

      Yes, galaxies follow the general relativistic models of the universe with regards space curvature, and expansion behavior over time.

      No, a single galaxy observed at different times can’t generally probe that. (Though of it is active, say has an active galactic core of strong and changing emissions, some relativistic effects can be observed.)

  2. BibhutibhusanPatel | February 19, 2021 at 12:11 am | Reply

    The Galaxies follow the space-time curveture while observing the law of Hubble.As the SouthernPinwheelGalaxy can be found out as a result of some other galaxies measurement,the fact comply.

  3. Just read a story about blackholes from dark matter. (Nonsense) in the early universe I believe there were fewer blackholes and they were super giants. The mistake that keeps being made I believe is that all of this stuff in the uni happened all at once that’s absolute nonsense. There mite have only been a handful of blacksphere’s in the beginning and they were probably super giants made from super giant stars. As we can see the universe is like a clock and it’s winding down. Our part of the uni mite have come from a single star you have to remember How stuffed the universe was with gas and were not sure of the state of that gas. You say hot I say freezing I also believe that they could have been in a snow ball state because if that was the case your so called gravity wouldn’t have to exist for them to grow. Or for them to fuse the hydrogen they just have to keep growing and it would happen naturally as the snowball got to a point where the core would actually heat up and fuse the hydrogen. ( take that y’all ) that’s my theory. And once it starts it doesn’t stop till all the gases are gone. ( no big bang ) you all keep putting a time limit on everything you say that’s why your wrong. The universe could be trillions of years old it’s when matter first appeared that important for science. And that would also explain a lot more of the mysteries we call the universe. Sometimes you just have to say ok we’re wrong let’s start again.

  4. You see what we go from now is what we see but what we see isn’t what was it’s what’s now. Once the gas or hydrogen snow gets to a point where it starts the fusion process it’s never the same again. The state of the hydrogen would be changed forever and continues to change even today. Like I said before it’s like a clock and it’s been counting down ever since. I mite be wrong but I don’t think so. Think about what I said really give it a think. The gases we see today have been broken down so many times but it didn’t start like that it started in a snowy form I believe as their won’t be any form of heat in the beginning.

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