Starship Asterisk*

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The Whirlpool Galaxy (Messier 51) has been a popular night sky target for astronomers for centuries. Charles Messier first identified it in 1773 and listed it as number 51 in his catalog. To him, it looked like a faint, fuzzy object that might be a comet. William Parsons, the 3rd Earl of Rosse, used his 72-inch telescope “Leviathan” to observe the Whirlpool in 1845. Since then, Messier 51 has likely been targeted by virtually every telescope in the northern hemisphere. It is found in the constellation Canes Venatici (the Hunting Dogs) and is a classic example of a spiral galaxy.

Now, a new camera on the WIYN 3.5-meter telescope at Kitt Peak National Observatory has imaged the Whirlpool Galaxy anew. The wide field of the One Degree Imager (ODI) camera makes it possible to capture the entire galaxy and its companion in one pointing, something that even the Hubble Space Telescope cannot do.
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The WIYN ODI camera spent about an hour observing M51 through three different filters: blue, green, and red. These digital images were later combined to construct a “true-color” image: redder objects in the image are cooler, emitting most of their light at longer optical wavelengths, while bluer objects in the image are bluer and hotter in reality. Objects that glow green are somewhere in between. Even though the galaxy is almost 30 million light years away, the image clearly shows clusters of young, hot stars that light up the spiral arms. Threaded through the arms are dark “dust lanes”, where sooty material left over from previous generations of stars has settled. More dust lanes can be seen in the bridge of luminous stars and gas that connects Messier 51 to its companion, the peculiar galaxy NGC 5195, in the upper part of the image. ...

Pushing back the frontiers of the unknown. On the left: destinations in the Solar System as seen by historic robotic spacecraft and telescopes. On the right: the same worlds as seen by recent missions that have filled in some of the blank spaces on the map.

Original images by NASA / JPL / SSI / JHUAPL / STScI / SwRI / GSFC / ASU / MSSS / MAIIGAiK
Processing by Val Klavans / Montage by Bill Dunford