Photo of the Week

Saturn in the Milky Way

Image Credit & Copyright: Mohammad Nouroozi

Explanation: Saturn is near opposition in planet Earth’s sky. Rising at sunset and shining brightly throughout the night, it also lies near a line-of-sight to crowded starfields, nebulae, and obscuring dust clouds along the Milky Way. Whitish Saturn is up and left of center in this gorgeous central Milky Way skyscape, a two panel mosaic recorded earlier this month. You can find the bright planet above the bowl of the dusty Pipe nebula, and just beyond the end of a dark river to Antares, alpha star of the constellation Scorpius. For now the best views of the ringed giant planet are from the Saturn-orbiting Cassini spacecraft, though. Diving close, Cassini’s Grand Finale orbit number 8 is in progress.

Photo of the Week

Collapse in Hebes Chasma on Mars

Image Credit & Copyright: ESA/DLR/FU Berlin (G. Neukum)

Explanation: What’s happened in Hebes Chasma on Mars? Hebes Chasma is a depression just north of the enormous Valles Marineris canyon. Since the depression is unconnected to other surface features, it is unclear where the internal material went. Inside Hebes Chasma is Hebes Mensa, a 5 kilometer high mesa that appears to have undergone an unusual partial collapse — a collapse that might be providing clues. The featured image, taken by ESA’s robotic Mars Express spacecraft currently orbiting Mars, shows great details of the chasm and the unusual horseshoe shaped indentation in the central mesa. Material from the mesa appears to have flowed onto the floor of the chasm, while a possible dark layer appears to have pooled like ink on a downslope landing. A recent hypothesis holds that salty rock composes some lower layers in Hebes Chasma, with the salt dissolving in melted ice flows that drained through holes into an underground aquifer.

Photo of the Week


 Image Credit: ESO, VST/Omegacam Local Group Survey

Explanation: Named for the three astronomers instrumental in its discovery and identification, Wolf – Lundmark – Melotte (WLM) is a lonely dwarf galaxy. Seen toward the mostly southern constellation Cetus, about 3 million light-years from the Milky Way, it is one of the most remote members of our local galaxy group. In fact, it may never have interacted with any other local group galaxy. Still, telltale pinkish star forming regions and hot, young, bluish stars speckle the isolated island universe. Older, cool yellowish stars fade into the small galaxy’s halo, extending about 8,000 light-years across. This sharp portrait of WLM was captured by the 268-megapixel OmegaCAM widefield imager and survey telescope at ESO’s Paranal Observatory.

Photo of the Week

N159 in the Large Magellanic Cloud

Image Credit: NASA, ESA, Hubble Space Telescope

Explanation: Over 150 light-years across, this cosmic maelstrom of gas and dust is not too far away. It lies south of the Tarantula Nebula in our satellite galaxy the Large Magellanic Cloud a mere 180,000 light-years distant. Massive stars have formed within. Their energetic radiation and powerful stellar winds sculpt the gas and dust and power the glow of this HII region, entered into the Henize catalog of emission stars and nebulae in the Magellanic Clouds as N159. The bright, compact, butterfly-shaped nebula above and left of center likely contains massive stars in a very early stage of formation. Resolved for the first time in Hubble images, the compact blob of ionized gas has come to be known as the Papillon Nebula.

YAS Workshop

Astrophotography and the Yukon

An unforgettable experience awaits you as you capture the world famous Yukon Aurorae Borealis. Are you ready? (Photo by Thomas Jacquin) — in Whitehorse, Yukon Territory

Learn how to use your camera to take photos of the night sky!

When: 7 to 9 PM
Where: Yukon College, Room A2402
Suggested donation to the Yukon Astronomical Society: $5 per person
Covered topics will include:
  • Constellations
  • The moon
  • Planets
  • Northern Lights
  • and, much more…


Thomas Jacquin’s astrophotography has been published in:

Thomas Jacquin (YAS member) and his homemade 10″ Dobsonian telescope

Catheryne Lord has been an amateur photographer for 15 years:

  • Catheryne has studied Commercial photography at Dawson College in Montreal
  • Completing her Professional Photography Course with the New York Institute of Photography




Photo of the Week

Mimas in Saturnlight

Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explanation: Peering from the shadows, the Saturn-facing hemisphere of Mimas lies in near darkness alongside a dramatic sunlit crescent. The mosaic was captured near the Cassini spacecraft’s final close approach on January 30, 2017. Cassini’s camera was pointed in a nearly sunward direction only 45,000 kilometers from Mimas. The result is one of the highest resolution views of the icy, crater-pocked, 400 kilometer diameter moon. An enhanced version better reveals the Saturn-facing hemisphere of the synchronously rotating moon lit by sunlight reflected from Saturn itself. To see it, slide your cursor over the image (or follow this link). Other Cassini images of Mimas include the small moon’s large and ominous Herschel Crater.

Photo of the Week

Crescent Enceladus

Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explanation: Peering from the shadows, the Saturn-facing hemisphere of tantalizing inner moon Enceladus poses in this Cassini spacecraft image. North is up in the dramatic scene captured last November as Cassini’s camera was pointed in a nearly sunward direction about 130,000 kilometers from the moon’s bright crescent. In fact, the distant world reflects over 90 percent of the sunlight it receives, giving its surface about the same reflectivity as fresh snow. A mere 500 kilometers in diameter, Enceladus is a surprisingly active moon. Data collected during Cassini’s flybys and years of images have revealed the presence of remarkable south polar geysers and a possible global ocean of liquid water beneath an icy crust.


Photo of the Week

Daphnis the Wavemaker

Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explanation: Plunging close to the outer edges of Saturn’s rings, on January 16 the Cassini spacecraft captured this closest yet view of Daphnis. About 8 kilometers across and orbiting within the bright ring system’s Keeler gap, the small moon is making waves. The 42-kilometer wide outer gap is foreshortened in the image by Cassini’s viewing angle. Raised by the influenced of the small moon’s weak gravity as it crosses the frame from left to right, the waves are formed in the ring material at the edge of the gap. A faint wave-like trace of ring material is just visible trailing close behind Daphnis. Remarkable details on Daphnis can also be seen, including a narrow ridge around its equator, likely an accumulation of particles from the ring.

Photo of the Week

NGC 6357: Stellar Wonderland

Image Credit: X-ray: NASA/CXC/PSU/L. Townsley et al; Optical: UKIRT; Infrared: NASA/JPL-Caltech

Explanation: For reasons unknown, NGC 6357 is forming some of the most massive stars ever discovered. This complex wonderland of star formation consists of numerous filaments of dust and gas surrounding huge cavities of massive star clusters. The intricate patterns are caused by complex interactions between interstellar winds, radiation pressures, magnetic fields, and gravity. The featured image includes not only visible light taken by the UKIRT Telescope in Hawaii (blue) as part of the SuperCosmos Sky Surveys, but infrared light from NASA’s orbiting Spitzer Space Telescope (orange) and X-ray light from NASA’s orbiting Chandra X-ray Observatory (pink). NGC 6357 spans about 100 light years and lies about 5,500 light years away toward the constellation of the Scorpion. Within 10 million years, the most massive stars currently seen in NGC 6357 will have exploded.

Photo of the Week

The Extraordinary Spiral in LL Pegasi

Image Credit: ESA, Hubble, R. Sahai (JPL), NASA

Explanation: What created the strange spiral structure on the left? No one is sure, although it is likely related to a star in a binary star system entering the planetary nebula phase, when its outer atmosphere is ejected. The huge spiral spans about a third of a light year across and, winding four or five complete turns, has a regularity that is without precedent. Given the expansion rate of the spiral gas, a new layer must appear about every 800 years, a close match to the time it takes for the two stars to orbit each other. The star system that created it is most commonly known as LL Pegasi, but also AFGL 3068. The unusual structure itself has been cataloged as IRAS 23166+1655. The featured image was taken in near-infrared light by the Hubble Space Telescope. Why the spiral glows is itself a mystery, with a leading hypothesis being illumination by light reflected from nearby stars.