Summer Nights
Warm weather is an obvious factor in luring people outdoors - be it the summer cottage, Provincial Parks or the favourite campsite. No words can describe the sense of awe and amazement as you lay under a moonless canopy of stars, far from city lights and the veil of light pollution. From dashing meteors and the passing of high orbit satellites to the rising of the majestic Milky Way and the pastels of the Northern Lights, the mystical sky intrigues everyone. The sky is definitely alive.
Aside from our personal observing sessions, numerous public star parties are slated this summer and fall across the country. Here, dedicated astronomers haul out their scopes to bring the wonders of the night to the average person. If you have never gazed at the Moon or celestial object through the eyepiece of a telescope, I urge you to do so. Check for a local club in your area.
Although summer nights are warm, they are unfortunately short especially the end of June. There is however a multitude of favourite targets to find, adore and share with people. During my star nights at campgrounds, I first like to start the night by pointing out the vast “summer triangle”. It consists of three constellations and the stars of the show are Vega in the constellation Lyra the Harp, Altair in Aquila the Eagle and Deneb in Cygnus the Swan. Their distances are 25 ly, 16 ly, and 3,200 ly respectively. In fact, the swan glides along with the misty band of the Milky Way Galaxy. This misty arch is the glow of millions of distant stars too far to be resolved.
Our first telescopic object is Alberio – the head of the Swan. This object located some 380 ly from us, is the most beautiful double star in the entire sky. One member consists of a golden yellow and the other a handsome blue. Depending on the observer, colour schemes vary a bit. Next, we move to the Ring Nebula in Lyra – M57. This planetary nebula is a classic example of how our Sun will eventually end its long life. Fear not, its fuel supply is good for another five billion years. When the Sun does exhaust its fuel, it will become a red giant, growing to the orbit of Mars thus vapourizing the red planet, Earth, Venus, and Mercury. As its outer shell escapes the weak clutches of the dying Sun, it forms a gaseous shell around it.
For diehard galaxy hunters, nudge your scope a little north and find the illusive face-on spiral IC1296. Listed at a faint 15th magnitude, we will need a great sky and large optics to locate this item. IC1296 is estimated to lie about 200 million light-years from us compared to M57’s mere 2,000 light-year distance. IC1296 is far too faint an item to be shown at public star parties. Stick with the brighter objects.
For a change of pace be sure to swing to the globular cluster M13 in Hercules. At close to 22 thousand light-years from us, this supercluster contains an estimated one million stars. The beauty is discerning globulars is to try and resolve stars to its central core. Depending on the optics used you will literally see a 3D effect of stars behind stars. Even at its great distance, M13 can be glimpsed naked eye under good sky conditions. While in Hercules, move over to M92, another globular cluster but not as populated but still an amazing view.
The summer sky is home to sparsely open clusters as well as its giant cousins – the globulars. NGC 6709 in Aquila is a loose gathering of about 40 Suns, located some 2,500 ly from us and is just below
naked-eye visibility at magnitude 6.7. Still in Aquila head to another favourite the Wild Duck – M11. Your eye will witness a beautiful peppering of evenly lit stars and is accented by a brighter central member which is only a foreground star. Another show stopper is the Double Cluster in Perseus. Just as the name suggests, two open star groups fill the eyepiece. Keep the view as wide as this one. The double cluster’s two components are 7,400 and 7,700 light-years from us and the average person can still locate its naked-eye under dark conditions. In Cygnus, the subtle filaments of the Veil nebula are the lingering remnants of a star that went supernova some 160,000 years ago. Dark skies are definitely required and a nebula filter would not hurt. Just below Albireo, we come across the Dumbbell nebula – M27 in Vulpecula. Measuring 8 X 6 arc minutes or about the quarter size of the moon, this planetary is a delightful target. Now move a little southwest to M71 in Sagitta. This highly resolved globular glows at magnitude 8.3.
Moving down the centre of the Milky Way be sure to show a stellar nursery M8. Commonly known as the Lagoon nebula this glowing area of gas is slowing creating stars at its core. In fact, you can see a young, million-year-old cluster off to its side. Visible to the naked eye under dark conditions, this 5,200 light-year stellar incubator is larger than the full moon. Just above it is M20 the Trifid Nebula which is a great example of the (red) emission nebula, again developing stars, and the (blue) reflection nebula, bouncing starlight off its gaseous region. You, however, will not see colour in an eyepiece. Only photography allows us this.
Remember this is your last chance to catch the planet Saturn as it swings under the Beehive cluster – M44. This stellar portrait will not painter until early September mornings in the year 2064 or a mere three Saturnian years. Mars will sweep very close on the 15th.
The Planet Jupiter is putting on a beautiful show, revealing its cloud top features namely; bands festoons, white spots and the Great Red Spot (GRP). Don’t forget to try locating a new feature dubbed Red Spot Junior which is half the size of the GRP or about earth-sized. Refer to page 203 of the RASC’s Observer’s Handbook for transit and shadow timings. With a moderate size instrument, you can see the Galilean moons cross the Jovian face.
And finally at 07:34 UT (2:34 eastern time) on June 22nd, the Sun will climb to its highest point in the sky signifying the first-day summer in the northern hemisphere and winter in the south. From this point on, our nights will begin to get a little longer. This month’s Strawberry Moon will be full on June 11th at 18:03 UT.
Enjoy these summer nights, just don’t forget the bug spray.
Until next month – clear skies everyone.
Gary Boyle