In astronomy, there are good nights and there are bad nights.
A good night is a cosmic gift: cloud-free skies and transparent atmosphere are basic requirements before you get started.
Our last outing at Miles Canyon Lookout Point was one of those wonderful sessions where sky conditions were as perfect as the temperature. So, with no further adieu, here is our story:
Arriving at the lookout point, a half-illuminated moon greets me in a clear and stable night sky. Next, I am greeted by Yukon mosquitoes (I had forgotten how much of a joy these little fellows could be). Setting up my gear was a snap as I took only my big Dobsonian telescope and small Borg refractor.
It is 11 p.m. We are ready to go, but the night sky is looking pretty bright. Might as well check out the moon.
The moon is impressive in binoculars or a small telescope, but in a large telescope the view is rich, detailed and presents unparalleled contrast.
The greatest detail is at the Terminator Line where the illuminated region of the moon meets the dark side. Here, you will find half-lit craters and detailed views of the mountain ranges.
The Apennine Mountains are an excellent example of this type of observing: towering canyon walls, resting in dark shadows, are seen as telescope power is increased from 40 to 150. Shadows from lunar mountain peaks stretch across the smooth, grey valley floor like slender fingers of darkness. Large valleys, half-illuminated, give the appearance of something definitely not of this Earth.
Along the Terminator Line is every kind of crater you could ever wish to see. Shallow craters, with small, smooth undefined walls and large, deep craters with walls lined with ledges and outcroppings, present a view alive with detail and contrast.
One of my favourite views is a crater with a mountain in the middle. When sunlight hits the mountaintop, there is a perfect dot of light where the lunar mountain peak was. An added bonus: you will see a small shadow, from the illuminated peak, streaking across the crater floor.
Another favourite pastime is surfing lunar seas and hunting long-forgotten mountains and craters. At a quick glance, there appears to be few or no features but, with patience and a polarizer filter for your telescope, detail can be coaxed into the eyepiece.
If you own a telescope or large binoculars, you will want one of these filters. Do yourself a favour and spend the extra dollars for the variable polarizer, adjustable with a simple twist, which offers the best viewing. Even when the moon is fully illuminated, this filter helps.
My favourite telescope for observing the moon is my Dobsonian, built for wide-field, deep-space observing – awesome for sailing lunar vistas.
The pictures accompanying this column were taken with 40- to 100-power magnification. It’s not uncommon to view at powers in excess of 400 times or more, when conditions permit.
Cameras capture a wealth of detail, but the human eye distinguishes subtle changes in light and texture, providing the 3D effect. The best way to view the moon is at the eyepiece.
Saturn was high in the sky, the rings open a bit more, but basically edge on. With rings in this configuration, a few moons are visible. On Friday night, we observed three moons and, on Saturday night, we saw four: a most-excellent view, especially with two moons so close to the planet.
On Saturday night, some pleasant surprises were added to our already-outstanding weekend. Cygnus (a.k.a. Northern Cross) is making an appearance in the Yukon Night Skies.
Our first peek into this constellation was the bright, double star, Albireo, a gold-and-blue double star. In coming weeks, Cygnus will rise higher off the horizon and we can explore the Veil Nebula and the rich star fields in this region.
The Ring Nebula (a perfect smoke ring that floats in space), found in the constellation of Lyra, was positioned high in the sky, offering a good view.
The Hercules Cluster is found in the constellation bearing its name. With the moonlight, we did not get the best view, but boosting the power to 200-plus magnification helped. Stars were resolved, but certainly not the view you get on a moon-less night.
We had some new people out and wanted to show them a variety of deep-sky objects in the Yukon Night Skies. Easier said than done, as many galaxies are washed out by the overpowering moonlight.
We pointed the Dobsonian overhead and located M81 and M82, my favourite galaxies. M82 is an edge-on, irregular galaxy, and M81 is a face-on spiral galaxy. Both easily seen but, again, not with the detail you would expect on a moon-less night.
I was happy to see this pair of galaxies, especially with an abundance of moonlight in the sky and considering they are eight-million light years distant.
To complete our viewing, we checked in on the famous Double Cluster. This open double star cluster fills the eyepiece with so many stars that it leaves a person with a sense of awe and amazement. In moonlight, the view was still pleasing – not as many stars and in a much-smaller field of view. Still, a pretty sight.
We would be glad to take you for a Yukon Night Skies star tour. E-mail [email protected] to be kept informed of upcoming sessions.
Clear skies, from James “Deep Sky” Cackette.
James “Deep Sky” Cackette can be reached at [email protected]. See his photo adventures on Facebook at Yukon Night Skies.