Astro Bob blog: Changing tires in the company of a cometAnother unexpected adventure while basking under a Comet McNaught's glow, plus a new finder chart to see the comet while it's at its brightest.
By: Bob King, Duluth News Tribune
Changing tires in a comet's company
Comet McNaught made a fine sight this morning in Perseus in this photo taken around 2 a.m. While the short tail immediately to the right of the comet's head was not visible in binoculars, the long tail was and appeared like a delicate smoke trail. Details: 200mm lens at f/2.8, ~3 minute time exposure at ISO 800 on a tracking mount. Photo: Bob King
I don't know why each time I'm out before dawn to see Comet McNaught a little extra adventure gets tossed in the mix. I drove north out of Duluth last night to escape the clouds and set up telescope and camera on a gravel road at a location with a wonderful 360-view of the sky. This time the sky was very clear, no clouds to mess with, and the comet was a spectacular sight. It's now circumpolar for the northern U.S. and Canada and never sets, so I first spotted McNaught about 12:45 a.m. low in the northeastern sky in Perseus. Through 10x50 binoculars the comet's head was small and looked like a fuzzy greenish star. A wispy tail reached two full moon diameters up and to the right (northwest). Later, when the comet was higher in the sky and seen through thinner, more transparent air, I could easily trace the tail a full 2 degrees or four moon diameters.
This updated finder chart for the comet shows it moving from just below Alpha in Perseus toward the bright star Capella in Auriga. The chart shows the northeast sky around dawn or about 2:45-3 a.m. for the northern U.S. The best place to start is with the familiar W of Cassiopeia. Drop down from there to Alpha and then sweep your binoculars over the appropriate spot according to the date. Maps created with Stellarium
I couldn't wait to see what the 15-inch scope would show and, oh my god, it was incredible. A brilliant, green-blue head and a tail that stretched all the way across the field of view. The tail was so sharp and narrow it reminded me of a fresh airplane contrail. Breathtaking.
Even though McNaught remained basically in one spot during the time I viewed it, its form evoked the movement of a fireball streaking across the sky. You might think I had a bit of an unfair advantage with the telescope I used, and you'd be right, but I have no doubts that any telescope under good sky conditions will show both the head and tail of this comet. All of McNaught's major features were also visible in ordinary binoculars -- just fainter.
This wider view of Perseus (including Alpha) gives you a better idea how skinny
the comet's tail is and how stellar its head appears. Photo : Bob King
I must have looked at the comet 16 times between 1 and 3 a.m. and each time its marvelous, living form mesmerized. Deep inside the coma (head) a blazing fuzzy star -- the pseudo-nucleus -- marked the center of cometary activity. Another time I tried to follow the tail as far as possible both into the coma and out further to where it broadened and faded into the sky background. At dawn's start, when McNaught was highest in the sky, I glimpsed it on several occasions with the naked eye alone as a very faint, soft 'spot' below the star Alpha Persei.
A small display of northern lights started up around 2:30 this morning and glowed green under the star Capella. Details: 24mm lens at f/2.8, 35-second exposure at ISO 1600. Photo: Bob King
About this time a very "gentle" display of northern lights kicked in just above the north-northeastern horizon near the rising star Capella. A perfect way to end the night. Oh, but wait. While packing up my equipment, I remembered to check the tires. On the way out, the car was pulling to the left more than usual. A quick swing of the red flashlight on the left front tire revealed what I'd feared but forgotten in my comet-watching pleasures. It was completely flat.
With the aurora still simmering away and the very first white-throated sparrows tentatively beginning to sing, I changed the tire. It was probably the most at peace I've ever been while performing this activity.
Moon too low to see well last night? Tonight it'll be much easier. Look below the planet Venus during mid to late evening twilight tonight. Very nice pairing!