With no baseball season yet underway we’ll have to depend on Comet NEOWISE for home runs for the time being. I hope you’ve had the opportunity to this delicate spectacle. If you’ve been unable to do so because of schedule or weather, hang in there. The comet will be around for a while. Although it’s slowly fading (now around magnitude 1.5-2) it’s still very obvious in binoculars and faintly visible with the naked eye even from suburbs and some cities.
Here’s a report I received today from Jim Twellman, one of our readers:
“I’m in Lake St Louis, a suburb 30-some miles west of St Louis. I viewed the comet the last 3 mornings. Today the sky was nearly crystal-clear, and I viewed the comet naked eye before ever getting the binoculars out. No need to use the binos to hunt for it. I was able to see it naked eye here from about 4:22 to about 4:55 AM, but those last 5 minutes it was diminishing rapidly.”
I last saw the comet on July 8 before it was overtaken by clouds. Its visible tail had doubled in length (to 6°) from the previous morning, and it was a little brighter to the naked eye, too. Telescope and binoculars gave the best views. Because the sun is rising a little later and the moon is waning, dawn views of the comet and its long tail should improve a little in the coming days even as NEOWISE commences to fade.
I did a careful check and it will be possible to see NEOWISE at dawn through July 18. At the same time, you can watch for it in the evening twilight starting about July 12 when it will appear in the constellation Lynx the lynx which neighbors Ursa Major. From July 12-18 you can see it at both dawn and dusk.
Once it pushes into the evening hours it will climb the northwestern sky and be more convenient to view, but it will be fading, too. I always recommend seeing transient phenomena like comets when they’re brightest and at the earliest opportunity if for other reason than the weather. You never know when you’ll be slammed by storms and like and for how long.
NEOWISE is amazingly colorful, an aspect I tried to capture in the sketch and displays a wonderful, bifurcated (split in two) dust tail. Dust is released when comet ice vaporizes in the heat of the sun. Sunlight exerts pressure on the dust, blowing it back behind the icy comet to form a tail. We see tails because the particles are excellent at scattering sunlight just like dust or smoke does on Earth.
Recently, the comet developed a second tail called the gas or ion tail. It’s faint, pale blue and very narrow. Few have seen it yet, but it does show in deep exposure photographs like the one above. Sometimes bright comets develop a very faint sodium tail made from glowing sodium atoms. No one has seen that yet assuming there is one.
I’ve included a new map for you so you can see where the comet is headed as it moves into the evening sky. If you do spot this beauty please send me a report in the comments area or friend me on Facebook and comment there. Clear skies!