The Scottish Comet

A bit of a challenge for you this week, which I’m can say with a fair degree of certainty that none of you will take up, Comet McNaught. I did mention this comet before in the May round up, but couldn’t find any easy way of placing it for you, well now there is and its now naked eye bright. But and it’s a big but, you’ll have to get up very early or better still go to bed very late. Mid-June is when Comet McNaught should be most interesting, offering the best compromise between its increasing brightness and its decreasing altitude at the start of dawn. Moreover, the sky will be free of moonlight. It’s about 15° high in the nor, nor east as the sky starts to grow light on June tonight, but it appears roughly 1° lower every day after that. The comet passes Capella on the 21st, and it’s very low by the 24th, when it passes through Auriga, the constellation named after the guest house not the guest house it self.. By now Comet McNaught may be as bright as 4th magnitude, but moonlight is returning.

Comet McNaught June 1oth.

And Capella is the key to spotting the comet. Cappella is the brightest star in Auriga, the sixth brightest in the sky, and there’s really nothing else in the early low Northern sky at the moment, apart from the inevitable cloud that will make all this redundant. McNaught is moving towards Cappella up to the 21st. Find Cappella with binoculars and slowly move them eastward parallel to the horizon and you should find it, otherwise just scan randomly in the general area.


It’s quite a striking green, with a blue tail, pictures and a guide of course on the blog. Gas molecules of cyanogen (CN) and diatomic carbon (C2) in a comet's coma fluoresce green in sunlight. Ions of carbon monoxide (CO+) and carbon dioxide (CO2+) in the ion tail fluoresce blue. A comet's dust tail, on the other hand, simply reflects sunlight and is basically Sun-colored: pale yellow-white. This is clearly not a very dusty comet.

As for the planets no real change at all.

Mercury barely rises before the sun, so forget about it.

Mars still forms a striking pair with bluer Regulus in the late evening western sky.


Jupiter rises around 1 or 2 a.m. daylight saving time and shines high in the southeast before dawn.

Saturn (magnitude +1.1, in the head of Virgo) glows in the southwest during evening. The diagonal line of Saturn, Mars, and Venus is shrinking week by week. The three planets will bunch up low in the sunset in early August.





That was your night sky for the week ending on the 377th anniversary of the Catholic Church forcing Galileo to recant his view that the Sun, not the Earth, is the center of the Universe. He was wrong anyway, but it was a big step up the road.

Jupiter Dinged Again

Impact Point

June 2010 Around 11pm

Nothing overly exciting going on at the moment, unless you live on Jupiter, which has just had another impact event. The fireball appeared in the giant planet's atmosphere June 3 at 20h30m GMT.

Jupiter has been the target of several huge impacts within the last two decades. In July 1994, 21 fragments of Comet Shoemaker-Levy 9 hit the planet, any of which would have wiped us out. More recently, a 600 metre wide asteroid struck Jupiter on July 18th last year. This makes two impacts in a year twice in a year, which is actually quite alarming. Now a 600 metre meteorite is no where big as the 10kilomtre job that wiped out the 70% of everything including the dinosaurs 65,000,000 years. But if one landed in the North Atlantic at a 120,000 miles per hour plus there wouldn’t be much left of Europe or the Eastern Sea board of America. But not to worry Bruce Willis would sort it out in that rather fetching vest of his. But just to reassure you it all happens on Jupiter because the planet is so big it attracts these rogue celestial mountains and throws them out of a stable orbit, it’s like the solar system’s Hoover. Video below

Now more mundanely Mercury is back in the morning sky but to dim and too close to the sun to bother with.

Venus is still very much with us in the north western sky during and well after Sunset. Venus, Pollux, and Castor line up straight as twilight fades on Friday. You just can’t miss Venus its fantastically bright at moment. It’s on the other side of the Sun at the moment and in a telescope it shows as an almost complete but tiny disc. It’s getting nearer all the time and as it comes around the sun toward us, it will gradually change to a much larger crescent, by late summer. Venus is as high in twilight as it will appear this year; soon it begins its slow summer sink.

Mars glows in the west, forming a striking pair with bluer Regulus (magnitude +1.4). Mars has been closing in on Regulus for weeks. They passed each other on June 6th, 0.8° apart — a pencil-width at arm's length. In a telescope Mars is just a very tiny blob, 5.8 arcseconds in diameter.

Jupiter rises around 2 a.m. and shines in the southeast at dawn. Nothing else there is nearly so bright.

Saturn (magnitude +1.0, in the head of Virgo) glows in the southwest during evening. Take a look at the star map for Scilly on the blog if you want to find it.

And that was your night sky for the week ending on the 133rd anniversary of Henry Ossian Flipper becoming the first African American cadet to graduate from West Point.