Category: Comets

Catalina and the Pinwheel

14/1/2016

Comet Catalina is currently well placed for UK observers wishing to see it. The comet is tracking north in the sky and over the next week it will bypass the familiar seven stars of The Plough.

An interesting photographic opportunity occurs on the night of January 16th (going into the early hours of the 17th) when the comet will be close to the celebrated double star Mizar (and Alcor) and a bright-ish galaxy called M101 (the Pinwheel).

The picture above is a Stellarium rendition of Mizar, Comet Catalina and the Pinwheel Galaxy. This is the late evening of January 16th. But given that the moon is above the horizon until just after midnight, best views (and pictures) will be obtained during the early hours of the 17th. This is a wide field of view, so I'll try to capture this with the Nikon D80 mounted directly onto my HEQ5 Pro mount; I think shooting at 200mm will frame the region nicely!

Catalina and Arcturus

29/12/2015

Comet 2013 US10 Catalina has been in the morning sky for northern observers since the start of December. Not that there's been much chance to see it! The weather here has been mostly appalling for much of that time.

For a few days around the New Year period Catalina will buzz past Arcturus - the brightest star in the northern sky. Arcturus is an orange giant star - there really is no mistaking it in high in the south east before dawn breaks. Arcturus provides an easy signpost to Comet Catalina as the year ends.

Looking southeast at 6am on 31-Dec-2015. Arcturus is high in the sky; Comet Catalina very close by.

A clear transparent sky away from light pollution is essential to view the comet. It isn't quite bright enough to be visible without optical aid: binoculars or telescopes will easily show it.

Here is a closer view of the sky around Arcturus. The star and comet will appear closest together in the sky on New Year's morning.

Approximate binocular view towards Arcturus as Comet Catalina passes around New Year.

A more detailed finder chart for the comet can be found here.

Comet Catalina coming soon!

7/11/2015

Comet 2013 US10 Catalina will appear in the morning sky for UK observers from the end of November. It looks like it will become a binocular object at least; fingers crossed that it becomes brighter still!

Here's a finderchart showing the trajectory of the comet during December and early January.

Comet Catalina is tracking north very rapidly. During December it moves from Virgo into Bootes. On the first day of 2016 the comet will pass within 1 degree of Arcturus - the brightest star in the northern hemisphere of the sky. The contrasting colours of orange Arcturus and the dusty comet (perhaps with a green coma) should make an excellent photo!

Comet Catalina reaches perihelion (closest point to the Sun) on November 15th. The comet will be 0.82 AU (123 million km) from the Sun; between the orbits of Venus and Earth. Catalina won't be visible from the UK until it has moved further north, away from the Sun's glare towards the end of the month. Comet Catalina will be closest to Earth on January 17th 2016, at a distance of 0.72 AU (108 million km).

Comet Catalina was discovered by the Catalina Sky Survey in 2013. It is a dynamically new comet; it was perturbed from the Oort Cloud several million years ago and the trajectory after perihelion shows it will likely be ejected from the solar system - never to return.

Catalina is predicted to fade slightly after perihelion with brightness estimates putting it between 5th and 6th magnitudes. Dark skies away from light pollution should allow anyone with binoculars and telescopes to view the comet.

Comet Lovejoy departs

23/1/2015

Comet 2014 Q2 Lovejoy will be at its closest point to the Sun on January 30th - a mere 120 million miles from it. Despite being further from the Sun (by 27 million miles) than us, Comet Lovejoy is glowing in our northern sky more brightly than any comet since Comet 2011 L4 PANSTARRs in 2013. Comet Lovejoy is starting to fade but remains excellently placed in the northern sky for UK astronomers.

The chart below shows the path of Comet Lovejoy from the last week of January until the start of March. During this period the comet is expected to fade from magnitude +5 to +8. Comets are somewhat unpredictable and those estimates don't take account of sudden outbursts caused by unstable conditions on the comet.

During the past few weeks I've tried to get pictures of Comet Lovejoy on lots of occasions. Here are a couple of my best pictures:

That delicate ion tail has been very difficult to see both visually through the telescope eyepiece and on camera. It's not helped that someone thought it a good idea to build Newcastle not far from here. And even less of a good idea to fill it with streetlights. Makes it almost impossible to get dark skies from my back garden.

Anyway...

The comet begins February in the constellation Andromeda, near second magnitude star Almach (itself a superb double star through telescopes). An excellent photographic opportunity occurs on the evening of February 20th/21st when the comet will be very close to the Little Dumbbell nebula (M76) in Perseus.

During March the comet will fade to the point where only telescopes can resolve the coma as it begins to blend into the rich starfields of Cassiopeia.

The Comet and the Bull

13/1/2015

Comet 2014 Q2 Lovejoy is really starting to put on a great show for UK astronomers. At last, it is north of the celestial equator and shining brightly enough to be visible to the naked eye. My camera remote control has died so the pictures below were taken with my dad's superior Nikon D90.

This was my view of the southern sky at about 6.30pm last night:

Comet Lovejoy was easily visible in the sky. At first glance it looks like a faint star but using averted vision it does look somewhat fuzzy. The cometary nature is revealed easily with binoculars.

A closer view of Comet Lovejoy as it passes through a beautiful part of the sky near Taurus, the Bull.

Finally, here's a telescope view of the comet revealing many delicate streams of material pushed away from the comet by the solar wind.

Comet Lovejoy was about 45 million miles from Earth last night. Although it's getting further away from us, it is continuing to approach the Sun. It will remain an easy target over the next couple of weeks for binoculars and small telescopes.

Comet for the New Year

10/12/2014

Credit: Rolando Ligustri

There'll be a treat in the night sky for owners of new telescopes after Christmas. Recently discovered Comet 2014 Q2 Lovejoy is expected to brighten and become visible in the evening sky at the end of December.

Observers in the southern hemisphere have been favoured so far but the comet is tracking north and will become visible from Northumberland from the last week of December.

Here's a star chart showing the northwards drift of the comet during the first weeks of 2015.

I've left the magnitude estimates off the chart but astronomers are expecting Comet Lovejoy to be around 6th, maybe even 5th magnitude during this period. That will put it within easy reach of binoculars and small telescopes. From especially dark sites it might attain naked eye visibility.

Comet Lovejoy is very well placed for UK astronomers in the New Year. After beginning the month close to the southern horizon in the early evening sky it rapidly climbs north from Lepus (the Hare) through Eridanus (the River) and into Taurus (the Bull).

Just a bit of background on the comet itself. It was discovered by veteran comet hunter Terry Lovejoy in August 2014 and was his 5th comet discovery. This one is going to reach a similar brightness to one of his previous comets - 2013 R1 - which was visible in the UK in late Autumn 2013.

2014 Q2 Lovejoy will be closest to Earth (0.469 AU / 43.6 million miles) on January 7th. It will reach a perihelion (closest to the Sun) distance of 1.29 AU (119.9 million miles) on January 30th. The entire orbit of this comet lies outside Earth's orbit and that's why the comet can be seen almost on the opposite side of the sky to the Sun despite being near perihelion.

I'll post updates on Comet 2014 Q2 Lovejoy and, hopefully, some pictures over the coming weeks.

A PDF finder chart is available here.

Crumbling Comets*

9/11/2014

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The Taurid meteor shower reaches peaks on November 3rd and again on the 12th. For many amateur astronomers the month of November is associated with the Leonids - a much more famous shower which has occasional stormy outbursts. But I have to say, I prefer the Taurids because they have a more interesting backstory!

About 20,000 to 30,000 years ago a huge comet - perhaps 50 km in diameter or more - became embroiled in a series of close approaches to the planet Jupiter. Nothing unusual about that - Jupiter has a huge family of comets even today and we;ve seen first hand how Jupiter can change comet orbits and even tear comets apart.

By E. Kolmhofer, H. Raab; Johannes-Kepler-Observatory, Linz, Austria

For that big, old comet nucleus, with its much larger surface area would have experienced a huge amount of solar heating as it approached the Sun. It would've been a spectacular sight in the skies of our ancestors. Think of Hale-Bopp (on the left) but much bigger and brighter in the night sky. After interaction with Jupiter the new orbital period - a few years, rather than centuries or millenia - subjected this giant ice-world to more frequent and intense levels of activity. The rapid pace of the comet going around the Sun also accelerated its demise and fragmented the nucleus. Each fragment may have become a dramatic comet in its own right. As the centuries rolled by each fragment may have split further until complete disintegration occurred or until all the volatile materials boiled away into space - leaving, to all intents and purposes, an object resembling an asteroid.

These days, all we have left of the original giant progenitor comet is a small, faint comet with an orbital period of 3.3 years (called Encke's Comet) and a complex series of dust streams which the Earth encounters in November each year. The dust released by the fragmented nuclei over periods of thousands of years have gradually been spread out into a broad swathe of the inner solar system. Actually, the Earth also encounters one of the streams during June but during the daylight hours. It is speculated that the devastating Tunguska event of 1908 was due to a larger fragment disintegrating in the Earth's atmosphere. That's another story.

On Earth, each November, we see the remains of a giant comet, streaking into our atmosphere as a shower of shooting stars and appearing to come from the constellation Taurus. It takes the Earth weeks to cross these lanes of dust and in doing so we encounter two distinct peaks - evidence of the complex evolution of the meteor orbits. So in November we see the Northern Taurids near the start of the month and and the Southern Taurids around two weeks later. Activity is fairly low - typically about seven or eight per hour. Compare this to, say, the short sharp spike in activity of the Perseids in August or the Geminids in December.

Will we see another giant comet? Interestingly, there is evidence to suggest a big comet, seen in our skies in 1106, broke apart and the sun-grazing fragments have produced several of the best comets of past millennium.

And in the future? An intriguing object called Chiron, appears to be a giant comet although it was initially identified as an asteroid back in 1977. With a diameter of around 180 km Chiron has an orbit which takes it from within the orbit of Saturn to just beyond Uranus. Observations in the 1980s showed it to be developing a coma as it approached its nearest point to the Sun. Mathematical modelling also revealed the orbit of Chiron to be unstable and chaotic over long periods. In a million years it will probably have been put into a completely different orbit within the solar system or perhaps ejected completely the neighbourhood. But it can't be ruled out that Chiron will one day be a spectacular giant comet gliding regularly through the inner solar system.

There's also the possibility that a swarm of Kreutz sungrazing comets (probable fragments of the Great Comet of 1106) are en-route to the inner solar system and will arrive in the coming decades. If true then there are good prospects of seeing another Great Comet (or Comets).

So, no major showers this month. But chances are good this month that if you spend enough time outside watching the sky you will see the remnants of an ancient, giant comet ending their existence in a brief flash of light.

For a more in depth technical article about the Taurids --- see here.

* Had to fight an urge to add the word Batman! to this title.

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Finding Comet 2012 K1 PANSTARRS in September

31/8/2014

C/2012 K1 PANSTARRS is a binocular comet for UK observers this month but it's a tough spot in the morning sky before dawn.

The chart below shows the motion of the comet during September. Look towards the southeast at around 5am.

Magnitude (brightness) estimates are shown below the date on the chart. The comet is tracking south through the constellation Hydra. Comet PANSTARRS is getting further from the Sun but the Earth is moving closer to the comet - hence the slight increase in brightness.

Finding Comet Jacques in September

31/8/2014

Comet 2014 E2 Jacques continues its journey across the sky and along the Milky Way in September.

The magnitude (brightness) estimates are shown below the dates. The is visible with binoculars at the start of the month but will require moderate sized telescopes to be seen by the end of September. Having said that, Comet Jacques is superbly placed for UK observers; visible for much of the night for most of the month and almost overhead for the first coople of weeks in September. Also unfortunate is that observations will be hampered by moonlight during the first half of September.

There are a couple of nice photo opportunities before Comet Jacques departs our sky. On the evening of September 14th the comet will be less than 1 degree from the celebrated double star Albireo in Cygnus. And on September 19th and 20th it will pass to the west of Brocchi's Cluster (aka The Coathanger).

I took this picture on August 30th when Comet Jacques flew past the Garnet Star in Cepheus.

Comet Jacques is leaving the inner solar system and activity on the surface is shutting down. It may return to our skies one day - but not for at least 22,000 years.

An 83,000 mph snowball

29/8/2014

Not too many clear nights this month but enough to get some pictures of Comet 2014 E2 Jacques. The comet is well placed for UK observers but doesn't look that impressive through small telescopes. It's great that such an unimpressive comet is attracting media attention ;-)

Comet Jacques is moving rapidly across the sky. The problem with taking pictures is that I've been limited to exposures of just 2 minutes through the DSLR on the telescopes. More than that and the comet smears across the image. The middle picture above was an attempt to autoguide on the comet - forcing the telescope to track the motion of the comet rather than the stars. Unfortunately the weather wasn't good that evening but the method worked.

The movie above was compiled from 29 two minute exposures collected on the evening of August 28th. The rapid motion of the comet makes a nice (if short) movie. Comet Jacques was moving at about 37 km/s and was about 84 million km from Earth. It was shining at around 7th magnitude.

I'm hoping for a clear sky tomorrow as Comet Jacques sails past the Garnet Star in Cepheus. Should make a nice photo with contrasting colours.

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