This winter has seen a succession of storms batter the UK and clear skies have been few and far between. I managed to grab a couple of hours observing the other day and took enough pictures to compose a couple of images.
The first is Comet Catalina.
Through the eyepiece of the 80mm refractor the comet looks like an elongated fuzzy patch of light. The camera picks up the dust tail a little better. Catalina is moving away from both the Earth and Sun now and it will fade substantially in the coming weeks.
The second is Orion's Sword - a region below the Belt stars which contains the Orion Nebula.
This one was taken with a modified Nikon D90 (making it easier to pick up the red light of hydrogen emission).
A line of bright planets has formed in the morning sky but the weather is back to normal service of rain and wind.
Take a look at this simulated scene from the morning of January 27th 2016 at around 7am.
The view is south facing at around 7am. There are five planets scattered across the morning sky (six, if you include the one you're standing on!)
If you're in the UK then you'll have from about January 24th - February 8th to see all five planets.
The positions of the planets will be slightly different each successive morning; for example, Jupiter is apparently moving west (away from the Sun) whilst Venus is moving towards the Sun. These apparent motions are caused by our own vantage point on a moving planet as well as the real movement of the planets around the Sun.
Mercury will be the trickiest planet to see. Fortunately it is not far from Venus, the brightest planet: just look to the left of Venus and a little lower towards the horizon. You'll need a clear view of the horizon and any wisps of cloud may be enough to hide Mercury in a twilight sky. If you have binoculars then it should be easy to see Mercury.
The moon, which is visible in the picture above may help to identify the planets on various mornings over the next couple of weeks.
After the first week of February it will become very difficult to pick Mercury out of the morning twilight (from the UK at least). Venus is also drawing closer to the glare of the Sun. The other planets - Saturn, Mars and Jupiter - will continue to be visible in the coming months.
Although the planets look like they're in some kind of special alignment - that's not really the case. The planets always fall close to a line in the sky called the ecliptic and that's a consequence of the fact that the solar system is disk shaped, with the planets orbiting more or less level with each other (and the Earth).
What makes this configuration more notable is that the planets are all on the same side of Sun from our persepctive. Imagine if the Sun were somewhere between Saturn and Mars in the picture above; it would mean Mars and Jupiter (to the right) would be visible in the morning sky, whilst Saturn, Venus and Mercury (to the left) were in the evening sky. That's a more typical situation.
When viewed from above the solar system you can see the arrangement of planets isn't really a notable alignment.
The Earth's orbit is highlighted in red. The other planets are spread out in different positions along their orbits. If you draw a line from Jupiter - Earth - Mercury the angle at the Earth is around 110 degrees. For all the planets to be visible in the sky at the same time we just need that angle to be less than 180 degrees with the Sun outside of the line (to the left or right of the first or last planet respectively).
Seeing a line of planets like this is fairly rare! The last event like this occurred in the evening sky in the Spring of 2002.
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!
Venus has been a morning sky object for months. Saturn has been hidden behind the Sun until recently and has joined Venus in the sky before sunrise. They're moving across the sky a somewhat different speeds and in the second week of January the two planets pass each other.
For a few hours on the morning of January 9th the two planets will be separated by gap just 1/5th of the diameter of the moon. Unless your eyesight is fairly bad, they will still appear as two distinct points of light but it's still rare to see bright planets so close together.
Venus is much the brighter of the two planets; although smaller than Saturn it is much nearer to us and shrouded by highly reflective clouds.
Here is the simulated view through my 8-inch Meade LX10 with a 5mm eyepiece at around 6.30am.
Venus and Saturn look roughly the same size (the disk of Saturn, without the rings). Without any depth perception it might help if you know that the actual size of Saturn is nearly 10 times larger than Venus. Therefore, for them to look the same size, Saturn must be about 10 times further from us than Venus.
There are a number of other planetary conjunctions in 2016 - most will happen in the last quarter of the year.
Whilst not spectacular, Comet 2013 US10 Catalina remains an easy binocular object for UK astronomers. It began the year close to Arcturus and there a lots of great photos of that alignment at spaceweather.com. During January the comet continues to track north eventually passing The Plough and getting within ten degrees of the north celestial pole (and Polaris)
Comet Catalina should be visible with binoculars for the entire month. It is fading: the magnitude drops from +6 to +7 by the start of February. The comet is nearest to Earth on January 17th.
The best time to view Catalina is in the morning sky from about 3.30am until dawn breaks until around January 20th/21st. After that, the comet is so far north that it becomes circumpolar and never sets over the UK. But the optimum time to view Catalina during the last week of the month will be during the evening after the moon has set.
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.
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.
A more detailed finder chart for the comet can be found here.
These long winter nights are perfect for stargazing! Here's a brief look at the astronomical highlights of this month.
The innermost planet Mercury puts in an appearance in the early evening sky. Look towards the southwest about 40 minutes after sunset during the first week or so of the month to catch a glimpse of it. Jupiter rises around midnight and shines brighter than any other star in the evening sky. For early risers the planet Mars – looking distinctly orange – can be found among the stars of Libra. Venus is drawing further in to the morning twilight but remains easy to find in the southeast sky just before dawn. Venus will be very close to Saturn on the morning of January 9th; Venus is much the brighter of the two planets.
The planet Uranus remains observable in the evening sky in the constellation Pisces. Binoculars are sufficient to see this distant ice giant but telescopes at moderate magnification are necessary to discern the green-blue disk.
Stars and constellations
Here is a star chart showing the evening sky in January. It is designed for my home in Northumberland but will good enough for observers throughout the UK.
The southern aspect of the night sky is dominated by the constellation Orion (the Hunter) which occupies the sky about halfway between the southern horizon and overhead. The most prominent feature of Orion is the "Belt" - three stars in a near straight line. There are many sights to see with binoculars and telescopes in Orion. The most famous is the great Orion Nebula which is to be found below the Belt stars, in Orion's Sword. The nebula is a stellar nursery and the region glows because of one or two particularly hot, young stars within it. The Orion nebula is merely the tip of the iceberg! The stars of Orion lie in the direction of numerous giant clouds of hydrogen - a very long exposure of the region shows many, many more objects than are visible to the naked eye.
Auriga, the Charioteer, is almost overhead and the leading star Capella is a yellowish star at a distance of 45 light-years. The Milky Way looks particularly rich as it flows from Perseus, through Auriga and towards Taurus, the Bull. Aldebaran is the brightest star in Taurus and is an orange giant at a distance of 65 light-years from us; it is bloated, orange giant star nearing the end of its life. Following a line from Orion's Belt down to the southeast horizon will lead you to Sirius, the brightest star in the entire sky. The brightness is not a true indication of true luminosity; Sirius is just under 9 light-years from us and although it is somewhat more powerful than the Sun, it is far less luminous than Rigel. Rising in the east is the Sickle-pattern of stars marking the head of Leo, the Lion.
Jan 01 --- Comet Catalina close to bright star Arcturus in the morning sky.
Jan 02 --- Last quarter moon
Jan 02 --- Moon at apogee (furthest from Earth); 251,206 miles (404,277 km).
Jan 02 --- Earth at perihelion (closest to Sun); 91.4 million miles (147 million km)
Jan 04 --- Quadrantid meteor shower peak
Jan 05 --- Pluto conjunction with Sun
Jan 07 --- Crescent moon near Venus and Saturn in morning sky.
Jan 09 --- Venus and Saturn conjunction (about 5 arcminutes apart; very close!)
Jan 10 --- New moon
Jan 10 --- Moon and Mercury conjunction (very difficult to observe!; SW horizon around 4.40pm)
Jan 14 --- Mercury inferior conjunction
Jan 15 --- Moon at perigee (closest to Earth); 229,391 miles (369,169 km)
Jan 16 --- First quarter moon
Jan 17 --- Comet Catalina closest to Earth (108 million km).
Jan 19 --- Gibbous moon in the Hyades star cluster
Jan 24 --- Full moon
Jan 27 --- Moon and Jupiter less than 2 degrees apart.
Jan 27 --- Asteroid 115 Thyra at opposition (mag. +9.9, in constellation Cancer)
Jan 30 --- Moon at apogee (furthest from Earth); 251,378 miles (404,553 km).
Quadrantid meteor shower
The last major meteor shower of the winter is expected to peak during the early hours of the morning of January 4th. The Quadrantid meteors radiate away from the border of the constellations Bootes and Hercules and it is named after a now defunct constellation – the Mural Quadrant. The peak in 2016 comes on the evening of January 3rd, with the best time to observe being the early hours of January 4th. During the narrow peak, rates as high as 120 meteors per hour might be possible. There will be some moonlight interference from a waning crescent moon.
A gallery of some of my favourite pictures of the universe!
This is almost becoming a Christmas tradition for me; an elongation chart for the bright planets in 2016:
A high quality PDF version with much more information can be downloaded here.
The planets shown are Mercury (m), Venus (V), Mars (M), Jupiter (J) and Saturn (S).
This chart shows the positions of each planet relative to the Sun (middle) all through the year. The vertical axis represents the days and months of the year. The diagonal bands represent constellation boundaries. The wavy yellow band is a region close to the Sun in which it would be difficult to observe the planets. The wavy yellow line represents regions of the sky rendered invisible because of the proximity of the Sun. The shape of that wavy line explains, for example, why Mercury is easier to observe in the October morning sky than the September morning sky (even though it is further from the Sun in September). Also, the chart behaves like a game of PacMan; any planets reaching opposition 180 degrees west of the Sun wrap straight over to the evening sky on the far left. Think of this as being like an unwrapped cylinder!
Places where the lines intersect planetary conjunctions --- often beautiful (but not significant) events where the planets appear close together in the sky. There will be several notable conjunctions from August through to November 2016. Here are details of all the conjunctions potentially observable from the UK.
The numbers in the first column refer to the numbered conjunctions on the elongation chart.
Finally, the elongation chart was compiled in LaTeX and PSTricks using data from the JPL Planetary Dynamics website.
I'm about 7 weeks into a distance learning MSc in astrophysics with LJMU. Over the past two weeks the topic being covered was the interstellar medium (ISM) - the vast regions filled with gas and dust between the stars throughout the Milky Way.
During this time the weather has been mostly awful! But there have been a couple of clear nights and during those I've finally been able to try a modified DSLR on loan from a friend to get some images nebulae that are beyond the reach of my normal DSLR.
Here are two pictures taken by stacking dozens of images together. Both were captured through an 80mm refractor.
These nebulae are created when radiation from a hot, young star ionises neutral hydrogen nearby. When the electrons recombine with the hydrogen a very particular photon (corresponding to red light) is emitted. If the star was surrounded by a uniformly dense hydrogen cloud then the resulting nebula would be spherical, with the boundary of the nebula being the place where ionisations and recombinations balance. That's nearly the case for NGC280 above! But hydrogen clouds aren't necessarily distributed so perfectly around stars. In the picture of NGC1499 the nebula is created by the bright star near the bottom of the picture. The hydrogen cloud is clearly some distance from the star.
Hydrogen exists in several forms throughout the Milky Way. Clouds of hydrogen atoms are called HI (H-one!) regions. These ionised nebulae are called HII regions (not to be confused with H2 regions of molecular hydrogen).
I always enjoy getting pictures of these fantastic objects but the astrophysics course is adding a new layer of appreciation to what I'm doing.
Dr Adrian Jannetta
Guitar strummin' explorer of the universe. Mild mannered maths teacher by day and astronomer by night.