Northern Hemisphere
Ian Morison tells us what we can see in the Northern Hemisphere night sky during March 2018.
Jupiter.Jupiter rises just before midnight at the beginning of the month and about one hour earlier by month's end. Initially it has a 39 arc second disk, shining at a magnitude of -2.2 but as the month progresses, its apparent diameter increases to 42.5 arc seconds and it brightens to magnitude -2.4. Jupiter will transit before dawn and so will enable the giant planet to be seen with the equatorial bands, sometimes the Great (but reducing in size) Red Spot and up to four of its Gallilean moons visible in a small telescope. Sadly, Jupiter, lying in Libra during the month, is heading towards the southern part of the ecliptic and will only have an elevation of ~20 degrees when crossing the meridian. Atmospheric dispersion will thus hinder our view and it might be worth considering purchasing the ZWO Atmospheric Dispersion Corrector to counteract its effects.
Saturn.Saturn, at the start of its new apparition, rises at around 3 am at the start of the month and just after 2 am at its end. With an angular size of ~16.3 arc seconds it climbs higher before dawn and so becomes easier to spot as the month progresses. Its brightness increases from +0.6 to +0.5 magnitudes during the month. The rings were at their widest a few months ago and are still, at 26 degrees to the line of sight, well open. Saturn, lying in Sagittarius, is just 3 degrees above the topmost star of the 'teapot'. Sadly, even when at opposition later in the year it will only reach an elevation of just over 15 degrees above the horizon when crossing the meridian. Atmospheric dispersion will thus greatly hinder our view and it might be worth considering purchasing the ZWO Atmospheric Dispersion Corrector to counteract its effects.
Mercury.Mercury gives us its best evening apparition this month when it reaches its peak height above the western horizon on March 15th when, at greatest elongation, it lies some 18 degrees west of the Sun. However, by this time its magnitude has dropped from -1.3 at the beginning of March to -0.4 magnitudes. Its magnitude continues to fall, dropping to +0.9 by 20th and soon after will be lost in the Sun's glare. Mercury flirts with Venus during the month as detailed in the highlights.
Mars.Mars starts the month moving quicky eastwards in Ophiuchus moving into Sagittarius on the 12th of the month as it moves towards Saturn. Now a morning object, it rises at around 2 am at the start of the month. During the month, Mars has a magnitude which increases from +0.8 to +0.3 and an angular size of just 7, increasing to 8.5, arc seconds so it will be hard to spot details on its salmon-pink surface. It will only reach an elevation of ~14 degrees before dawn at the start of the month and just 12 degrees by month's end.
Venus. Venus, seen low in the west after sunset shines at magnitude -3.9 all month with an angular size of ~10.3 arc seconds. Venus rises a little higher in the sky as March progresses, initially setting around one hour after the Sun but increasing to an hour and a half by month's end. It has two near conjunctions with Mercury as described in the highlights above.
Highlights
March 2nd to 4th after sunset: Venus and Mercury within 1.3 degrees of each other.After sunset on these three evenings and given a clear sky and a low western horizon, you should be able to spot Venus and Mercury. Their closest is on the 3rd when they are just 1.1 degrees apart. Binoculars might be needed to penetrate the skys residual brightness, but please do not use them until after the Sun has set. [Note: The sky brightness has been reduced in the chart.]
March 10th/11th before dawn: Saturn, Mars and a waning Moon. Mars below a waning Moon If clear before dawn on the 10th and 11th, looking just east of south, one should see a waning crescent Moon lying to the upper left of Mars on the 10th and Saturn on the 11th.
March 19th after sunset: Venus, Mercury and a very thin crescent Moon.Looking West after sunset on the 19th and given a very low western horizon, one might be able to spot Venus near Mercury which is close to maximum elongation from the Sun. A very thin crescent Moon, just two days after new, will be seen up to their left. Binoculars may well be needed, but please do not use them before the Sun has set. A tough observing challenge! [Note: the sky brightness has been reduced in the chart.]
March 23rd evening: The Moon in the Hyades Cluster.In the evening of the 23rd of the month, the Moon, coming towards first quarter, will lie within the Hyades cluster. After it has set from the UK it will occult Aldebaran which is a red giant star lying between our solar system and the cluster.
March 8th and 24th: The Alpine Valley.These are two good nights to observe an interesting feature on the Moon if you have a small telescope. Close to the limb is the Appenine mountain chain that marks the edge of Mare Imbrium. Towards the upper end you should see the cleft across them called the Alpine valley. It is about 7 miles wide and 79 miles long. As shown in the image is a thin rill runs along its length which is quite a challenge to observe. The dark crater Plato will also be visible nearby. You may also see the shadow cast by the mountain Mons Piton lying not far away in Mare Imbrium. This is a very interesting region of the Moon!
This month we welcome two new presenters, Gabriela Perez and Jasmine Chan-Hyams who tell us what we can see in the Southern Hemisphere night sky during March 2018.
Introduction.I'm Gaby, I work at Space Place at the Carter Observatory, in Wellington New Zealand as a telescope operator. I've been staring at the Southern Skies for most of my life. As a child I saw the fully mapped-out globe and I became fascinated with space, ever since I have wanted to explore the universe beyond. Now I bring the universe to me (mostly through collecting its light) with my eyes, a pair of binoculars or a telescope.
And I'm Jasmine, I am a PhD Biotech student at Victoria University of Wellington. But who I am is a scientist, a star-gazer and a story-teller. We wish a fond farewell to Claire who has contributed so much to this podcast over the years. Thank you for teaching me about treasuring that moment of awe when you share a wonder of the universe with someone who has never seen anything like it before. You will be sorely missed at Space Place and we wish you all the best in your new job!
Looking up into the night skies is one of the true delights of living in the southern hemisphere; especially here in Aotearoa, New Zealand where it is easy to get away from the bright city lights and where we a get a broader and brighter view of the Milky Way.
Early in the month of March we can look forward to gazing upon many star studded greek heroes and mythical creatures. We can use constellations as guideposts to find deep sky objects including beautiful nebulae and special features of our southern skies.
The region around Orion. Our journey begins with the Greek constellation Orion, who appears in the skies after full dark in north-north west for the month of March. For many of us finding the three bright stars that form Orion's belt were probably the first thing you could proudly identify as a child. These three stars are 2nd magnitude stars. You can also see with the naked eye Betelgeuse, located in Orion's armpit; a red supergiant hundreds of times larger than our sun. Yet the brightest star of this constellation is Rigel - a blue star at Orion's ankle. Blue stars are the hottest kind of stars you'll find in the night skies while red stars are cooler and burning up the last of their heat energy. Just below his belt you'll find the Orion Emission Nebula (M42)- a huge star forming cloud - more than two widths of our moon across, it lies about 1500 light years away. With the naked eye it appears as a diffuse cloudy patch. Through a telescope you can see the clouds of dust and gas, lit up by the baby stars they are forming.
From Orion's belt it's just a star jump to the right and up to find Sirius, the brightest star in our skies. Sirius is seriously bright at about 20 times brighter than our sun and is only 8.6 lya. Sirius is part of the Canis Major constellation - one of the two dog companions that accompany the hunter Orion. Below Canis Major you can look for the two stars that form Canis Minor. The star Procyon, in Canis Minor, forms a triangle with the 1st magnitude stars Sirius and Betelgeuse.
Within this "southern triangle" you can look for the Monoceros unicorn constellation - home to the gorgeous Rosette nebula. This nebula has a beautiful carnation pick colouring and can be seen with binoculars in the part of the constellation closest to Betelgeuse.
Neighboring Orion is the zodiac constellation Taurus the Bull. Taurus and his fiery eye, the red giant Aldebaran, can be found low in our Northern-Western sky after sunset where we can easily make out his V shaped horns. Near his shoulder lies the Pleiades star cluster. On a clear dark night you can see seven points of light with the naked eye but it is best viewed with a pair of binoculars. The Pleiades is a young cluster of mostly hot blue stars, the big ones that burn up all their fuel quickly -they live fast and die young. These bright blue stars are said to be seven beautiful sisters. You can find the seven sisters sheltering in the shoulder of the bull hiding from Orion's amorous intentions.
Crab Nebula. After you get an eyeful of these blue beauties you can jump down to the Crab Nebula (M1) but you'll want a telescope for this part. M1 was the fist Messier object recorded by famous French astronomer Charles Messier in 1771. To find M1 with your telescope look for Aldebaran first then follow the bull's horn to the end, it will be close to the horizon. Large apertures are needed to make out the filamentous detail. The Crab Nebula is was first viewed more than a 1000 years ago, by ancient Chinese astronomers, who recorded a bright light forming in this area. They witnessed was a supernova - a dying star. At the heart of the Crab Nebula is the pulsar, the skeleton of the dying star. Although we cannot see it with a telescope we can listen to the radio waves it emits as it spins. We can listen to the song of supernova.
You can enjoy looking for Orion, his hunting dogs, Taurus and the unicorn Monoceros throughout the early evenings of March. Now I'll hand over to Gabriela who'll tell us what planets we can see this month and features of the skies to the south.
The Planets - But if you are looking for planets in March, you'll need stay up late. Venus sets shortly after the sun but becomes increasingly visible in our twilight skies towards the end of the month. Jupiter rises in the late evening about midnight in mid-March. This gas giant reflects the light of our sun and outshines Sirius, becoming the brightest object in our night sky after the Moon. For those early risers Mars and Saturn are in the eastern horizon just before dawn. Around the 7th of March the planets will line up quite nicely on either side of the waxing gibbous Moon. On the 21st of March we can observe the Autumn equinox when there night and day will be of equal length.
Constellations and Nebulae - This is probably my favourite time of year to look at the Southern Skies because you can stay out late without either freezing to death or being eaten alive by mosquitoes and the most important objects stay high in the skies for longer. The Full Moon will occur mid-month on the 12th of March. So the beginning and end of March are excellent times to explore the deeper sky objects that you can only see from the southern hemisphere.
Turning to the south horizon we look for the kite shaped Southern Cross constellation Crux. The Crux will be low in our South Eastern sky in early March after sunset. We can use the pointer stars, red-orange Alpha Centauri and blue-white Beta Centauri to identify the true Southern Cross.
As night progresses, the Southern Cross journeys around the southern celestial pole, bringing with it the dark patches stretched out through our view of the Milky Way. Here these patched represents the Giant Moa -a now extinct large flightless bird native to New Zealand. These dark patches are where large interstellar objects, called Dark Nebulas, have blocked out the light from more distant stars - preventing their light reaching us here on Earth. Dark Nebulae are easily seen against the backdrop of the Milky Way as the large concentration of star-light surrounding them lets us see them better. The head of the Moa sits by the Crux, nearby Beta Cruxis and the Jewel Box Cluster. This dark nebula is usually known as the Coalsack nebula. Much like coal itself it could one day ignite as it becomes an active stellar nursery, shining up as one of the brightest sections of our skies.
Following the Moa's ascent, Scorpius rises in the east. In Maori starlore we know it as the legendary fish hook of Maui. Where the Milky Way bulges, next to Scorpius, is Sagittarius A - the Galactic Centre - where we have the brightest view of our own galaxy. From the Galactic Centre we receive intense radio feedback from the super-massive black hole at the centre of our Milky Way.
Using the Southern Cross we can find, Canopus, the second brightest true star in our sky. It is part of the Carina constellation, the keel of Argo Navis. The ship that used to dominate the night sky as the largest constellation. In March it is located above the Crux. In the centre of this constellation is the Great Carina Nebula which houses the giant red dying star Eta Carinae. It once illuminated our night sky as one of the brightest stars for a short period of time after it undertook a massive event known as an imposter supernova. Now this hardy star, encased in the Homunculus Nebula, has faded and can only be seen through a telescope.
The globular star cluster 47 Tucanae will be high in the sky and faintly spotted to the naked eye by the tenth brightest star, the pancake star Achernar (It's spinning so fast it's flattened itself out a bit). Globular clusters are fascinating things. Their structure allows us witness stellar interactions but also allows us to pinpoint the smallest and faintest stars. The large bright stars are at the core while the outer stars are fainter creating a unique and beautifully ordered structure found only in globular clusters.
Magellanic Clouds - We can also look for two of our neighbouring galaxies - the Magellanic Clouds. You can see them without the aid of a telescope. But you will need to get away from the bright city lights on a dark moonless night. These two small irregular dwarf galaxies orbit our Milky Way. The gravitational, pull of our galaxy, warps and distorts them - pulling away clouds of dust and gas and even stars to form the Magellanic Stream. The SMC and LMC are actually connecting by a bridge of neutral helium, suggesting they were once the same object. The Magellanic Clouds are the furthest objects away from home that we can see from our backyards in the southern hemisphere.
G - That's it for us in the month of March. Thanks for tuning in. J - and we wish you all very happy star gazing.