Jun 1 2012 By Ninian Boyle
You need to stay up late to get dark skies this month and they are short lived, but don't let that stop you from going out and having a look around at the wonders of the heavens.
So the planet Venus is going to transit the face of the Sun. So what? Well to astronomers the world over this is a big event. It happens once every 105.5 or 121.5 years and then has a gap of 8 years. Why it happens like this is a little complex, but suffice it to say, because of its rarity, it is an interesting event.
We are now in the season of Noctilucent Clouds. The best time to try and see these, if there are any to see that is, will be about an hour after sunset or before sunrise. You'll need clear skies and look towards the northern horizon. They have a distinctive look, having an almost 'electric blue' colour to them and they often occur in herring bone patterns. Check out my blog for more information on these and what you can expect to see.
We have two planets left to view in the evening skies, that of Mars and Saturn. We are moving away quite rapidly from Mars now and it can be disappointing through a telescope due to it showing a very small disc. However, with patient observing through a telescope, it may still show a few dark markings and a polar cap.
The Sun is very active now and is heading towards 'Solar Max' in 2013. You need to take great care if you plan to observe our nearest star and this includes if you plan to see the Transit of Venus across its face. Sunspot counts are rising and if you have access to a hydrogen-alpha solar telescope you will be able to see lots of activity including prominences and filaments.
The constellations and asterisms of Summer are now coming well into view, including the 'Summer Triangle', the 'Keystone' asterism in the constellation of Hercules and the 'Northern Cross' of Cygnus the Swan. Asterisms are a great way of navigating your way around the sky. If you would like to know more about this, then I'll be describing how you can find out how you can use them, next month.
The Moon This Month
We see a Full Moon on the 4th. The Full Moon in June is otherwise known as the Rose Moon, Flower Moon, Strawberry Moon or the Honey Moon. Whatever you may like to call it, it certainly looks impressive. The Full Moon though, is not the best time to go exploring our nearest neighbour in space with a telescope or binoculars, as there is little shadow to make the features such as craters, stand out.
The Planets This Month
Without a doubt, Venus is the main performer this month as it transits the Sun on 5/6th of June. There's more about this a little later...
Mars is still visible in the evening sky in the constellation of Leo. You can recognise it by its distinctive orangey colour. We are moving away from the planet at the moment and so it seems to becoming ever smaller in our telescopes. Because of the increased distance, it is also becoming dimmer, fading from magnitude 0.5 to 0.8. This doesn't sound much but it is noticeable.
Jupiter is lost in the glare of the Sun's light at the beginning of the month, but at the end of June you may be able to spot it shortly before sunrise low in the north-east in the constellation of Taurus the Bull. You should also be able to see the planet Venus to the south-east of Jupiter. The best time to see this conjunction is around 4:00am BST. The planets are at their closest on the 30th.
Saturn is the best displayed of all the planets this month. It lies not far from the bright star 'Spica' in Virgo the Virgin and is to be found in the south-western sky around 23:00 BST. Spica is a very brilliant white coloured star, whereas Saturn has a yellowish tinge. Although this planet too, is past its best, it is still a glorious sight in a small telescope as you can see the rings clearly and a moderate magnification should even show some detail in the clouds which encircle the planet.
The planet Uranus at the end of June is slowly starting to come back into view. You can find it rising due east around 01:30 BST in the constellation of Pisces the Fish. It's tiny disc is discernable in a small telescope and has a slightly greenish tinge.
The elusive planet Mercury is visible from the 10th of the month. You will need a clear north-western horizon though, if you have any hope of seeing it. If you are going to use binoculars to 'sweep' for the tiny planet, make sure that the Sun has fully set before you scan the horizon!
The Transit of Venus
Due to a quirk of geometry, the planet Venus every now and then appears to cross the face of the Sun from our point of view here on Earth.
What's so interesting about this? Well it only occurs once in over 100 years and then again 8 years later and then once again we have a very long wait before the angles are right for us to see it again. The last Transit was in 2004 and so, this is going to be the last chance we will have to see it in our lifetimes as it won't happen again for another 105.5 years! This will be visible on the 5/6th June depending where you are on the globe.
The best places to see it will be from Australia and New Zealand. You will be able to see it from most of the USA when Venus will be seen transiting the Sun during sunset. But what about Europe and especially the UK? Here, the further north and east you are, the more chance you'll have and the more you will see of it, as the Transit will be in progress at sunrise. Don't let this put you off trying to observe this once in a lifetime event though. If you have a clear horizon, the coast may give you a good opportunity here; then you should be able to see around 20 minutes of the Transit depending on where you are.
You will need safe solar filters for the whole event! Do not attempt to look at the Sun's disc with any unfiltered optics, including camera lenses. Even though the Sun may appear much dimmer at sunrise it is still potentially very dangerous, so please treat it with the utmost respect. Eclipse shades may serve you well if you don't have access to a filtered telescope or binoculars. There are lots of website and other places on the Internet which will provide you with information about the Transit and how to view it safely, including that of my ownwww.astronomyknowhow.com/blog So do drop by and have a look.
So let's hope for good weather and a clear sky at dawn on the 6th June. Good luck and stay safe!
Deep Sky Highlights of June
The nights of June are very short and from mid-northern latitudes we never get true darkness. However, there are still plenty of objects worth observing if you have binoculars, or a small telescope...
There are quite a few globular star clusters to be found in the June skies. If you have a good view to the south, the constellation of Scorpius the Scorpion contains the bright Messier 4 (M4) quite near to the star Antares, the red Super-Giant star at the base of the claws of the Scorpion. M4 is obvious in binoculars and quite spectacular in a small telescope. It is due south at midnight in the middle of the month.
To the north and slightly west of M4 is M80. This is another bright globular cluster, although it is fainter than M4. You can find it about half way along the northern-most claw from Antares. Again this looks impressive in a small telescope.
If you move east from Scorpius and into the constellation of Sagittarius the Archer, I would encourage you to just sweep around this region with binoculars because it is awash with star clusters and nebulae. The reason for this is that here, we are looking towards the heart of our galaxy the Milky Way. So there is an abundance of material to view. In fact, there are so many stars, and so much gas and dust, it blocks our view of the centre of our galaxy. Fortunately, we can probe it in greater depth using radio telescopes and this is how we know that there is a super-massive black hole at the centre of our galaxy.
Heading north-east from Sagittarius you will find the constellation of Scutum the Shield. The stars in this group are not particularly bright, but it does contain a bright and attractive open star cluster Messier 11 (M11) otherwise known as the 'Wild Duck' cluster. This is an attractive sight in binoculars and in a small telescope you should be able to resolve many of the stars. See if you agree it looks like a flight of ducks...
One of my personal favourite star clusters, although strictly speaking, it isn't really a 'cluster', is known as Brocchi's Cluster or more commonly, the 'Coathanger'. You can find it in the constellation of Vulpecula the Fox, a few degrees to the south-west of the double star Albireo in Cygnus the Swan, rising in the east in mid-evening. It looks great in binoculars and is shaped amusingly like a coathanger! As I said, it isn't a true cluster, but just a line of sight effect with these stars. It's very appealing, nonetheless.
If you are on Facebook, please come and be 'fan' of my page 'Astronomy Know How with Ninian Boyle'. I'm planning to use it for lots of free information and tips on how to observe the night sky and also post up interesting events as they are set up. It will mean that you'll be the first to know about really useful things connected to your hobby, so join me on facebook
Oh! and you can follow me on Twitter too www.twitter.com/astroknowhow