Podcaster: Ralph & Paul
Title : Awesome Astronomy’s May Sky Guide
Organization: Awesome Astronomy
Link : www.awesomeastronomy.com
Description: What to look out, and up, for in May.
This month we take a look at the constellation Ursa Major for the beginners guide – we’ll point you in the direction of an unaided eye binary star and a few of the brightest galaxies in the entire northern hemisphere sky.
Next we round up the planets that are visible in May: Mercury (early in the month), Venus, Jupiter & Saturn later on. We take a look at Comet Lovejoy as it’s still visible in small telescopes, and the Lyrids in the low eastern morning sky. For our deep sky challenge we take you on a tour of Hercules’ magnificent globular clusters and a couple of overlooked galaxies.
For those in the Southern Hemisphere, 365 Days of Astronomy also play Alice Enevoldsen’s What’s Up Tonight, Southern Skies Edition each month.
Bio: Awesome Astronomy is the show for anyone and everyone who has even the slightest interest in astronomy and science.
Join Ralph & Paul twice each month, for informative and fun astronomy programs telling you what to look out (and up) for every month. You can be guaranteed a passion for astronomy, simple explanations of complex and fundamental topics, space and science news, absorbing interviews with astronomers who make the news and listeners’ astronomy questions answered
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. We still need sponsors for many days in 2015, so please consider sponsoring a day or two. Just click on the “Donate” button on the lower left side of this webpage, or contact us at signup@365daysofastronomy.org.
Transcript:
Paul: May, the last proper month of nighttime astronomy season in the northern hemisphere and while we must never write off the summer months, for those in the more northerly latitudes we never get beyond astronomical twilight after 23rd May, the sky never quite gets entirely dark and we don’t achieve a separation between the end and start of astronomical twilight until the 22nd July. But don’t pack away your scope just yet because we still have 23 nights of dark skies left and objects a plenty to explore.
But before we look at that, what have you got lined up for the beginners in March Ralph
Ralph: Thanks Paul. For the beginners this month, we’re going to take a look at the constellation of Ursa Major or the Great Bear. Looking north it’s the unmistakable constellation above the pole star familiar for looking like a saucepan or a plough – well the bulk of it is but there’s a lot more stars that make up the Ursa Major constellation than just the Plough asterism
This time of year Ursa Major is nice and high in the sky so three big and bright galaxies put themselves on offer for us to enjoy in 4” or larger telescopes. But before we talk about those galaxies, we’ve got a simple binary star to look for that you don’t even need a telescope for – or even binoculars, because this double star can be seen with the unaided eye in the handle of the plough. If you’re looking north this month the Plough;s handle should be pointing upward above the bowl. Look for the kink in the plough’s handle and you should see that it’s not one star but two very close to one another. These stars are called Mizar & Alcor and legend has it that Arabic armies centuries ago used these stars as a test of good eyesight – if you saw two stars, your eyesight was good. I suspect the separation of the stars has grown over the years or people had particularly bad eyesight back then because I don’t know anyone with remotely good eyesight that can’t see them both without binoculars or a telescope. They’re actually part of a six star system all gravitationally bound but you’ll only see two with the naked eye, though you can split Mizar with a telescope into two white stars, taking the visual count up to three.
Now, let’s stuck into those galaxies. Draw a line between Alkaid and Cor Caroli in the neighboring constellation Canes Venatici (to the right of Ursa Major). And about a quarter of the way along that line and roughly half a degree above that point, sits a truly unique wonder for amateur astronomers, Messier 51, The Whirlpool Galaxy. This was the object that I was desperate to see with my own eyes when I first got a telescope and in images you can clearly see a face-on spiral galaxy devouring another smaller galaxy that strayed too close. The cores of these galaxies are visible in a 4” scope but the view through an 8” scope will blow your mind. And where else can you see something as awe inspiring as two galaxies colliding with your own eyes from your own garden? Technically, it’s in the constellation of Canes Venatici, but being so close to Alkaid in Ursa Major, who’s going to quibble.
Next, you want to move up the Big Dipper to the upper left star in the bowl, Phad or Phecda. Draw a line down from that star to the last star in the bowl, Dubhe. Continue that line for the same distance and you get a two for one, because that’s where you can see a spiral galaxy called M81 and an edge on spiral galaxy, M82, both within the same field of view of a low power eyepiece. Gravitational interactions between the two galaxies set off rapid star-formation in M82 and these should both be very easy to spot after looking at the dimmer Whirlpool Galaxy.
Also in Ursa Major is the Pinwheel Galaxy, M101, but this is quite difficult to spot as it’s got a low surface brightness. But if you feel adventurous, draw a line between the upper left star in the bowl, Phad, through the double star Alcor & Mizar, for about half that distance again, and that’s where this beautiful face on spiral galaxy, M101, sits. It not an easy one but worth a go – especially if you have a 6” scope or larger. Paul?
Paul: Thanks Ralph, now let’s take a look at our little corner of the galaxy and see what kind of show the solar system is putting on for us this month.
When the evening is finally dark after 10.30 then you will find three bright planets across the southern sky, with Venus over in the west sitting in the horns of Taurus and moving through the month to sit between the gemini twins, Jupiter to the south west in Cancer and popping over the horizon in the east will be Saturn in the claws of Scorpius. The best of these will be Jupiter which will still be at a good height for observation but will set just after 1am by the end of the month.
You will get longer with Saturn as the ring world doesn’t set until… but as is the case for a a good few years yet Saturn is low in the sky and unless you have a low, pollution free southern horizon you will be fighting murky turbulent air and tall objects for a good view. The fight will be worth it though as the rings are very well presented at the moment with the rings almost visible the entire way around the planet.
In the first two weeks of the month you may be able to get a brief glimpse of Mercury after the Sun sets as it quickly pulls away then falls back towards the sun. It will be very low and in a bright sky, so this will be a difficult challenge, around the 7th of May will be the best time to have a look. The observant might catch Mercury next to M45 in the evening sky just after dawn on the 1st of the month, this will be a good target for binoculars and small telescopes.
The Moon this month starts almost at full and is full on the 4th moving the last quarter on the 11th, New moon on the 18th and first quarter on the 25th.
We still have Comet Lovejoy which has been one of the great surprises of the last winter will still be gracing the skies and it will be passing by Polaris through May, being closest at the end of the month on the 28th and 29th. Lovejoy is fading but might still be visible in good binoculars.
I will mention the Eta Aquarids meteor shower which peaks on the 6th. Now this is really a southern hemisphere event but it is visible in the morning in the north so if you are up before dawn doo look over to the east and have a look.
For our deep sky tour this month we are going to look at the constellation of Hercules. This famous but not obvious grouping of stars is one many struggle to locate immediately and it is easy to locate several keystones of four stars. If you form a triangle of bright stars with Alkaid at the end of the Plough, Arcturus in Bootes and Vega in Lyra then you should find Hercules in the centre of that grouping. Around the keystone and you should be able to locate the arms and legs of the greek hero. In Hercules you will find two of the best northern hemisphere globular clusters, the great cluster M13 which at mag 6 is naked eye visible in a good sky and the smaller and fainter but no less beautiful M92.
M13 should be easy to locate and can be found on the side of the keystone nearest Alkiad and Arcturus. If you look below the star Eta Herculis you should find a fuzzy star in your finderscope. A good challenge is to look for galaxy NGC6207 just 27 arc minutes away to the north east, a treat that is often overlooked in the dazzling glare of the great globular cluster and easily visible in medium scopes at magnitude 12.
M92 is slightly harder locate as it is outside the shape of the main constellation. On the northern side of the keystone if you make an almost equilateral triangle that leans slightly towards Vega you should find it. This appears smaller than M13 but has a bright core and is one of the oldest objects we can see in the sky, the stars appear to have an age just short of the age of the universe. Both are collections of ancient stars orbiting beyond the galactic disc at around 25-26000 light years distant and are prime examples of this type of object.
A fainter globular in hercules is ngc6229 which at 100000 light years is also 4 times more distant. It has a compact bright core but overall 6229 is mag 9.4 and a real challenge to find. Look for Magnitude 4.8 double star 52 herculis which can be located by drawing a line up the keystone through Eta Herculis from Zeta Herculis and then extending that line the same distance north towards polaris. You should find 6229 near 52 on the same line.
Ngc6210 is a nice planetary nebula visible in medium scopes. 4000 light years distant it will appear as a blue green elliptical disc. You can find it in the bottom half of the constellation in the sparse area between Hercules’ arms (remember our poor hero is upsidedown. If you locate Beta Herculis and then move into this area and find the one brightish star between the arms 51 Herculis, draw a line between them 6210 is located on this line.
So all that remains is to wish you happy hunting and clear skies.
End of podcast:
365 Days of Astronomy
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