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. We start with the constellation of Hercules in our beginner’s and young observer’s guide, and end it with a few deep sky challenges for the more advanced amateurs to hunt down. Next up is the moon and our round up of the craters and interesting lunar features you can explore with a small telescope. Mars, Saturn & Jupiter feature in the planetary round up for Northern Hemisphere observers. We have the Eta Aquarids meteor shower courtesy of Halley’s Comet at the beginning of the month and a possible meteor storm from Comet LINEAR towards the end of May. We then finish off with a galaxy hunt around the Virgo Cluster.
Bio: Awesome Astronomy is the show for anyone and everyone who has even the slightest interest in astronomy and science.
Join Ralph & Paul at the beginning of each month, for an informative and fun astronomy programme 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 and listeners’ astronomy questions answered.
As both presenters have been accused of being a little skeptical in the past, you can also expect everything to be frivolous but fact-based
Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by — no one. We still need sponsors for many days in 2014, 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: Flowers in the fields, trees in leaf, the warmer, lighter evenings, it can only mean we are now in the heart of Spring and heading through May. While dark sky enthusiasts will begin to really notice the shorter nights, the skies we will be viewing this month are filled with some real jewels of astronomy, including the return of some summer favourites, a planetary opposition and a possible new meteor shower towards the end of the month.
Ralph: For the beginners and young astronomers this month we’re looking toward the Hero of Roman mythology, Hercules. Already positioned well above 20 degrees in altitude by nightfall on the 1st of the month, it’ll be higher than Jupiter was at this year’s loftiest by month’s end.
Hercules doesn’t have any stars above magnitude 2.8 so it doesn’t glow like The Plough asterism in Ursa Major or the Orion constellation. But if you look out to the south east you’ll easily see the squashed square of stars that make up the famous Keystone asterism – an asterism being a grouping of stars that make up a pattern within constellations or shared between constellations.
Now, just over half way between a line drawn from the bright yellow star Arcturus in Bootes and bluey white Vega in Lyra, sits this Keystone, itself made up of four stars: magnitude 3.5 eta Herculis at the very top, the noticeably brighter zeta Herculis to its right at magnitude 2.9, epsilon Herculis at magnitude 3.9 at the very bottom of the quartet and the final star pi Herculis on the left at magnitude 3.2
Apart from being the first month of the year that Hercules rises to a favourable altitude in the sky, May is also a good time to be gazing in that direction because between 19th May and 19th June the Earth passes through debris left by the implausibly named Comet Schwassman-Wachman 3 with Hercules being the radiant or the point where the Earth directly moves into the debris giving us between 1 and 60 meteors per hour at it’s peak on 9th June.
But on to the deep sky objects: Hercules is home to two of the finest globular clusters and a nice simple double star that are all easily observed in amateur scopes.
Firstly, we start with one of the wonders of the entire northern hemisphere, Messier 13 or the Great Globular Cluster in Hercules. It’s also one of the easiest deep sky objects to locate. Find the Keystone Asterism scan the line between zeta and eta Herculis with low magnification, and about two thirds the way along, you see a small dense smudge. Increase the magnification and you’ll see dozens of individual stars, even in a 5” scope. This is a gravitationally bound ball of more than a quarter of a million stars 145 light years across in a halo around our galaxy 25,000 light years away.
Another globular cluster sitting in this halo around 26,000 light years away is Messier 92. This is a smaller cluster but still bright enough to be on the boundary of naked eye visibility in a dark site. To find M92, take a low power eyepiece again and scan along a line between eta Herculis and iota Herculis in the foot of the Hero (note that Hercules is on his head as we observe him) and, again about two thirds of the way to iota, sits this lovely cluster.
Finally, end with an easy grab in the constellation’s second brightest star Rasalgethi – so far from the body of Herculies that it almost appears to be in the neighbouring constellation Ophiuchus. Increase the magnification on this star to split it into two components of a red giant and a yellow companion star 360 light years away.
Paul: Now lets take a look at those planets and top spot has to go to the ring world saturn which reaches oppositon on the 10th. For northern observers Saturn is not at it’s a best and will not be in higher clearer skies for many years but the view is still incredible and by way of compensation the rings are very well placed this apparition. Look out for the brighter moons such as Tethys, Dione, Rhea, Iapetus, Mimas, Enceladus and of course Titan, the only moon with an atmosphere. Saturn is currently in Libra and will be shining away at magnitude 0.2.
This is a good month for Mercury with that planet reaching it’s greatest eastern elongation on the 25th. Start looking northwest from around the 7th of may for your best chance to see this elusive planet in the dusk sky. It will fade as the month goes on starting at magnitude -1.1 and ending at 0.5.
The King is still holding on but is well past it’s best now, but Jupiter is always worth a look and particularly this year as even now it starts the evening quite high in the sky before fighting with the glow of sunset. Still in Gemini and will be blazing away at -1.8, still making it one of the brightest objects in the sky.
Mars is past opposition and fades quickly through the month, beginning May at -1.2 magnitude and ending at -0.5. Currently sitting in Virgo, look out for surface details such as Syrtis Major and the polar ice cap.
Venus is still the morning star and will be for the next little while, sitting low in the predawn sky an hour before sunrise and blazing away at -3.9.
Now for the selenologists out there, or those DSO hunters wanting to avoid, it’s time to look at what the moon is doing in May
We begin with the moon just past new at the start of the month and reaching first quarter on 7th at 03.15 UT. We reach full on the 14th at 19.16 UT, last quarter on the 21st at 12.59 UT and the skies are dark once more in the last week of the month as we reach new moon on the 28th at 18.04 UT.
On it’s journey through the night sky we get to see some nice encounters and start the moth near Jupiter on the nights of the 3rd and 4th. Regulus in Leo is near the moon on the nights of the 7th and 8th, on the 11th its sits between Mars and the star Spica. Saturn is nearby on the nights of the 13th and 14th and on the 15th the moon sits right above Antares. Look out for the always stunning pairing of the moon and venus in the dawn sky on the mornings of the 25th and 26th. Jupiter gets another bite of the lunar cherry on the evening of the last day of the month.
There are some interesting libration craters to look out for around the limb this month, starting with the North of the moon we have Crater Hayn on the 3rd and de sitter on the 6th, while at the middle of the month the libration favours the south west of the moon with crater inghirami on the 16th.
Now May might be a very good month for meteors this year. We start with the Eta Aqurids, a shower based on the debris of Halleys comet. The peak is on the 5th/6th and is best seen after 2am when the moon sets. This shower has a Zenithal Hourly Rate of about 30 so is worth a look.
the exciting meteor news though is for the night of the 23rd/24th when we have not just a shower but a potential storm as we hit the debris trail of Comet LINEAR which was in discovered in 2004. Earth this year hits it’s debris trail square on and we are looking at a possible ZHR of 100-400 and a potential for 1000 per hour after midnight. Definately one to stay up for.
For our deep sky challenge this month we are looking at the the Virgo cluster of galaxies that can be found in the constellations of Virgo and Coma Berenices. Now Virgo is a pretty indistinct constellation that is best found by looking at the area between the stars Denebola in Leo, Arcturus in Bootes and Spica in Virgo, now in the middle of this triangle of stars is the Virgo cluster and a good star to pick out as a signpost to the cluster is vindemiatrix which sits near the centre of that triangle slightly closer to Arcturus and Denebola.
There are a mryiad of galaxies to look out here and those with bigger scopes will be able to lose themselves in leaping from one the other but here we will pick out three highlights. First of moving south east of Vindemiatrix we have M49, a large elliptical galaxy that was the first discovered of the virgo cluster. Despite being 49 million light years away it is very bright and easily found, look out for surrounding galaxies such NGC 4469, 4526 and 4535.
Closer and to the west of the star we have five Messier galaxies is close proximity, M60 a bright elliptical 55 million light years away, M59 another elliptical at a similar distance, M58 a face on barred spiral which at 68 million light years was for a long time the furthest observed object. M89 and M90 sit close to each other, M89 being unusual as it is thought to be an elliptical galaxy that is almost a perfect sphere. M90 is a large and bright spiral galaxy.
Moving to the Northwest from Vindemiatrix we get to perhaps the jewel in the crown of the Virgo super cluster, Markarian’s chain. Here you will find a spectacular line of galaxies that start in the west with M84 and 86 and flow away to the northeast with NGC4438 and 4435, then three fainter galaxies in the form of 4461, 4473 and 4477. After a gap you will find the large and bright M88 and not to distant from there M91. To the south of the cain do look out for the monster that is M87, one of the largest galaxies known and certainly one of the largest near our own, which is utterly dwarfed by this massive elliptical.
Have fun galaxy hunting and as always do report and post your observation and images on our facebook, twitter and flickr groups.
End of podcast:
365 Days of Astronomy
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