Podcaster: Ralph & Paul
Title : Awesome Astronomy’s April Sky Guide
Organization: Awesome Astronomy
Link : www.awesomeastronomy.com
Description:What to look out, and up, for in April.
This month we look in the direction of Leo the Lion for the beginners guide – taking a look at the bright binary stars and a very special grouping of entire galaxies to observe in our spring skies.
Next we round up the planets that are visible in March 2015: Jupiter, Venus, Saturn and the return of Mercury. April brings us some nice lunar conjunctions and a well timed Lyrid meteor shower. And for our deep sky challenge we take you on a galaxy tour of Virgo and Coma Berenices.
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
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Transcript:
Paul: April is here and the night skies are getting noticeably shorter and brighter with every day that passes, but that does mean the evenings are warmer and those core chilling nights fighting the frost on your scope are behind us as are the winter constellations which set soon after the Sun and leave us with a spring sky full of galaxies as our sky stares into the Virgo supercluster. We have a good meteor shower to look forward to and perhaps our last good look at Jupiter in this mutual event season.
Ralph: Well this month we’re going to take a look at the constellation of Leo the Lion for our beginner’s guide. Much as Orion dominates the southern portion of the sky in winter, Leo, another large and unmistakable constellation dominates in Spring. And as Spring’s often called galaxy season, you won’t be surprised to learn that we’re going galaxy hunting this month.
From 10pm at the beginning of the month and as soon as it’s dark by the month’s end, Leo will be nice and high in the south. It’s really easy to pick out as it really does look like a crouching lion and has three stars brighter than magnitude 2.2 – Algeiba in Leo’s neck, Denebola at magnitude 2.1 in the lion’s tail and bright magnitude 1.4 Regulus in Leo’s front paw.
And we’ll start with that first star Algieba because this giant star not only has a planet twice the size of Jupiter in its system, but also a companion star. You can’t see the planet from Earth but a modest telescope will be able to split Algieba into two nice colour contrasting stars of orange & yellow. So give that a go.
Moving down the lion’s chest, we have the brightest star in Leo, Alpha Leonis, or Regulus. This is another binary star that can be split with any sized telescope at high magnification. The companion star’s only magnitude 8 but with an 8” scope or larger, you might even tease out a second yellow companion to Regulus
Moving onto Denebola in Leo’s tail. Denebola’s the 2nd brightest star in Leo. It has 75% more mass than our sun and it’s relatively young at only 400 million years old. For contrast, our sun is four and a half billion years old. Denebola rotates incredibly fast and, if you could see it close up, you’d see it bulges at its equator – similar to Jupiter.
Now, earlier I promised you galaxies and the the cream of the crop in this part of the sky is a three for one offer known as the Leo Triplet that sits below the hind legs of the Lion
Here you’ll see three smudges of light in a medium sized telescope under low magnification, especially in dark skies. If you use a 5” or larger scope you’ll see that these are clearly individual galaxies. It may be that you only see the brighter two at first, but spend a while getting used to this eyepiece view and you should find the third galaxy with averted vision – averted vision means looking to the side of the object you want to see to let your more light receptive peripheral vision reveal it.
In the Leo Triplet, the first of the brighter pair, Messier 65, is magnitude 10.3 and shows us a spiral galaxy tilted away from us.
Next to it, Messier 66 is brighter at magnitude 8.9 and another spiral galaxy, this time with a more favourable tilt, so large amatuer scopes may even tease out the spiral arms & dust lanes, but even smaller scopes should see a nice bright core of billions of suns.
The final companion in the Leo Triplet is Sarah’s Galaxy, NGC 3628, which is the dimmest of the three at magnitude 14.8 and it’s a good test of your averted vision ability. But seeing all three, 35 million light years away, in the field of view of the same eyepiece really is a treat.
Paul: Now it’s time to have a look at what is happening in our solar neighbourhood this month.
Planets are a little thin on the ground in April, Jupiter is still King and dominating the evening sky from Cancer, while after sunset we have Venus which is moving further east as the month goes on and will be In Taurus below the pleiades around the middle of the month, ideally placed between the 10th and 12th. As we reach the end of the month look out for Mercury making a return to evening skies and in the last couple of days of the month Mercury will have a close encounter with M45 as well.
Saturn is still an object for the night owls and is best placed well after midnight in Scorpius. The rings though look spectacular this apparition and are almost visible behind the planet as well so it is well worth staying up for and getting a view.
Mars may just be visible in the glow of sunset while Uranus and Neptune are not visible this month.
After last months eclipse the moon has a quieter month ahead of it, with perhaps an encounter with aldebaran on the night of the 21st. For those in the north of the UK, such as the shetlands you will see a full occultation. The moon begins the month almost full which it reaches on the 4th at , last quarter is at on the 12th, new moon is achieved at on the 18th and first quarter is reached at on the 25th.
April is of course time for one of the better meteor showers in the calendar the lyrids which occurs from the 16th and peaks on the night of the 22nd/23rd which the observant will immediately realise shortly after the new moon so this hopefully will be a vintage year for viewing the debris of Comet Thatcher. ZHR is around 20 an hour and the radiant is in Lyra.
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 myriad 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 chain 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.
End of podcast:
365 Days of Astronomy
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