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Listen: https://soundcloud.com/astrophiz/astrophiz187-march-skyguide
Dr Ian Musgrave brings us his March SkyGuide … telling us when, where and what to look for in the evening and morning skies this month.
He also gives us his ‘Tangent’ about ‘Quasi’ Moons.
Also Ian is continuing his ‘Astrophotography Challenge’ where he presents us with an achievable and challenging task to undertake with our cameras.
This month it’s imaging Vesta and learning how to use the free *DeepSkyStacker software
*Note that DeepsSkyStacker is Windows only software … so those like me on Mac platforms might want to join me in trying out the free StarStaX (Mac) software.
EDIT: It seems StarStax is for making star trails,which is exactly what I don’t want!
** or for more experienced ppl, I understand you can install ‘Wine’ on Macs and run Windows applications without having to use an emulator
TRANSCRIPT:
Welcome to the 2024 season of the Astrophiz Podcast.
My name is Brendan O ‘Brien, and first of all, we would like to acknowledge Australia’s first astronomers, the Aboriginal and Torres Strait Islander people, the traditional owners and custodians of Australia … the land we are on.
This episode is produced on Yorta Yorta and Kaurna Country.
And we’d also like you to influence your local politicians to do more to mitigate climate change by moving from fossil fuels to renewable energy sources.
We’re now in our ninth year of production with over 180 fabulous interviews with top scientists for all over the world. Each month we produce two fabulous episodes: On the first of each month, Dr Ian AstroBlog Musgrave gives us his monthly SkyGuide, plus a unique astrophotography challenge.
Then, on the 15th of each month, we publish an interview with a leading astronomer, astrophysicist, space scientist, data scientist. telescope engineer, project manager or particle physicist … and we discover their science journey and rare insights into how they think and conduct their amazing research into exactly how our universe works.
Our audio files and transcripts are available on our website at AstrophizDOTcom and MP3s can be freely streamed from SoundCloud and Apple podcasts … but right now we’re zooming over to Adelaide in South Australia to speak with Ian.
Brendan: Hello Ian …
Ian: Hello Brendan, how are you going?
Brendan: Very well thank you despite the heat … and I hope you cooled down a bit there over in Adelaide.
Ian: We haven’t needed to … just no longer stinking hot in the middle of the night. It’s also makes it worse for astrophotography, of course. It’s nice and warm when you’re wandering out at the Fringe Festival, but when you’re trying to image the moon or the stars or anything the sky dances around like crazy.
Brendan: Well, I’m looking forward to hearing a bit of astrophotography news from you tonight, Ian. Can you tell us? What’s up in the sky for the month of March?
Ian: Okay … well not as much is happening in March as in the previous months … but as usual I’ll start with the moon …. because the moon is of course a guide to planets as well as to the best time to observe the sky …. so let’s start with the moon … March the fourth is last quarter moon so now is a good time to look at the evening sky without the moon about.
March the 10th is the new moon … also very good for feint fuzzy watching.
March 17th is first quarter moon and March the 25th is a full moon … this is another Apogee mini moon like last month and it’s also a very sad penumbral eclipse.
The moon is at Perigee on March the 10th and on Apogee at the March the 24th. Earth is also at Equinox on the 20th so we’re definitely heading into Autumn.
Brendan: Yep
Ian: So let’s move to the evening sky.
Mercury returns to the evening sky this month. Unfortunately unlike the morning sky in the past month it’s hazing the western horizon and never really gets outside of the twilight.
Even on the 25th when it’s furthest from the Sun it’s still deep in the twilight and probably only about a couple of finger widths above the horizon at civil twilighr … So not much joy from Mercury this month. month.
Brendan: Yep …
Ian: Jupiter, which has been dominating the sky for the past few months, is now lowering in the north-western evening sky.
It’s still quite easy to see and will be easy to see all of this month, but it’s going to be a difficult telescopic object as it goes deeper into the twilight as the month goes on.
On the 14th, Jupiter and the Crescent Moon are very close, not fantastically close, but at seven degrees apart, Jupiter and the Crescent Moon will be quite lovely to look at.
Brendan: Cool …
Ian: Now, Uranus has not been playing a big role in our talks, but Jupiter and Uranus are coming closer over the month, and they’ll be closest around about the end of the month … but they’ll be very difficult to see in the twilight. Well, Jupiter won’t be difficult to see but Uranus will be very difficult to see even though it’s just around naked eye visibility you’ll need binoculars to see it in the twilight.
Brendan: Okay.
Ian: By the end of the month Jupiter and Uranus will be about five degrees apart.
Now … let’s go to the morning sky. Venus still remains a beacon in the morning sky but it’s sinking further into the twilight.
It’s probably a nautical twilight object at the beginning of the month but by the end of the month it’s entering into civil twilight.
So on the ninth, Venus will just be three degrees from the crescent moon.
That’s about three fingerwidths and it’ll be a very fine binocular sight, you might even be able to get it into the field of view of wide angle telescopic eyesight.
Venus currently looks like the gibbous moon and heading towards full moon and shape and shrinking as it’s getting ready to disappear into conjunction with the Sun.
Brendan: Yep …
Ian: Now Venus and Mars you may remember had a spectacular conjunction last month. They’re still close together. So at the beginning of March, Venus and Mars are around five degrees apart. That’s about four finger widths to five finger widths apart in the morning twilight. And then they sort of pull further apart as Venus sinks and Mars arises into the morning sky.
Venus has also has a very close encounter with with Saturn this month. So Saturn, which has been lurking close to the Sun, enters into the morning twilight. But it’s very dim in the twilight.
From the 19th to 25th, Venus and Saturn are quite close. And on the 22nd, they’re closest at 0.6 of a degree. That’s just a little bit under a finger width wide.
However, because they’re relatively deep in the twilight, you’re going to need binoculars to see Saturn. So Venus will still be very easy to see, but Saturn is going to be a little bit tragic to get a hold of.
Brendan: Oh …
Ian: Mars, as I’d said, is climbing higher in the twilight. And on the eighth, the crescent moon at Mars and Venus form a line that will look very nice in the early morning sky. and that’s about it for the morning sky.
Brendan: Very good Ian and we’ve got that equinox to look forward to as well. Now last month Ian, you gave us an astrophotography challenge and I got a camera ready …it was all primed, batteries charged, SD card already, I’ve got the correct lens … and then I was clouded out !!
So could you do two things for us Ian? I was going to have another shot in the March full moon but you’ve recommended that I wait until June … could you tell us two things … firstly why should I wait for June to have another go at your first astrophotography challenge?
And secondly … how did you go taking your photographs of the moon?
Ian: I’m going to answer your second question first. I went reasonably well, although I was somewhat tree challenged. And to answer why I was somewhat tree challenged, I need to go back to your first question. The problem with the moon in summer is that the ecliptic at night is very low to the horizon.
So in summer, the path of the sun is high in the sky here in Australia.
And at nighttime, the path of the ecliptic is very low at nighttime.
In winter, it’s reversed … the path of the sun, and the ecliptic is very low, whereas the path of the ecliptic at nighttime is very high, which is why it’s better for planetary oppositions to be observed in winter because the planets will be much higher in the sky … they’ll be in clearer air so you don’t get as much distortion of the planetary surfaces by the atmosphere leaping about like a crazy thing.
This has been a quite a challenge which my attempts to photograph Jupiter recently because even though I’ve got a nice clear view of Jupiter it’s relatively close to the horizon and it’s quite hot here in Adelaide so the atmosphere dances around like a crazy thing.
Brendan: Oh …
Ian: So in June and July the ecliptic will be at almost at their highest so if you wait until June or July we’ll see the moon come more or less straight up.
This gives us two advantages. And that’s because it’s higher in the sky, you get a better chance of seeing the reduction in the moon’s diameter as it goes up.
And there’s less likelyhood for things to get in the way. So for example, although I got lots of photographs of the moon … I was able to photograph the moon at 15 minute intervals from bracketing the time when the moon was highest in the sky.
But I was very tree challenged and a moon was hanging out behind a tree for a substantial amount of time. So for the best resolution, you want to get the moon not too far away from when it rises to when it’s highest in the sky.
If you’re too close to moonrise then the distortion of the moon through the atmospheric shenanigans means your measurement of the diameter is going to be a bit off.
So it’s nice to get the moon a little bit higher above the ground but it’s good to have a nice big travel between when it’s a decent height above the horizon to avoid atmospheric distortion to the zenith where it’s at furthest from the earth and also has less atmospheric distortion
Brendan: Yep
Ian: So I haven’t analyzed my data yet … we’ve got all the photos … I just have to run them through Python … but lots of other things have been happening since Saturday night … so i will get around to it
Brendan: So watch this space …
Ian: Watch this space indeed …
Brendan: What else have you got for us for the month of March Ian?
Ian: Well first … before I go on to my tangent, I’d like to draw attention to a unregarded open cluster … now every year around about this time I wax lyrical about the Southern Pleiades which is a nice little cluster of stars centred around Eta Carina and … Well, they are very nice … there’s an overlooked cluster with the unprepossessing name of NGC 2516. Southern Pleiades sounds a lot cooler, but NGC 2516. If you remember from the last talk, I guided you to the Southern Pleiades with reference to it being almost directly between the Southern Cross and the False Cross.
But … if you go up to False Cross itself, just a little bit below a bottom star of the False Cross is NGC 2516.
If you look with the unaided eye, if you see the kite shape of the False Cross and the bottom star of the long axis has a fuzzy little nebulosity just at the end of it. And if you look at that in binoculars, you’ll see this wonderful little cluster of bright and shiny stars.
And if you look at it in a telescope, it’ll look really quite nice. So again, if you’re out from now till past the new moon and you’ve got your binoculars on you, … Look up at the false cross and we tend to ignore the false cross because it just confuses us about the southern cross. But have a look at the end star of the stem of the false cross and you’ll see a lovely little cluster of stars well worth gazing at.
I was also going to talk about the penumbral lunar eclipse … except for the vast majority of us. We’re not going to see it. It starts during the afternoon, the maximum eclipse is when the moon is still below the horizon, and so it’s not really worth our time. I do like penumbral eclipses because you can see the subtle shading of the outer earth shadow on the moon, but this year it’s not really worth it.
Brendan: Yep.
Ian: And with that, let’s move on to this month’s tangent. So, I’ve been talking a lot about the moon … about how we can measure the moon’s size, the disappointing penumbral eclipse … But did you know Venus has a moon?
Brendan: No.
Ian: That’s called the ‘Zoozve’ … I don’t really know how to pronounce that. So … Z double O, Z V, E. Well… it’s sort of a moon.
It’s a ‘quasi’ moon. Now, the saga of Zoozve started when Lattif Nassar noticed that the wallposter of the solar system in his son’s bedroom showed Venus for the moon, labelled Zoozve.
Now, Lattif was sure Venus had no moon and started asking around. He asked both NASA and the illustrator who made the poster, and he found that Zoozve was actually the asteroid 2002 VE. So the illustrator had made a typographic error in making the poster. But 2002 VE was a quite interesting object.
It’s a quasi -moon of Venus. Now, I’m not going to recount Latif’s journey because he does much better himself in his Radio Lab podcast. If you look up Radio Lab in your favourite web searching device, from 26th January 2024, he’ll tell you all about his journey to find Zoozve.
So …but a lot of you are asking, “What’s a quasi moon?” Now, you’re familiar with standard moons, and many like Earth’s Luna, the Galileo moons of Jupiter, Titan, Miranda, and Charon … they could be planets in their own right. And … that’s a discussion for another day.
Brendan: Yep …
Ian: And there’s Phobos, Deimos, Pan, and the like, which are basically grappled with attitude. But all of these are united by the fact that they orbit their parent body.
And the parent body is orbiting the Sun, but all of these are orbiting their parent body.
Quasi moons don’t orbit their planet, but they orbit the Sun. But because they’re orbiting period matches the planet very closely … they’re called quasi moons.
Brendan: Cool.
Ian: They’re generally in phase and follow the path of the planet quite closely, … but they’re not gravitationally linked to the planet, they’re gravitationally linked to the sun.
Now Zoozve was actually the first quasi -moon found but they didn’t know it was a quasi -moon at the time it was found, it was only after it was discovered …. two years later … that is was a quasi -moon.
And it closely matches Venus’ orbit. Sometimes it leads it, sometimes it falls behind.
Now, while it’s closely matched to Venus’ orbit, it’s a bit eccentric and sometimes its orbit comes out as far as Earth’s orbit.
Now, as we’ve seen, it’s about 236 meters in diameter and it might be a contact binary. Now, there’s a lot of these asteroids in the solar system which we think are just interesting elongated objects but actually turn out to be contact binaries.
If you remember the first target of the Lucy mission turned out to be a contact binary.
Many of these quasi moons are quite stable … for example Zoozve is in its quasi orbit for at least the last 7 ,000 years.
Okay so that’s astronomical terms, that’s not very long at all. And it’s probably destined to be ejected from this orbit in about 500 years or so from now. Now Earth has six known quasi satellites.
Although the most famous secondary moon of Earth, which that goes by the undistinguished name of 3753 Cruithne is actually a co -orbiting object.
I’m not going to go into the distinction between a co -orbiting object and a quasi -moon.
The other true quasi -moons, interestingly, are named 469219 Kamo’oalewa which was discovered by a Hawaiian observatory, is the most stable of our quasi satellites and around for many hundreds of years.
And it’s about 40 to 100 meters in diameter. So not as flashy as Trinity or as Zoozve, but still quite interesting in its own right.
And there’s also the Trojan satellites, the Trojan asteroids, a bunch of asteroids that are in gravity, spatially stable orbits ahead or behind the planet. Earth has a couple of Trojan asteroids. Jupiter has a whole bunch of Trojan asteroids and leading and trailing Trojans. But again, this is a story for another time. Let’s go back to Zoozve.
So Seppo Mikkola, who was the discoverer of Zoozve, had a story so charming that he proposed the name Zoozve on NASA’s behalf to the International Astronomical Union, specifically to their committee. And they were also charmed by it. And it’s come to pass that 2022, the ’68 is now officially 524522Zoozve. Hereafter, we will just call it Zoozve. And so a charming topographical error on a child’s poster is now enshrined in a nice name in the heavens. Nice. Very nice indeed.
Brendan: And Ian, do you want to do a challenge for us for this month? I know I failed on the first one and I’m going to try again in June.
Yeah, well all of our quasi -moons are too small for people with ordinary gear to catch. But one thing you can do is photograph another iconic asteroid and that is Vesta.
Now for Vesta is fading but it’s still within the binocular view and it’s also within the bounds of most modest cameras.
So Vesta is currently between the horns of Taurus the Bull, between the bright Elnath and Zeta Tauri which mark the tips of the horns of the Bull so it’s easily relatively easy to find but for this you’re going to need a piece of software.
I use DeepSkyStacker and what DeepSkyStacker does is it takes a bunch of photographs you’ve taken and stacks of all one on top of the other and so you can bring out very deep objects so if you just stuck your camera pointed it between the Horns of the Bull and took a photograph, you’re not likely to pick up Vesta just with a ordinary everyday camera.
But if you take your ordinary everyday camera and say take 10 images in a row and stack them in DeepSkyStacker, you’ll be able to boost the brightness of all the faint stars and if you play around with controls of it … reduce the darkness of the night sky and you ll be able to bring Vesta out … you may need to do this over a couple of nights so you can see Vesta moving … from the time this podcast comes out till we see the first quarter moon the skies will be pretty dark and even up even under most suburban skies, with the help of DeepSkyStacker, should it be, in principle, able to pull out, Vesta, and see it move against the background stars. So this is a little bit more technical than the previous challenge where you just had to take lots of photographs of the moon.
You’ve got to take lots of photographs again, but you’ve got to take lots of photographs of the sky between Elnath and Zeta Tauri. It’s still quite high at Astronomical Twilight but the sky is very dark as Taurus and the horns of the bull are quite easy to find and you don’t really need to actually locate the best of with your eye or binoculars in order to do this you just need to be able to. take … do a little bit of zoom to get the space between the horns of the Bull and take a number of images in a row … you may want to do 20 and then import them into DeepSkyStacker.
DeepskyStacker can be found by entering the name ‘DeepSkyStacker’ into your favorite internet searching engine. engine and it’s free to download It doesn’t take up much space It’s very computer friendly.
I’ve used in the variety of sad old computers as well as my new flashy computer and by judicious tweaking of the Conditions you can get it to stack tens of images instead of taking 48 hours to do so.
You may also find it worthwhile taking a dark image where you leave the cap on your camera, take a image with the same exposure conditions as you would for your sky imaging and this will take, the background current from your images and this also helps bring the stars out. So that’s my challenge for this month is to image Vesta between the horns of the bull and it will also give you access to a neat little piece of image processing software.
I use DeepSkyStacker quite a bit to stack images of the International Space Station going over so that I can get some nice nice trails of the International Space Station going over and I’m sure you’ll find that you’ll have lots of interesting …. that you play around with that you’ll find that you’ve got lots of interesting uses for DeepSkyStacker.
I also use the GIMP for astrophotography as well and so what I often do is output a DeepSkyStacker fully into GIMP, play around with the levels a bit too change brightness and contrast.
So you know, even though it looks quite nice when you pull it out from DeepSkyStacker in the first place, you may find that if you want to post dream images on the internet, you have to overexpose them a bit because the algorithms for posting on Twitter or Facebook mess up the background for a bit so that it becomes harder to see things that you can see quite nicely … become harder to see when you post it on social media.
So that’s my Astrophotgraphy Challenge, which will expose you to a new piece of software, which will expand your Astrophotgraphy horizons. Again, this is all with very modest equipment. You don’t need fancy, fancy cameras. You don’t need fancy, fancy telescopes. So it’ll be all quite easy to do with very modest equipment and you don’t have to pay huge amounts to get interesting results.
Brendan : Excellent. Well, I’m certainly up for the Vesta Challenge Ian and I’m looking forward to it. I’ll see what I can capture and I’ll send it to you. You’ll find it in your favorite email inbox.
Well, thank you very much. Ian ‘AstroBlog’ Musgrave. There’s lots for us to see in the sky and lots for us to do in our backyards.
Ian: Good night Brendan, we’ll catch you later. I’ll also post some spotter charts for Vesta later on in the week after this comes out okay?
Brendan: Oh yes we always send people to go and check out Ian’s AstroBlogger website.
Ian: Indeed indeed. indeed. Welcome everybody.
Brendan: See ya, Ian.
Ian: See ya, Brendan.
Brendan: And remember, Astrophiz is free and unsponsored. But we always recommend that you check out Dr Ian Musgrave’s AstroBlogger website to find out what’s up in the night sky.
And in two weeks. weeks, we’re bringing you a wonderful interview from the recent Transients Down Under conference in Melbourne, Australia, where we spoke with Professor Orsola De Marco from the Astrophysics and Space Technology’s Research Centre at Macquarie University.
You’ll love her stories. Keep looking up. [MUSIC]
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