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Blog : Posts tagged with ‘astronomy’

Life on Mars

Well, maybe

Astronomy fans probably already all know about the Nasa rover Perseverance, which landed successfully on Mars yesterday evening. The Child Who Likes Animals Space was greatly disappointed that the landing wasn’t going to happen until well past bedtime. “You wouldn’t find it very interesting anyway,” I told him. “All you’ll see is a bunch of people in a control room cheering. You won’t get the good pictures until later.” Indeed, although there was one slightly low-contrast black and white photo through within a few minutes to prove the lander had touched down the right way up, at the time of writing the good exciting stuff is due to be revealed shortly.

As the sun went down, though, the sky outside was crystal-clear and Mars was clearly visible a few degrees above the Moon. “Shall we get the telescope out and look at Mars ourselves instead?” I suggested, and of course The Children jumped at the idea.

I’m getting a bit bored of starting posts on here with “Since we moved house…”, but this is the natural point where I have to say “Since we moved house…”. Specifically, since we moved house, The Child Who Likes Space’s telescope has sat in its box in a cupboard; after all, it is February in Wales and we have hardly had a clear night since we moved in. So last night was the first time in this house that I took the telescope out of its box, set it up in the garden on the camping table, and looked to see what we could see.

To be honest, I wasn’t very hopeful. The new garden has a bright-white LED streetlamp shining straight into it. Moreover, as soon as I went outside, on came an automatic outside light. Could I find an off-switch for it anywhere? No, I could not. I was rather d, given these problems, to see that the sky was a wonderful bright blanket of visible stars, much clearer than anything we could ever see in Bristol.

Mars was easy to find, but still is barely more than a dot with the magnification we have available. After looking at Mars, we saw Orion was bright to the south, so zoomed in on Betelgeuse and then the Orion Nebula, or Messier 42 to its friends. In Bristol, the Orion Nebula only ever appeared in the eyepiece as a pale fuzziness which barely stood out from the background sky. Here, it was startlingly clear by comparison, a cold blue cloud against the background sky. Compared to our previous attempts to observe it, it was an entirely different experience.

By now clouds were starting to roll in from the north, so we packed everything up and went inside. As one last thing to try, I pointed the telescope at the moon and tried holding my phone to the eyepiece. Previously when trying this, I produced possibly the worst astrophotography ever. Last night’s attempt, therefore, can take the second-worst spot.

The moon

Maybe at some point I’ll actually get a proper adapter to strap my phone into and produce something slightly better.

At some point, when we can travel more widely, we’ll have to try putting the telescope in the car and heading up to one of the dark sky sites in the Brecon Beacons, to see just what we can see when we are out of town altogether with no streetlamps and no lights in neighbouring windows. For now, we’ll just have to wait for the next clear night, and see exactly how dark it is when we’re just in our own garden. Fingers crossed.

New star in the sky

Or, some astronomy news

When you’re learning about astronomy, you quickly get used to the idea that on a human timescale everything is static and nothing really changes. The Earth is going to be swallowed up by the sun,* but it won’t be for a few billion years yet. When you look up at the sky the light you see from other stars has been travelling for hundreds, thousands or millions of years. In general this is all part of the Copernican principle: on a universal scale there’s nothing special about where we are or when we are, other than that we could only be living at a time and place where planets are commonplace. Therefore, there’s not a very high chance of anything special happening whilst we’re looking.

However, that doesn’t mean that interesting things can’t happen. Before the end of the century, there will briefly be a new brightest star in the sky.

The star in question is V Sagittae (or V Sge to its friends). Sagitta—not to be confused with Sagittarius— is a small constellation adjoining Cygnus. Unless you’re an astronomy fan it’s the sort of constellation you might not even have noticed, as it’s small and it doesn’t have any very bright stars in it. Living where we do, I’d struggle most nights to see even its brightest star with the naked eye. V Sge is in theory just about visible in The Child Who Likes Animals’ telescope; it’s around magnitude 10, although it varies quite a bit and over quite short timescales.

Since it was first discovered it’s been realised that it was a bit unusual. It’s a binary system, with an “ordinary” sun-like star orbiting around a smaller white dwarf. More recently, astronomers realised that the pair of stars were getting noticeably brighter over time as their orbit shrinks and they get closer to each other. Last week, it was announced that at some time in the last three decades of the current century, they will finally spiral into each other and temporarily become the brightest star in the sky. If you want to know full details, this is the press release of the announcement from Louisiana State University, and here are links to the full data.

At present the time range is a bit on the vague side, but it will almost certainly happen in a 32-year span centred on 2083. No doubt, now that more astronomers know about this, we’ll get more data over the next few years to narrow down the time range. And even before then, V Sge will probably get a bit brighter over time, as it’s doubled in brightness in the past 90 years. I might even see if we can see it ourselves now if we get good conditions: its part of the sky is well-positioned for early evening viewing from here at this time of year. I’m not likely to see it go nova myself, but The Children might do.

* Assuming nothing else catastrophic happens to it first, such as being kicked out of the Solar System completely. It’s unlikely but it’s not impossible.

Under clear skies

Or, some unexpected astronomy

“Is it cloudy or clear?” said The Child Who Likes Animals yesterday evening after finishing his tea.

“I don’t know,” I said, knowing the weather forecast was showing a solid grey sky for the whole of the evening. “Let’s have a look,” knowing there was little risk of us being able to look at the stars.

I opened the back door, and was rather surprised to see clear skies and good visibility. “LET’S GET THE TELESCOPE OUT!” screamed The Child Who Likes Animals Space. I had been planning to head straight to the sofa and the book I’m in the middle of reading,* but agreed that, if we could come up with a sensible plan for what we were actually going to look at, I would set it all up for him.

We fired up Stellarium and I tried to find things that would be interesting to see and straightforward to find. Outside, I had already seen the cross of Cygnus was fairly high in the sky, with Cassiopeia above it, so I make a risky suggestion. “Why don’t we try to see the Elephant’s Trunk Nebula?” I said, knowing that with our inner-city skies nebulas and other deep-sky objects do not put on a very good show. It does, though, have a very child-friendly name.

I set the telescope up on the table outside, and tried to get my eye in. It was immediately obvious that viewing conditions were on average far, far better than they had been on New Years Eve. The Elephant’s Trunk Nebula has the benefit that it’s close to an easy-to-find star, Alderamin (α Cephei). I quickly navigated ten degrees south to the location of the nebula, was confident I was there from the pattern of the stars. And was there anything? Well … maybe. Charitably, I could convince myself that the sky did indeed look slightly brighter than elsewhere in the sky; that I could see hints of structure that were not just inside my own eyeballs and brain. The Children, though, would have none of it.

Luckily, I’d noticed there was something interesting just by the nebula, and confirmed with the computer that I was looking at Herschel’s Garnet (μ Cephei). It’s a red supergiant star, a thousand times broader than our sun, and a distinctive pale peach colour to the eye—the astronomer William Herschel described it as “deep garnet”, hence the name. As its colour is so clear to see, The Children were reasonably impressed.

As it was so clear, we also pointed the telescope at the Pleiades, the view of which wowed The Child Who Likes Fairies (“There’s literally trillions of stars!”) then, the cluster NGC 7686 and the Andromeda Galaxy. The latter was, to my eyes, a slightly clearer fuzzy blob than it has been in the past, but still just a fuzzy blob. The Child Who Likes Animals said he could see it clearly; The Child Who Likes Fairies could not.

Thinking about what we should be able to see in the sky, I did a bit of maths. Say the pupil of one eye when it’s dilated is about 8mm wide—I’m just guessing this part really. We’re using a 150mm telescope: that’s 350 times as large as a pupil, so it gathers 350 times as much light. That’s a difference in astronomical magnitude of just under 6.4. Now, when I was aiming the telescope last night, once my eyes were adapted I could just about make out stars of magnitude 3.8 to 4.2; such as the stars λ Andromedae, κ Andromedae and ι Andromedae, which I used to find NGC 7686 and which I’ll have to write about again some other time.** I suspect that that’s as good as things are ever going to get in our hazy and light-polluted urban sky. But taking the telescope’s light-gathering power into account, if I’ve got the theory correct, I should be able to see things of magnitude 10 to 10.5 or so through it. Next time we have good seeing, I should test this out: look up at a few things and find out what the official magnitude of the stars I can just barely see is.

When I’ve done that, of course, I should probably think about getting some way to record what I can see, rather than just trying to describe it to you. The Child Who Likes Animals’s telescope is a Dobsonian with an altitude-azimuth mount, which means long-exposure photos are probably out, but I’d like to look at our options and see exactly what we could try to do instead.

* The Northmen’s Fury: A History of the Viking World by Philip Parker.

** Because in looking up their names for this post, I’ve discovered they form part of the former constellation named after Friedrich the Great of Prussia, Honores Friderici.

More meteors

You wait for months, and then...

Another small astronomy note: the first of the year’s big meteor showers occurs over the next couple of days. I know it’s less than a month since the last big meteor shower of 2020, the Geminids, but tomorrow we have the peak of the Quadrantid shower. They’re a bit harder to see than the Geminids, partly because they’re usually fainter and partly because they’re concentrated into a narrower stream, so they’re seen over a much shorter time-range. Moreover, looking at the weather forecast, I doubt we’re going to have clear enough skies to have any chance of seeing them.

Interestingly, the Quadrantids are named after a constellation that doesn’t officially exist any more. Their name comes from Quadrans Muralis, “the wall-mounted quadrant”, a constellation named in the late 18th century by Jerome Lalande—he named it after an astronomical instrument he’d used to help him map the sky. Naming constellations after scientific machinery was quite fashionable in the 18th century; we still have Antlia, Horologium, Microscopium, Octans and Reticulum in the sky, to name just a few. Nevertheless, when the boundaries of the constellations were officially defined by the IAU back in the 1920s, Quadrans Muralis was left out of the list. Its part of the sky is now mostly split between Draco and Boötes, with a small piece in Hercules. You could argue the Quadrantids should really have been renamed the Boötids, but the old name has stuck.

End things as you mean to go on

Looking up at the sky again

Happy New Year!

Last night was the first clear night for a few weeks; and the only clear night at any point in the forthcoming weather forecast. Naturally, as soon as I mentioned the clear skies to The Children, they immediately jumped up and down and shouted “LET’S GET THE TELESCOPE OUT!”

The decking was already slippery with frost, and there was a lot of light and noise from the surrounding houses, but we started out by pointing the telescope to Enif (ε Pegasi), a red supergiant with a very distinctive orange colour. From there we navigated to the nearby globular cluster Messier 15, which I could see in the telescope as a somewhat hazy blob, but which The Children weren’t sure they could actually see.

After they were in bed, I went outside again and looked up at the sky, but it was already filling up with haze and smoke from the fireworks sporadically going off all around the neighbourhood. I tried to find Messier 36, an open cluster in Auriga apparently also called the Pinwheel Cluster, but could not actually make out any of the stars in it. I looked at the Pleiades to calibrate myself, and realised there seemed to be far fewer of its stars visible than normal. As Orion was rising higher in the sky I pointed the telescope at the Orion Nebula, just about visible as a couple of fuzzy points; and the nearby Coal Car Cluster (NGC 1981). The latter’s stars are around magnitude 6.4 to 7.4, which normally would be clearly visible in the telescope even in our inner-city skies, but with last night’s firework haze I could just about make them out.

Ah well, there will be clear nights later in the winter I’m sure. I got up again about 3am to get myself a drink, and the garden was covered in a thick fog of smoke still from all the fireworks of midnight. Fireworks and astronomy do not mix. Hopefully later in the year, too, we’ll be able to take the telescope to somewhere with properly dark skies one night.

Cloudy skies

And not much we can do about it

Sadly, I didn’t get to see the Great Conjunction of Jupiter and Saturn, at least not at the closest approach that would have been visible. We had heavy rain here this afternoon; and after sunset the sky was a uniform, undifferentiated cloudy mass with not even the moon visible.

Oh well: we had clear skies last night, at least, and I did see them both, maybe only about 10 minutes or so apart in the sky, just over the horizon after sunset. I tried to take a photo on my phone, but although Jupiter was clearly visible on it, Saturn was only really spottable if you already knew it was there. Maybe it’ll be clear skies tomorrow, when they are parting again.

The solstice has passed too, of course. Politically this country might seem be descending into some sort of nightmarish fimbulvetr right now, but at least the heavens don’t know that.

The shape of the sky

Or, confusing perceptions

This is an astronomy post, but it’s also not really an astronomy post; it’s more a post about me and the way I think.

When I was small, I was terrified by the size of the universe. I can remember, about seven or eight or so, really struggling with the concept that the universe might be infinite and might not be, and I can still remember the mental picture I tried to come up with of a universe where the stars just, at some point, stopped; and beyond there was just blackness.

It probably doesn’t work like that, but still in my head somewhere is the concept that it might do. Moreover, I have trouble with another, broader concept, which is that—assuming you can travel between both hemispheres—we can “see” all of the observable universe.

“See” is in quotes there because, well, you can’t see everything for practical reasons. Most things are too faint, firstly. At any given time half the sky is too close to the Sun, too: you can’t see Mercury right now for example. But in theory, barring things being too faint, barring you having to wait for the Earth to move a bit or having to travel from one side of the Equator to the other, the whole universe is up above some point on the planet’s surface at any given time.

This probably seems tediously self-evident if you think of the planet as a ball spinning through space. For some reason, though, the whole concept still catches me by surprise occasionally. I still think that things must be able to, I don’t know, hide around a corner or something like that. I think I must have picked up the idea from a book I had as a child about Halley’s Comet, which included diagrams of where you would be able to see the comet in the sky in 1986, and talked about how comets appeared and disappeared in the sky. That’s the general tone when talking about comets and asteroids and so on: they appear in the sky and they disappear again. So it took me a long time to realise that all of the comets and all of the asteroids are up there, in front of us, all along; we just can’t see them right now. Halley’s comet doesn’t just pop out from behind a tree every seventy-five years: it’s up there in the sky the whole time, just not visible.

Halley’s comet is maybe a bad example for this. Because it’s so famous, and because of the light-gathering power of modern telescopes, we can now track it through its entire orbit. According to Stellarium it’s currently at coordinates 8h26m/+1°46’, but as it’s only a few years from perigee it’s an incredibly-faint magnitude 25.5 so will appear as a just a fuzzy handful of pixels on any photo. Nevertheless, if you go outside tonight and look up at the constellation Hydra close to its tripoint with Monoceros and Canis Minor, up there it is. As are all the others. Everything in the sky that you’re likely to see in your lifetime is already up there in the sky, just invisible and unrecognised. And despite the fact that I know this, that I know on a rough, superficial level how the mechanics of cosmology work, it still feels a little strange to me. It still feels in my mind as if there should be some patch of the sky that we can’t see, that is hiding around some sort of galactic corner.

Whenever I see diagrams of the whole sky that say “this is the whole universe”—cosmic background radiation maps, for example—I’m slightly disturbed that in some sense the whole universe fits into one small image. “Surely it must be bigger?” my mind ends up thinking. The edges trick me: that’s not the edge of the universe, it’s just an artifact of plotting a spherical sky onto a flat piece of paper, just like any sort of atlas. The mental disconnect, though, leaves me feeling deeply uncomfortable.

Really, what I feel I should inspire me here is to take away that the night sky is far more mysterious and secretive than we know. It’s not just laid out flat in front of us as it appears to be: it’s full of unknown things and unanswered questions, even though all of them are genuinely sitting right there up above us somewhere. I don’t know if I’ll ever manage to change the way my head thinks about the night sky, but if I can, there is a whole universe of wonder concealed but fully within sight.

The stag cry and the slaughter

Or, the turning of the year

A few weeks ago, I read on Twitter—sadly I seem to have lost the reference—that the Welsh Hydref, used for either the month of October or autumn as a whole, originally had the literal meaning of “stag-cry”. From that, it turned into “stag-rutting season” and hence autumn. Geiriadur Prifysgol Cymru lists “stag-rutting”, but not “stag-cry”.

Moreover, November, mis Tachwedd, literally means “the month of slaughter”. Together, I think they make a beautifully evocative phrase. The stag-cry and the slaughter. Winter is setting in.

I spent a while sitting outside on clear nights over the past week, hoping to see the Geminid meteor shower. Nothing much, sadly, came of it. On Saturday, though, I did see a handful of meteors in the night sky. I’ve always looked for summer meteors before, flashing across the sky in a razor-thin line; but these were relatively slow-moving, fat things. I say “slow-moving”: they still crossed my field of view in little more than an instant. Their light was a much broader line, though, tapering at start and finish. If nothing else, it gave me good inspiration for the story I posted yesterday. Hopefully I’ll have better luck when the Geminids come around again next year. This year, though, is now nearly at an end. The stag-cry and the slaughter, and winter is upon us again.

Astronomy news of the week

Or, how to spot a shooting star or two

This is not going to turn into an astronomy blog, I promise, and I know I already mentioned some exciting upcoming astronomy news just over a week ago. There is something else interesting and astronomical happening in December, though.

In the meantime, the clouds did briefly break on Saturday evening to give us our first chance of using The Child Who Likes Space’s telescope without the moon shining bright in the south. We had a look at Mars, and then I successfully found Uranus, navigating downwards from Sheratan, the nearest naked-eye star I could easily pick out; it’s currently near to the boundary between Aries and Cetus. Looking just like another blue star, I would have had no idea, without guiding myself with a map on the computer, that we were looking at a planet instead.

And then, naturally, I started sending messages to people saying “Guess what? I’ve been spying on Uranus”, because I still have the sophisticated sense of humour of a ten-year-old.

The exciting event that’s coming up in a week or so’s time is: the Geminid meteor shower. I say “coming up”: it’s expected to be at its strongest at around 2 in the morning next Monday (the 14th), but if it is a strong shower this year, there should be activity visible for a few hours either side of that time, and even for a few days. Incidentally, because of the geometry of how meteor showers work—they happen when the Earth passes through the trail of dust left behind a comet or asteroid—the peak time is the same wherever you are, with the location of the peak moving around the planet as it spins. The Geminids were first noticed in the 1860s, but their “parent”, the asteroid 3200 Phaethon, was not discovered until 120 years or so later.

I’m not sure I’m going to risk keeping The Child Who Likes Space up until midnight to watch for meteors, much as I’m sure he would like to. If the skies are clear late one night this week, though, I might try wrapping up warmly and setting up my deckchair in the garden. There’s no point trying to use a telescope or binoculars to spot meteors; all you need is a comfy chair you can lie back in and look up at the sky. Give your eyes half an hour to adapt to the dark, then look up, look around, and wait for them to streak across the sky.

More astronomy news

A significant event is coming up

One last astronomy post for a while, and then I’ll talk about something different, I promise: in a few weeks time, on December 21st Saturn and Jupiter will be at their closest conjunction for several hundred years.

The Plain People Of The Internet: Conwhatnow?

They’ll come close together in the sky. The closest they’ll be for a few hundred years, in fact. They’re already fairly close in the sky right now, but on December 21st they’ll be so close that to some people they’ll look like a single spot of light, although people with 20/20 vision should still be able to see they are two separate dots.

Unfortunately … I’m not sure I’ll be able to see it. They’re both on the far side of the sun from us right now, and we’re basically watching Jupiter passing in front of Saturn from our perspective on the other side of the solar system. Because of this, they’re also fairly close to the sun in the sky, which means you don’t get a very long window of opportunity to see them. They will set together in the south-west sky only about 90 minutes after the sun does, so you have a brief window of time to see them together at dusk. If you’re on a south coast then things are grand; if you’re in a town, they may well be already below your neighbour’s roofline before the sky gets dark enough to see them. Personally, our only chance will be from an upstairs window. Fingers crossed, though, the sky will be clear enough to see something of them both together.