Between The Wheels

Between The Wheels => Technology and Science => Topic started by: Slim on January 30, 2026, 03:50:35 PM

Title: A General Astronomy Thread
Post by: Slim on January 30, 2026, 03:50:35 PM
Went outside on a clear night during the week, and noticed Orion was very clear. It looked exactly the same as it did when I was 9, which was actually a bit of a melancholy thought. It made me think of my own impermanence.

So anyway I did a bit of googling and ChatGPT research and it turns out that all of the Orion stars are, in cosmic terms, very short lived.

Our own local star's total lifespan is roughly 10 billion years. The Sun is a bit less than half way through its expected life. By contrast the longest total lifespan from birth to death of the Orion stars is that of Bellatrix, which will have lived about 40 million years when it dies. Animals on Earth with the ability to see stars in the night sky existed before any of the Orion stars was born. Fingers crossed some will exist when it dies, as well.

(https://i.ibb.co/NM1Kcf3/orion.avif)

Rigel is the brightest Orion star. Its total birth-death lifespan is 8-10 million years and it's had most of them already. By contrast the Sun's lifespan is 1000 times longer. Rigel is about 420,000 times the size of the Sun by volume and it gives out approximately as much light energy in a second as the Sun does in a day and a half.

Of course over a few thousand years, because the stars are moving, Orion will look a bit different. But since I was 8 or 9, the difference in the shape is imperceptible.

Imagine that 56 years ago, I drew an exact, 5 metre drawing of Orion on a huge piece of paper. If I wanted to update it today, I'd need to move Betelgeuse (the most "mobile" star in the constellation in 2D terms) by about a tenth of a millimetre.
Title: Re: A General Astronomy Thread
Post by: Fishy on January 30, 2026, 05:25:12 PM
Can anyone recommend a decent telescope  for home use ? I was at a dark skies place near Hexham a couple of years ago and I asked the guy but I cannot remember the make he said...
Title: Re: A General Astronomy Thread
Post by: Thenop on January 30, 2026, 05:57:22 PM
We have a not so expensive table model Celestron. Hardly used, come to think of it I should really take it out more. Works fine for me and didn't break the bank.
Title: Re: A General Astronomy Thread
Post by: Nickslikk2112 on January 30, 2026, 06:52:45 PM
Quote from: Fishy on January 30, 2026, 05:25:12 PMCan anyone recommend a decent telescope  for home use ? I was at a dark skies place near Hexham a couple of years ago and I asked the guy but I cannot remember the make he said...
I've got a 4.5" Bresser Optic refractor.

Barely use it these days, in Summer it doesn't get dark until too late and it's not an exciting time astronomically.

We hardly ever seem to get clear skies in Winter these days and that's the most exciting time astronomically. Of course clear Winter skies mean cold and frosty.
Title: Re: A General Astronomy Thread
Post by: Nickslikk2112 on January 30, 2026, 06:57:19 PM
Quote from: Slim on January 30, 2026, 03:50:35 PMI'd need to move Betelgeuse (the most "mobile" star in the constellation in 2D terms) by about a tenth of a millimetre.
Betelgeuse is a likely candidate to go Supernova and hence disappear to the naked eye, although the recent discovery of a companion star - Siwarha - has pushed the date of explosion back.

https://starwalk.space/en/news/betelgeuse-star-will-be-supernova#siwarha-and-betelgeuse-why-the-supernova-will-have-to-wait
Title: Re: A General Astronomy Thread
Post by: Slim on January 30, 2026, 07:19:19 PM
I looked up possible Supernova candidates:

(https://i.ibb.co/5Wsff4xq/gptnovas.png)

So it's possible that Eta Carinae has already "gone off", but we won't know for a few thousand years. Or tomorrow! Either is unlikely, especially tomorrow.

Title: Re: A General Astronomy Thread
Post by: The Picnic Wasp on January 30, 2026, 07:44:17 PM
Quote from: Slim on January 30, 2026, 03:50:35 PMWent outside on a clear night during the week, and noticed Orion was very clear. It looked exactly the same as it did when I was 9, which was actually a bit of a melancholy thought. It made me think of my own impermanence.

So anyway I did a bit of googling and ChatGPT research and it turns out that all of the Orion stars are, in cosmic terms, very short lived.

Our own local star's total lifespan is roughly 10 billion years. The Sun is a bit less than half way through its expected life. By contrast the longest total lifespan from birth to death of the Orion stars is that of Bellatrix, which will have lived about 40 million years when it dies. Animals on Earth with the ability to see stars in the night sky existed before any of the Orion stars was born. Fingers crossed some will exist when it dies, as well.

(https://i.ibb.co/NM1Kcf3/orion.avif)

Rigel is the brightest Orion star. Its total birth-death lifespan is 8-10 million years and it's had most of them already. By contrast the Sun's lifespan is 1000 times longer. Rigel is about 420,000 times the size of the Sun by volume and it gives out approximately as much light energy in a second as the Sun does in a day and a half.

Of course over a few thousand years, because the stars are moving, Orion will look a bit different. But since I was 8 or 9, the difference in the shape is imperceptible.

Imagine that 56 years ago, I drew an exact, 5 metre drawing of Orion on a huge piece of paper. If I wanted to update it today, I'd need to move Betelgeuse (the most "mobile" star in the constellation in 2D terms) by about a tenth of a millimetre.

I love the name Betelgeuse. I'd never heard of the size of Rigel. The size of our Sun is unimaginable to me. 420,000 times larger is mind blowing. Strange the our star is only known as the Sun and doesn't have another astronomical title.
Title: Re: A General Astronomy Thread
Post by: Thenop on January 30, 2026, 08:28:04 PM
Quote from: The Picnic Wasp on January 30, 2026, 07:44:17 PMStrange the our star is only known as the Sun and doesn't have another astronomical title.

Then again we can pronounce it in about 7100 languages, so it has many names. Whereas Betelgeuse and Rigel are most likely designated as such because of their given name.
Title: Re: A General Astronomy Thread
Post by: Slim on January 30, 2026, 09:02:48 PM
Quote from: The Picnic Wasp on January 30, 2026, 07:44:17 PMI love the name Betelgeuse. I'd never heard of the size of Rigel. The size of our Sun is unimaginable to me. 420,000 times larger is mind blowing. Strange the our star is only known as the Sun and doesn't have another astronomical title.

Possibly a bit of a misleading figure that because (as any fule kno) a sphere's volume scales with the cube of the diameter. So it's only about 75x larger by diameter.

I love thinking about astronomical scales. So if the Sun were a football, Rigel would be a sphere the height of a 5-storey building. The Earth would be a tiny ball bearing, 2mm high and about 23.5 metres from the football Sun. The 5-storey Rigel wouldn't even be in the same country! 1300km away.
Title: Re: A General Astronomy Thread
Post by: The Picnic Wasp on January 30, 2026, 10:38:21 PM
Quote from: Slim on January 30, 2026, 09:02:48 PM
Quote from: The Picnic Wasp on January 30, 2026, 07:44:17 PMI love the name Betelgeuse. I'd never heard of the size of Rigel. The size of our Sun is unimaginable to me. 420,000 times larger is mind blowing. Strange the our star is only known as the Sun and doesn't have another astronomical title.

Possibly a bit of a misleading figure that because (as any fule kno) a sphere's volume scales with the cube of the diameter. So it's only about 75x larger by diameter.

I love thinking about astronomical scales. So if the Sun were a football, Rigel would be a sphere the height of a 5-storey building. The Earth would be a tiny ball bearing, 2mm high and about 23.5 metres from the football Sun. The 5-storey Rigel wouldn't even be in the same country! 1300km away.

So, if the Sun was the size of an average car petrol tank (remember those?) and it takes approximately two minutes to fill, then Rigel would take 583 days. I think. Wow!
Title: Re: A General Astronomy Thread
Post by: Matt2112 on January 31, 2026, 12:23:43 AM
"Space," it says, "is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space".
Title: Re: A General Astronomy Thread
Post by: Slim on February 15, 2026, 07:36:05 PM
Just been outside, surprisingly it's a very clear night in NW Leics at the moment. Just had the best view of Orion I think I've ever had! Belt and scabbard very visible.

Also - Jupiter is very bright tonight. As I was looking up I saw what I thought must be the ISS glide overhead - but it blinked out after a couple of seconds. Checked, wasn't the ISS. Must have been some other satellite.
Title: Re: A General Astronomy Thread
Post by: Fishy on February 15, 2026, 09:50:23 PM
ISS is due overhead tomorrow 5.25 in the morning..
Title: Re: A General Astronomy Thread
Post by: David L on February 15, 2026, 10:19:54 PM
Quote from: Fishy on February 15, 2026, 09:50:23 PMISS is due overhead tomorrow 5.25 in the morning..
I'll probably give that a miss  ;)
Title: Re: A General Astronomy Thread
Post by: Fishy on February 27, 2026, 10:18:02 AM
Six planets on show in celestial 'parade'  https://www.bbc.co.uk/news/articles/c4g3l0yzyxdo
Title: Re: A General Astronomy Thread
Post by: Fishy on March 01, 2026, 10:40:58 PM
Quote from: Fishy on February 27, 2026, 10:18:02 AMSix planets on show in celestial 'parade'  https://www.bbc.co.uk/news/articles/c4g3l0yzyxdo

Too cloudy here tonight...
Title: Re: A General Astronomy Thread
Post by: Slim on April 08, 2026, 08:23:24 PM
Didn't know this until just now but Halley's Comet is on its way back, already.

Persons of a certain age will remember its last visit in 1986. I can remember sitting in a coffee bar at Teesside Poly and watching a news item about it. A woman had bought a t-shirt for her kid with the text "I'll See It Again in 2061!"

That kid will be about 45 now. Anyway as of December 9th 2023, it's getting closer again.

https://www.livescience.com/space/comets/halleys-comet-begins-its-return-journey-to-earth-saturday
Title: Re: A General Astronomy Thread
Post by: Fishy on April 08, 2026, 08:44:48 PM
Venus has been really bright..late evening looking west.. lovely
Title: Re: A General Astronomy Thread
Post by: Fishy on April 12, 2026, 09:48:39 PM
Venus really bright again tonight..
Title: Re: A General Astronomy Thread
Post by: Fishy on April 15, 2026, 11:17:30 AM
Oldest known meteor shower to light up UK skies this week https://www.bbc.co.uk/weather/articles/c1d902y90g5o
Title: Re: A General Astronomy Thread
Post by: Fishy on April 19, 2026, 10:19:32 PM
Lovely crescent moon with Venus just below in a clear sky tonight
Title: Re: A General Astronomy Thread
Post by: Slim on April 22, 2026, 09:18:48 PM
Just had a look at Jupiter through binoculars - you can just about make it out as a disk. But I couldn't see the Galilean moons.
Title: Re: A General Astronomy Thread
Post by: Nickslikk2112 on April 22, 2026, 09:49:45 PM
Quote from: Slim on April 22, 2026, 09:18:48 PMJust had a look at Jupiter through binoculars - you can just about make it out as a disk. But I couldn't see the Galilean moons.
I can with my not especially good binoculars. Maybe not yet dark enough, or they're aligned in front of and/or behind Jupiter.
Title: Re: A General Astronomy Thread
Post by: Slim on April 22, 2026, 10:14:38 PM
Well - with the 500mm lens I did manage to get the moons. Top left: Ganymede. Just touching Jupiter at 4 o'clock - Europa. Then Io, and just faintly visible bottom-right, Callisto.

Notice the blur is oriented diagonally - that's the sky moving (so to speak), or more accurately, the Earth rotating. I used a 0.5 sec exposure at 400 ISO.

(https://i.ibb.co/Kxd3dkzr/galileanmoons.webp)


A few minutes later I confirmed what I'd seen on Stellarium:

(https://i.ibb.co/JRcDh0KB/stell-moons.png)
Title: Re: A General Astronomy Thread
Post by: Fishy on April 22, 2026, 10:26:18 PM
With lots of clear skies over the coming nights there is a good chance of seeing the Lyrid meteor shower.
While it has been ongoing since the 16 April, the peak is expected on Wednesday night.
Expect to see around 10 to 15 meteors an hour with surges of activity that could bring up to 100 an hour.
The Lyrid meteor shower is an annual event as a result of the Earth passing through dust left behind Comet Thatcher.
Title: Re: A General Astronomy Thread
Post by: Thenop on May 01, 2026, 03:17:07 PM
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Title: Re: A General Astronomy Thread
Post by: Thenop on May 06, 2026, 01:00:07 PM
While playing around with Google maps I zoomed out so far that I oened a menu on the left that let's you see all planets and moons in orbit of those planets, and you can zoom in as well. Never seen that feature, must've missed it before. This means I have more than one celestial body to marvel at up close and personal!

It let's you zoom in on the planets and moons, and even has the names of craters, just like a map of earth.
Screenshot to show you in over 20Mb, might just be best to check for yourself :-)

Edit: let's see if this works: direct link to Europa, the smallest moon of Jupiter:

Europa (moon of Jupiter) (https://www.google.com/maps/space/europa/@-1.5273677,174.500637,5665242m/data=!3m1!1e3?entry=ttu&g_ep=EgoyMDI2MDUwMi4wIKXMDSoASAFQAw%3D%3D)




Title: Re: A General Astronomy Thread
Post by: pxr5 on May 06, 2026, 02:40:12 PM
^ Just tried it, interesting. I had to turn on Globe View in maps to get it to work.