Astronomy and Space

Get your science fix here: research, quackery, activism and all the rest
Post Reply
User avatar
jaap
Snowbonk
Posts: 543
Joined: Mon Nov 11, 2019 2:05 pm
Location: Netherlands
Contact:

Re: Astronomy and Space

Post by jaap » Tue Jul 12, 2022 9:40 am

plodder wrote:
Tue Jul 12, 2022 8:53 am
The slidey thing here: https://www.theguardian.com/science/202 ... axy-images

It's not lined up right, right? These are two different bits of space?
The same bit of space but they are not lined up. The JW one is rotated about 1/6 of a turn anticlockwise and zoomed in a bit.

User avatar
Gfamily
Stummy Beige
Posts: 4112
Joined: Mon Nov 11, 2019 1:00 pm
Location: NW England

Re: Astronomy and Space

Post by Gfamily » Tue Jul 12, 2022 9:59 am

jaap wrote:
Tue Jul 12, 2022 9:40 am
plodder wrote:
Tue Jul 12, 2022 8:53 am
The slidey thing here: https://www.theguardian.com/science/202 ... axy-images

It's not lined up right, right? These are two different bits of space?
The same bit of space but they are not lined up. The JW one is rotated about 1/6 of a turn anticlockwise and zoomed in a bit.
The HST image itself is a composite from at least two imaging sessions as well - you can tell because there are 8 spikes on the brightest star's image - 4 very clear, and 4 offset by about 20 degrees.
HST offset.png
HST offset.png (87.92 KiB) Viewed 463 times
I suggest that one of the sessions was in optical range, and one in the near IR where Hubble has some capability.
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
ETA 5/8/20: I've been advised that the result was correct, it was the initial interpretation that needed to be withdrawn
Meta? I'd say so!

User avatar
dyqik
Light of Blast
Posts: 5557
Joined: Wed Sep 25, 2019 4:19 pm
Location: Masshole
Contact:

Re: Astronomy and Space

Post by dyqik » Tue Jul 12, 2022 11:09 am

Gfamily wrote:
Tue Jul 12, 2022 9:06 am
For an idea of the scale, imagine the photo on your phone's screen.
Now imagine you're a goalkeeper and the other goalkeeper is showing you this image from their goalline (I don't know why they have your phone, but bear with me). That's the area of the image* on the sky.


*Appx 7cm at 100 metres.
Or the goalie holding a tennis ball, if you want a purely sports* analogy.

Which is really big compared to one bit of what I do, which is more like a tennis ball on the moon. Or 7cm at 380,000,000 meters. This is the size of the ring in the EHT images.

And really small compared to the other bit if what I do, which is like 7cm at 10cm for the field of view (45° on the sky, sine rather than tangent because we're working on a sphere). This is roughly the size of the full map that makes up Gfamily's avatar.

Although the main thing I do has about the same image sizes as JWST.

*A sport with goals 100m apart that uses tennis balls. Or we could go to cricket, I guess.

User avatar
Stranger Mouse
After Pie
Posts: 1727
Joined: Sat Dec 21, 2019 1:23 pm

Re: Astronomy and Space

Post by Stranger Mouse » Tue Jul 12, 2022 3:48 pm

Someone here has done a nice Webb / Hubble overlay https://twitter.com/luckytran/status/15 ... e2L1NRD_bQ
I’ve decided I should be on the pardon list if that’s still in the works

User avatar
shpalman
Princess POW
Posts: 7189
Joined: Mon Nov 11, 2019 12:53 pm
Location: One step beyond

Re: Astronomy and Space

Post by shpalman » Fri Aug 05, 2022 12:06 pm

molto tricky

User avatar
Sciolus
Dorkwood
Posts: 1064
Joined: Mon Nov 11, 2019 6:42 pm

Re: Astronomy and Space

Post by Sciolus » Fri Aug 05, 2022 6:14 pm

Anyone got one of these self-assembly brass orreries? They look rather nice, but at 60 cm across I'm not sure where I'd put it.

(If anyone's tempted, there's a widely advertised code for £100 off.)

User avatar
Aitch
Snowbonk
Posts: 479
Joined: Tue Dec 03, 2019 9:53 am
Location: St Aines

Re: Astronomy and Space

Post by Aitch » Sat Aug 13, 2022 2:33 pm

Missed the Perseids last night (OK, I forgot) and only remembered the Big Moon this morning. Still looked pretty big, though it's hard to tell from a photograph. :(
10803-cess.jpg
10803-cess.jpg (94.93 KiB) Viewed 216 times
I take it this counts as 'Astronomy and Space'?
Some people call me strange.
I prefer unconventional.
But I'm willing to compromise and accept eccentric
.

User avatar
Gfamily
Stummy Beige
Posts: 4112
Joined: Mon Nov 11, 2019 1:00 pm
Location: NW England

Re: Astronomy and Space

Post by Gfamily » Sat Aug 13, 2022 5:36 pm

Aitch wrote:
Sat Aug 13, 2022 2:33 pm
Missed the Perseids last night (OK, I forgot) and only remembered the Big Moon this morning. Still looked pretty big, though it's hard to tell from a photograph. :(

10803-cess.jpg

I take it this counts as 'Astronomy and Space'?
The moon would have reduced the visibility of the Perseids, so it wouldn't have been a great display. They are spread over a longish period though, so keep looking while it's clear. The moon will be rising about 45 minutes later each evening, so you'll soon be able to get some dark skies before n it rises and spoils things.

The talk of the s****moon is mostly bollocks, each year we'll inevitably get one full moon where it's nearer than any other (and thus seemingly larger). However, unless you were told, you wouldn't know which full moon it is by looking at it.
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
ETA 5/8/20: I've been advised that the result was correct, it was the initial interpretation that needed to be withdrawn
Meta? I'd say so!

User avatar
Trinucleus
Catbabel
Posts: 809
Joined: Mon Nov 11, 2019 6:45 pm

Re: Astronomy and Space

Post by Trinucleus » Mon Aug 15, 2022 8:35 am

I really can't see how people can say 'look how big the supermoon is' in pictures taken with a telephoto lens

User avatar
Aitch
Snowbonk
Posts: 479
Joined: Tue Dec 03, 2019 9:53 am
Location: St Aines

Re: Astronomy and Space

Post by Aitch » Mon Aug 15, 2022 8:55 am

Trinucleus wrote:
Mon Aug 15, 2022 8:35 am
I really can't see how people can say 'look how big the supermoon is' in pictures taken with a telephoto lens
That's why I included the chimney stack.
Some people call me strange.
I prefer unconventional.
But I'm willing to compromise and accept eccentric
.

User avatar
jaap
Snowbonk
Posts: 543
Joined: Mon Nov 11, 2019 2:05 pm
Location: Netherlands
Contact:

Re: Astronomy and Space

Post by jaap » Mon Aug 15, 2022 9:35 am

Aitch wrote:
Mon Aug 15, 2022 8:55 am
Trinucleus wrote:
Mon Aug 15, 2022 8:35 am
I really can't see how people can say 'look how big the supermoon is' in pictures taken with a telephoto lens
That's why I included the chimney stack.
That does not help. Without knowing exactly how far away the chimney stack is, and how large the stack really is, such a photo leaves you as confused as Father Dougal. It is easy to make E.T.-style huge moon silhouette pictures just by being far enough away from the comparison object.

I suppose you could work out what angle you are looking up to the stack at, make an assumption about how many floors the building has, and work out the distance from that. Or work out the distance from the paralax on the three pairs of pipes. But the uncertainty in all of that as well as the uncertainty in the actual size of the stack far outweighs any apparent change of the size of the moon in the sky.

User avatar
Gfamily
Stummy Beige
Posts: 4112
Joined: Mon Nov 11, 2019 1:00 pm
Location: NW England

Re: Astronomy and Space

Post by Gfamily » Mon Aug 15, 2022 9:53 am

The full moon always looks big as it rises - it's an optical illusion thingy - probably because the brain knows that clouds near to the horizon look smaller than clouds overheard (because they are further away), so it scales them up accordingly, and the same applies when judging the size of the Moon near to the horizon.

In addition, across the summer months, the moon stays nearer to the horizon overnight, and we're more likely to be sitting out under a moonlit night in the summer.

Don't get me started on the stupid names they give to the full moon each month either - the acorn moon and the screwfix moon or whatever.
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
ETA 5/8/20: I've been advised that the result was correct, it was the initial interpretation that needed to be withdrawn
Meta? I'd say so!

User avatar
Trinucleus
Catbabel
Posts: 809
Joined: Mon Nov 11, 2019 6:45 pm

Re: Astronomy and Space

Post by Trinucleus » Mon Aug 15, 2022 1:58 pm

Aitch wrote:
Mon Aug 15, 2022 8:55 am
Trinucleus wrote:
Mon Aug 15, 2022 8:35 am
I really can't see how people can say 'look how big the supermoon is' in pictures taken with a telephoto lens
That's why I included the chimney stack.
But is it a supermoon at 30x zoom or an ordinary moon at 32x?

monkey
Dorkwood
Posts: 1349
Joined: Wed Nov 13, 2019 5:10 pm

Re: Astronomy and Space

Post by monkey » Mon Aug 15, 2022 2:02 pm

Gfamily wrote:
Mon Aug 15, 2022 9:53 am
The full moon always looks big as it rises - it's an optical illusion thingy - probably because the brain knows that clouds near to the horizon look smaller than clouds overheard (because they are further away), so it scales them up accordingly, and the same applies when judging the size of the Moon near to the horizon.
The most fun thing about the moon illusion is that the effect disappears if you look at it through your legs.

User avatar
Gfamily
Stummy Beige
Posts: 4112
Joined: Mon Nov 11, 2019 1:00 pm
Location: NW England

Re: Astronomy and Space

Post by Gfamily » Mon Aug 15, 2022 2:23 pm

monkey wrote:
Mon Aug 15, 2022 2:02 pm
Gfamily wrote:
Mon Aug 15, 2022 9:53 am
The full moon always looks big as it rises - it's an optical illusion thingy - probably because the brain knows that clouds near to the horizon look smaller than clouds overheard (because they are further away), so it scales them up accordingly, and the same applies when judging the size of the Moon near to the horizon.
The most fun thing about the moon illusion is that the effect disappears if you look at it through your legs.
As does your dignity. 😄
My avatar was a scientific result that was later found to be 'mistaken' - I rarely claim to be 100% correct
ETA 5/8/20: I've been advised that the result was correct, it was the initial interpretation that needed to be withdrawn
Meta? I'd say so!

Post Reply