Astronomy

[Iota]

It's a wonderful image.

It is indeed. And a claim on the most iconic photo ever taken, I would have thought. The subtle but global shift it created in self-awareness and perceptions of our planet still ripple out today I think.

[relm1]

For me he will be always associated with Apollo 8 and the wonderful 'Earthrise' photo (taken by Anders I think). It was Christmas 1968.
That was such an exciting time. I was 12 or 13 at the time. Apollo 8 went to the Moon but didn't land there. This was the first time anyone had seen the Earth from the Moon. Apollo 8 (Borman, Lovell, Anders) was my favourite Apollo mission.
RIP Jim Lovell:

What was it like to see a picture of the full earth for the first time?  You probably thought by 1980, you would be living on the moon.

A real hero and treasure.  I saw him at a 50th anniversary of Apollo 13 zoom live stream not long ago and he was so excited, youthful, vivacious, and jovial.  RIP Commander.  I thought he'd be around forever. 

[vandermolen]

What was it like to see a picture of the full earth for the first time?  You probably thought by 1980, you would be living on the moon.

A real hero and treasure.  I saw him at a 50th anniversary of Apollo 13 zoom live stream not long ago and he was so excited, youthful, vivacious, and jovial.  RIP Commander.  I thought he'd be around forever. 

It was amazing! I had to do an entry exam for a (high school) at that time and they asked me to write an essay about that famous photo. They offered me a place so I must have done something right! You are right that, as a boy at that time, I thought that this was the beginning of something rather than the end. 

[Elgarian Redux]

I'm way behind the curve on this, but a few days ago @owlice directed me to the Astronomy Picture of the Day' website, suggesting it might interest me. Since then I've checked every day, and this morning: 'POW!' I'm talking about today's image of the Crab Nebula. (If you're looking at this tomorrow, or later, you can still look at previous pictures if you explore the link.)

I knew the Crab Nebula as a teenager, using a home-made 4" reflector. I knew it again later during a short career as a radio astronomer in the early 1970s, as one of the most powerful radio sources in the sky. Everyone knows the standard photos of this supernova remnant. But this composite image (combining optical, X-ray and Infra-Red information), as the picture for today, is utterly gobsmacking. Do take a look. Makes the hair on my neck prickle.



By contrast, this is how I saw it as a schoolboy in 1965:

[LKB]

I'm way behind the curve on this, but a few days ago @owlice directed me to the Astronomy Picture of the Day' website, suggesting it might interest me. Since then I've checked every day, and this morning: 'POW!' I'm talking about today's image of the Crab Nebula. (If you're looking at this tomorrow, or later, you can still look at previous pictures if you explore the link.)

I knew the Crab Nebula as a teenager, using a home-made 4" reflector. I knew it again later during a short career as a radio astronomer in the early 1970s, as one of the most powerful radio sources in the sky. Everyone knows the standard photos of this supernova remnant. But this composite image (combining optical, X-ray and Infra-Red information), as the picture for today, is utterly gobsmacking. Do take a look. Makes the hair on my neck prickle.



By contrast, this is how I saw it as a schoolboy in 1965:

Thanks ER, for both the image and the perspective. 

[relm1]

I'm way behind the curve on this, but a few days ago @owlice directed me to the Astronomy Picture of the Day' website, suggesting it might interest me. Since then I've checked every day, and this morning: 'POW!' I'm talking about today's image of the Crab Nebula. (If you're looking at this tomorrow, or later, you can still look at previous pictures if you explore the link.)

I knew the Crab Nebula as a teenager, using a home-made 4" reflector. I knew it again later during a short career as a radio astronomer in the early 1970s, as one of the most powerful radio sources in the sky. Everyone knows the standard photos of this supernova remnant. But this composite image (combining optical, X-ray and Infra-Red information), as the picture for today, is utterly gobsmacking. Do take a look. Makes the hair on my neck prickle.



By contrast, this is how I saw it as a schoolboy in 1965:

That is very cool!  I thought the photo was a painting.  And you have excellent penmanship. 

[Elgarian Redux]

That is very cool!  I thought the photo was a painting.

So did I at first. The white areas actually look as if they have 'handling' don't they, as though put on with a brush. Nature catching up on Art, as Whistler would have said.

And you have excellent penmanship. 

That was 60 years ago. You should see it now! Scrappy stuff.

[krummholz]

I'm way behind the curve on this, but a few days ago @owlice directed me to the Astronomy Picture of the Day' website, suggesting it might interest me. Since then I've checked every day, and this morning: 'POW!' I'm talking about today's image of the Crab Nebula. (If you're looking at this tomorrow, or later, you can still look at previous pictures if you explore the link.)

I knew the Crab Nebula as a teenager, using a home-made 4" reflector. I knew it again later during a short career as a radio astronomer in the early 1970s, as one of the most powerful radio sources in the sky. Everyone knows the standard photos of this supernova remnant. But this composite image (combining optical, X-ray and Infra-Red information), as the picture for today, is utterly gobsmacking. Do take a look. Makes the hair on my neck prickle.

Awesome picture! I wonder why it's the "Picture of the Day" now though. I've been showing that picture, or a nearly identical one, to my astronomy students for a few years now.

For those who don't know, the Crab Nebula is the remnant of a Type II supernova, a massive star that exploded (the supernova was recorded by Chinese astronomers in 1054), leaving behind a neutron star, a compact object that's so dense that it weighs, in Carl Sagan's famous words, "a mountain per teaspoonful". The emissions from the accretion disk around the neutron star, as well as the pair of "bipolar jets" emanating at right angles to the disk, are one of the true beauties of nature.

Neutron stars are typically detected as pulsars, usually radio sources that blink on and off at regular intervals, often more than once per second. But the Crab pulsar can actually be seen blinking in visible light as well - somewhere I have a picture of that.

[Elgarian Redux]

Awesome picture! I wonder why it's the "Picture of the Day" now though. I've been showing that picture, or a nearly identical one, to my astronomy students for a few years now.

I don't think a 'Picture of the Day' has to be a recent picture. It's just recently selected. I've no idea what criteria are used for selection.

This one, however, was entirely new to me, personally.

[LKB]

I don't think a 'Picture of the Day' has to be a recent picture. It's just recently selected. I've no idea what criteria are used for selection.

This one, however, was entirely new to me, personally.

This is ( imho ) scientific exposition at its best.

M1 has been famous among astronomers for nearly two centuries, and surely must be one of the first nebulae that any young astronomer will encounter as they explore their new hobby/avocation.

A new perspective on such a celebrated object... I can hardly conceive of a more rewarding result.

[relm1]

My new picture is the biggest I've ever taken!  5 nights of imaging and nearly a terabyte of images went in to create this picture of North America Nebula!  It is 2,200 ly away and spans at least 50 ly.  My thinking is that dark patch on the lower right is in front of the nebula and so dense, it blocks out the stars behind it.  Notice how many more stars are visible everywhere else.  There is probably a star cluster behind the dark cloud that is blasting away the walls of the nebula.  Quite stunning to see something so massive and living, pulsing with energy and activity at multiple levels.

[steve ridgway]

There is probably a star cluster behind the dark cloud that is blasting away the walls of the nebula.

Oh yes, the edges of the cloud look like they're being eaten away. Fantastic image!

[Elgarian Redux]

My new picture is the biggest I've ever taken!  5 nights of imaging and nearly a terabyte of images went in to create this picture of North America Nebula!  It is 2,200 ly away and spans at least 50 ly.  My thinking is that dark patch on the lower right is in front of the nebula and so dense, it blocks out the stars behind it.  Notice how many more stars are visible everywhere else.  There is probably a star cluster behind the dark cloud that is blasting away the walls of the nebula.  Quite stunning to see something so massive and living, pulsing with energy and activity at multiple levels.

Sir, I salute you. The picture is utterly magnificent. Thank you for posting it.

[relm1]

Oh yes, the edges of the cloud look like they're being eaten away. Fantastic image!

Thank you kindly!

[relm1]

Sir, I salute you. The picture is utterly magnificent. Thank you for posting it.

Much appreciated!  Thank you!

[krummholz]

My new picture is the biggest I've ever taken!  5 nights of imaging and nearly a terabyte of images went in to create this picture of North America Nebula!  It is 2,200 ly away and spans at least 50 ly.  My thinking is that dark patch on the lower right is in front of the nebula and so dense, it blocks out the stars behind it.  Notice how many more stars are visible everywhere else.  There is probably a star cluster behind the dark cloud that is blasting away the walls of the nebula.  Quite stunning to see something so massive and living, pulsing with energy and activity at multiple levels.

Awesome picture! I think you are correct about the dark patch - a denser part of the nebula and one with no hot young stars nearby to make the hydrogen glow. The NA Nebula is known to be an emission nebula (the red color is emissions from hydrogen gas, mainly at the famous H-alpha wavelength), but what caught my attention were the bluish patches. I see those in some photos of the nebula and not in others. I'm not sure whether it's an artifact or actual Rayleigh scattering of blue (short wavelength) light by small dust particles in the nebula, the mechanism that makes a reflection nebula.

[LKB]

Awesome picture! I think you are correct about the dark patch - a denser part of the nebula and one with no hot young stars nearby to make the hydrogen glow. The NA Nebula is known to be an emission nebula (the red color is emissions from hydrogen gas, mainly at the famous H-alpha wavelength), but what caught my attention were the bluish patches. I see those in some photos of the nebula and not in others. I'm not sure whether it's an artifact or actual Rayleigh scattering of blue (short wavelength) light by small dust particles in the nebula, the mechanism that makes a reflection nebula.

PHENOMENAL image, bravissimo!

[relm1]

Awesome picture! I think you are correct about the dark patch - a denser part of the nebula and one with no hot young stars nearby to make the hydrogen glow. The NA Nebula is known to be an emission nebula (the red color is emissions from hydrogen gas, mainly at the famous H-alpha wavelength), but what caught my attention were the bluish patches. I see those in some photos of the nebula and not in others. I'm not sure whether it's an artifact or actual Rayleigh scattering of blue (short wavelength) light by small dust particles in the nebula, the mechanism that makes a reflection nebula.

Keep in mind (and I failed to mention this), the nebula in my picture is narrow band so RGB are attributes of various narrowband wavelengths.  The first try at processing, I gave Ha red which as you state, the region is very heavy in that wavelength, so the image was overall very reddish (still beautiful but different).  I checked my notes again and saw Hubble uses Sii (Sulphur II=Red), Ha (Hydrogen Alpha=Green), Oiii (Oxygen III=Blue) which is what I used here.  The stars are true color and from the RGB images.  Notice the very black spots above center left.  Those caught my eye and I wonder what is going on there? 

[relm1]

PHENOMENAL image, bravissimo!

Thank you kindly!

[steve ridgway]

Notice the very black spots above center left.  Those caught my eye and I wonder what is going on there?

If not image artefacts I was wondering if those might be dense remnants of the original cloud such as Bok globules.