Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky • Hacker News Board

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#11

Post by enriquto » Wed, Mar 17, 2021, 2:50 PM UTC

amelius wrote: post #9

dr_orpheus wrote: post #8

Earlier quoted context omitted.

They are synthesized, from the article "Image in mapped colors from the light emitted by an ionized elements, hydrogen = green, sulfur = red and oxygen = blue."

What do the real colors look like?

just look up to the sky at night. They are so dim that you cannot really distinguish their hue.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#12

Post by amelius » Wed, Mar 17, 2021, 2:53 PM UTC

enriquto wrote: post #11

amelius wrote: post #9

Earlier quoted context omitted.

What do the real colors look like?

just look up to the sky at night. They are so dim that you cannot really distinguish their hue.

When I look up to the sky at night I just see reflections of the lights emitted by my city. It often is an orange glow.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#13

Post by elteto » Wed, Mar 17, 2021, 2:58 PM UTC

amelius wrote: post #9

dr_orpheus wrote: post #8

Earlier quoted context omitted.

They are synthesized, from the article "Image in mapped colors from the light emitted by an ionized elements, hydrogen = green, sulfur = red and oxygen = blue."

What do the real colors look like?

Hard to tell without being closer :) Nebulae might not even emit that strongly in the spectrum that we humans can see. A lot of these pictures are taken with special narrowband filters that isolate wavelengths for specific components, such as Oxygen or Hydrogen. Then these narrowband images are combined and assigned to the R, G, B channels. A popular palette is the "Hubble Palette" because, well, that is what the Hubble uses.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#14

Post by nsilvestri » Wed, Mar 17, 2021, 2:58 PM UTC

amelius wrote: post #9

dr_orpheus wrote: post #8

Earlier quoted context omitted.

They are synthesized, from the article "Image in mapped colors from the light emitted by an ionized elements, hydrogen = green, sulfur = red and oxygen = blue."

What do the real colors look like?

Depends on the filter used. I am assuming the author is using one of these hydrogens (probably Hα) and O-III and S-II. Each of these black-and-white images with this filter are used as the data for a single RGB channel in an image. Their wavelengths are, and would like like to the naked eye [1]:

Hα (656 nm) bright red

Hβ (486 nm) deep blue

O-III (496 nm and 501 nm) greenish blue to green

S-II (672 nm) deeper red

The color mapping the author uses is called the Hubble Space Telescope pallet, where hydrogen = green, sulfur = red, and oxygen = blue.

[1] http://pages.cs.wisc.edu/~yetkin/code/wavelength_to_rgb/wave...

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#15

Post by dylan604 » Wed, Mar 17, 2021, 2:58 PM UTC

amelius wrote: post #9

dr_orpheus wrote: post #8

Earlier quoted context omitted.

They are synthesized, from the article "Image in mapped colors from the light emitted by an ionized elements, hydrogen = green, sulfur = red and oxygen = blue."

What do the real colors look like?

Depends on what you mean by real colors. The light is so faint, that human eyes cannot make it out. However, long exposure photography with a CMOS sensor will bring out colors without any filters. Are those the real colors? There are tons of examples of these types of shots. Search for The World At Night (TWAN) for some great examples

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#16

Post by cozzyd » Wed, Mar 17, 2021, 2:58 PM UTC

Can I buy a large print of this somewhere?

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#17

Post by JohnJamesRambo » Wed, Mar 17, 2021, 3:01 PM UTC

amelius wrote: post #12

enriquto wrote: post #11

Earlier quoted context omitted.

just look up to the sky at night. They are so dim that you cannot really distinguish their hue.

When I look up to the sky at night I just see reflections of the lights emitted by my city. It often is an orange glow.

This is too dystopian this early in the morning.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#18

Post by ACAVJW4H » Wed, Mar 17, 2021, 3:04 PM UTC

> My observatory is located in the very center of the city Oulu in Finland. Due to massive Light Pollution I mainly do ...

Well I guess most of us live in filthy cesspools of light. Seriously I wonder what humanity misses out on. I think we would have been a much better species if only we could see our place in the universe every night.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#19

Post by ACAVJW4H » Wed, Mar 17, 2021, 3:09 PM UTC

thanatos519 wrote: post #3

What do I have to do to get the full-size image? The 7000x1300 pixel image is pretty nice, but I was thinking of making a 1440dpi print on 4 sheets of A3+.

I had the urge to print as well. I doubt he'll be interested in giving away this masterpiece, atleast for an affordable price. I'll mail and ask; he might offer a print service maybe.

Re: Milky Way, 12 years, 1250 hours of exposures and 125 x 22 degrees of sky

#20

Post by lolptdr » Wed, Mar 17, 2021, 3:14 PM UTC

mnw21cam wrote: post #10

ClosedPistachio wrote: post #2

The full panorama is spectacular: https://1.bp.blogspot.com/-LK-I6WIOp8w/YE3ejvMEc8I/AAAAAAAAS...

That's not the full panorama. Try https://1.bp.blogspot.com/-TqRxEAjrDYI/YFCLF-H8K3I/AAAAAAAAS... instead.

Damn, this is impressive. Wish there were more annotations of other notable sky objects in addition to what's shown.