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

astroanarchy.blogspot.com

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

#92
post #36
post #33

Earlier quoted context omitted.

In astrophotography there's (almost) no such thing as "natural". It's definitely an aesthetic, but it's based on "real" data.

It can be true that it's both based on real data and that there is an aggressive amount of post-sharpening applied.

This is true, but it's also true that making faint features visible (like the dark, dusty regions) often requires the use of local contrast, sharpening, and masks.

Also, in the case of this specific image, I think it's important to note just how deep the images are - they're processed for high resolution in the individual components, so the mosaic has an absolutely huge resolution. When downscaled to look at the whole thing zoomed out, that might give some of the impression of over-sharpness.

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

#93
post #84

On a camera in manual mode if you increase the exposure time, you must compensate the increased amount of light coming to the sensor by decreasing the aperture or the ISO. Can anybody please explain, how is it possible to have such a long exposure without overexposing the image?

Note that these images are made from many exposures that are then processed and combined, and the total exposure time is given. The individual exposure times were probably long, but I'm guessing on the order of minutes, not hours. (Actually, if you photograph stars with an exposure time that is too long, then you get star trails in the image.)

Trails appear very quickly, at focal lengths of around 20mm (typical dslr kit lens) they are obvious in 20-30 seconds, with a 100mm lens (start of telephoto range) they are obvious in 3-5 seconds. This of course depends on the res of your camera (I shoot with an 8MP and a 24MP).

To get rid of the trails you need a tracking mount. The better the mount the smoother and longer it tracks. Astrophotography is expensive...

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

#94
post #84

On a camera in manual mode if you increase the exposure time, you must compensate the increased amount of light coming to the sensor by decreasing the aperture or the ISO. Can anybody please explain, how is it possible to have such a long exposure without overexposing the image?

Note that these images are made from many exposures that are then processed and combined, and the total exposure time is given. The individual exposure times were probably long, but I'm guessing on the order of minutes, not hours. (Actually, if you photograph stars with an exposure time that is too long, then you get star trails in the image.)

> if you photograph stars with an exposure time that is too long, then you get star trails in the image

He was using a tracking mount. At 200mm you can't image for more than a few seconds without trailing.

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

#95

On a camera in manual mode if you increase the exposure time, you must compensate the increased amount of light coming to the sensor by decreasing the aperture or the ISO. Can anybody please explain, how is it possible to have such a long exposure without overexposing the image?

Astrophotography is less like photography and more like scientific data acquisition.

To specifically answer your question though, this is "1250 hours of exposures" and not "a 1250 hour exposure".

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

#97
post #82

Earlier quoted context omitted.

I agree with your larger premise, but: > Can you see the Milkyway? No, not really This is not my experience. I have seen the Milky Way very clearly from a few locations in the US. None are particularly remote -- all are just a few hours drive from the large cities I've lived in. Winter months are clearer than summer.

Yeah I agree. Not only have I seen the milky way, but I've seen andromeda with my naked eye from the right place on the right night, within a day's drive from very populated cities.

+1. I’ve not seen it for 10 years (since I’ve lived in the United States) but growing up in New Zealand, looking up at the Milky Way with your naked eye, it’s definitely clear the increased density of stars. Doesn’t look anything like photos, but very beautiful.

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

#98
post #40

When I look at this, it is hard to believe that life (and intelligent life) only exist on planet Earth... Very hard to believe.

There are roughly 10^23 stars in the observable universe. We really have no idea how likely intelligent life is to evolve. It could be 1/10^10 per star, in which case intelligent life would be a fairly typical thing (dozens in the milky way), or it could be just 1/10^100, in which case we could be the only ones. Unlikelihoods can compound very quickly.

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

#99
post #26
post #6

Wow amazing work! The scale of this project reminds me of another photographer's five year project of creating a 2.5 gigapixel photo of Orion: https://orion2020v5b.spaceforeverybody.com/

This is fantastic. I immediately wondered how he managed to seamlessly mosaic together what is surely hundreds of images and thousands of subs. Here are the details: https://space4everybody.com/processing-details/ And equipment: https://space4everybody.com/technical-details-equipment/ Nothing too fancy (in astrophotography relative terms). A decent refractor and mono camera (such parameters have come down in price by…

Unfortunately they don't seem to have a link to the final "full-res" image. I'd love to put that with my collection of other massive-res images. My screensaver pans between random spots on massive images in a folder.

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

#100
post #75

Earlier quoted context omitted.

Thats not hard to believe once you understand how unprobable life seems to be and especially in the very long term. The universe is a very violent place and cosmic events act as great filters all the time.

Then again, this photo mosaic spans just one arm of one galaxy in the visible universe.

We know that life only emerges in very specific conditions, that most planets do not have. We also know that even in very stable Earth, we have had billions and billions of species that developed and disappeared and we now only have a single specie with technological capabilities - and for a very short time at that, all things considered.

If the universe is 'rich in life', most of it is probably micro-organisms that get wiped out every now and then by drastic changes on the planetary scale.

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