Space

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Replies

  • cee134
    cee134 Posts: 33,711 Member
    Space farming is now officially a thing.

    https://www.youtube.com/watch?v=c1Gxn_nfgWA
  • LittleLionHeart1
    LittleLionHeart1 Posts: 3,655 Member
    edited December 2016
    cee134 wrote: »
    Space farming is now officially a thing.

    https://www.youtube.com/watch?v=c1Gxn_nfgWA

    Coolness! Thank you. Thats a keeper!
    The Farmers Daughter.
  • cee134
    cee134 Posts: 33,711 Member
    Neil Armstrong's left extravehicular glove with sewn-on cuff checklist itemizing his duties as LMP Commander once on the surface of the moon.

    g2pogbitdfzj.jpg
  • Timshel_
    Timshel_ Posts: 22,834 Member
    The latest USAF tactical satellite will be launched tonight. Wish I could be there to see it live. That has to be AMAZING.
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  • MelodyandBarbells
    MelodyandBarbells Posts: 7,724 Member
    Anyone else only see @thesunmoonandstars posts when she's quoted?

    Also, I have a question about "seeing" the Milky Way galaxy. Since that's our galaxy, how does one see it? The way I understand it, it would be like seeing earth. Since we're on planet earth, it wouldn't look like a sphere from here, right?
  • RunHardBeStrong
    RunHardBeStrong Posts: 33,069 Member
    Timshel_ wrote: »
    The latest USAF tactical satellite will be launched tonight. Wish I could be there to see it live. That has to be AMAZING.

    I agree. I would love to see a live launch of any sort.
  • Unknown
    edited December 2016
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  • MelodyandBarbells
    MelodyandBarbells Posts: 7,724 Member
    @JaneiR36 wrote: »
    Anyone else only see @thesunmoonandstars posts when she's quoted?

    Also, I have a question about "seeing" the Milky Way galaxy. Since that's our galaxy, how does one see it? The way I understand it, it would be like seeing earth. Since we're on planet earth, it wouldn't look like a sphere from here, right?

    It's like taking a picture of your house while you're inside it. You won't see the entire thing like the way you can see the Andromeda galaxy. It's like looking at an inside edge of the milkyway

    An inside edge. Wow. Love this thread! Thank you for responding :). Considering that earth is rotating, do we keep facing the same segment of the rest of the galaxy, or does it vary?
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    JaneiR36 wrote: »
    Also, I have a question about "seeing" the Milky Way galaxy. Since that's our galaxy, how does one see it? The way I understand it, it would be like seeing earth. Since we're on planet earth, it wouldn't look like a sphere from here, right?

    The galaxy is way less like a sphere than the Earth, it's closer to a dinner plate, but bulging in the middle. At least that's the current understanding. But it doesn't look like a circle from inside, it looks more like a thick line across the sky.

    milky-way-you-are-here.jpg

    I've posted this before but it's probably useful right now. This is the Milky Way from Slate Peak in the North Cascades. The camera is more sensitive than the eye, so it's a little bit dimmer and it's less colorful too, when you're standing there.

    24836980445_5deb5f991b_o_d.jpg
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  • NorthCascades
    NorthCascades Posts: 10,968 Member
    @PlaydohPants and @KeithMarcus

    Let's go with a really basic analogy - but let's also stick with our space theme.

    The sun is a star. It's not the biggest or the brightest start.

    solar_system_poster.jpg

    But it sure looks brighter than all the other stars.

    Light comes from stars, and it goes in every direction, like this:

    85abdf77cd294842_org.jpg

    The closer you are to any light source, the more light will reach you. The further you are, the less light. Because tiny differences in angle get multiplied over distance. You can see how the beams spread out, they'll miss things that are far away.

    You see light. Your eyes have lenses that gather it over a wide area and focus it onto a small area packed with light-sensitive cells.

    rods-and-cones.jpg

    A camera works the same way. But it's more sensitive - it "wastes" fewer incoming photons to inefficiency, so it requires fewer of them to recognize an image. The lenses people use for astrophotography are much larger (as a ratio of aperture width to optical length) than the eye, so they're able to gather more light.

    People can do math, but we built calculators that can do it better. People can see, but we built cameras that can see better.
  • Unknown
    edited December 2016
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  • NorthCascades
    NorthCascades Posts: 10,968 Member
    I don't think I explained that very well at all. If you were able to make any sense of it, my hat's off to you.
  • MrStabbems
    MrStabbems Posts: 3,110 Member
    astrophotography is a great hobby but gets expensive fast! my mount for my telescope cost me close to £1k and that was a cheap one!
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  • NorthCascades
    NorthCascades Posts: 10,968 Member
    Another thing, if anybody is interested in the physics of light and vision.

    Here are some pictures of a 50 mm lens at different apertures:

    aperture.jpg

    You can plainly see that more light will pass through the lens at f/1.8 (first) than at f/22 (last). Smaller numbers mean a bigger opening, and more light gathering power - more brightness.

    Your eyes work the same way. Your pupils dilate when it's dark, and when you're under the influence of certain drugs. They close down when it's bright out. That's why you can see well enough to walk under a full moon, or at noon at the beach. The lens in the pics above can open to f/1.8 and it can close to f/22, it can't get brighter or darker than that.

    A 50 mm f/1.8 lens like this one costs about $100. A 50 mm f/1.4 lens is almost 2x brighter, weighs almost 2x as much, and costs $400. A 50 mm f/1.2 lens is brighter, heavier, and costs $1,500.

    I don't know which one is most similar to human vision, but people can't go to the store and buy cat eyes. You sort of can do that with cameras. That's a huge part of why photos of the Milky Way look different than standing outside looking at it.
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    I don't think I explained that very well at all. If you were able to make any sense of it, my hat's off to you.

    Did you take advantage of a different kind of space last night Eeyore?

    The snow must have frozen my brain, 'cause I'm not following?
  • MrStabbems
    MrStabbems Posts: 3,110 Member
    also most pictures of the MW will be significantly processed (stacking etc). atleast I'm my experience. A lot of photographers also play with hues
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    Right, the pictures are generally enhanced and I'm sure @NorthCascades can shed more light on how since I don't know much about photography. But when you look with the naked eye you can't pick up the dim light like a camera can. At least, it looks dim because it's so far away.

    You'll never see a really good photo of the Milky Way that hasn't been edited. Probably more than a little. Mostly taken with a specialty lens, too, because there's only so much you can do in the computer.

    I don't like the term enhanced at all, even though it's completely accurate.

    The way people see is amazing, and it's pretty *kitten* relevant to us. But it's not "the" truth, it's "a" truth. Mantis shrimp can see colors we can't, because their brains process visual information differently from ours.

    Really good cameras are designed to make dull photos. They're flat, and not especially colorful, because that's how they preserve the most data. Making them more contrasty means throwing data away, bringing darker values closer to 0 and brighter ones closer to 1, fewer values repeated more times. Exactly how much is a matter of taste, so best to just record everything. All of the same kind of stuff happens when film gets developed.

    This is "Moonrise Over Hernandez, New Mexico" by Ansel Adams. He worked on the negative for ten years before he released a print!

    ansel-adams-moonrise-hernandez-new-mexico-1344352981_b.jpg

    People have this idea that photos are an objective record, or sometimes they're doctored. I think it's more fair to say it's a different way of processing visual information.
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  • NorthCascades
    NorthCascades Posts: 10,968 Member
    I thought that's what you had to have meant, because whenever I'm confused I assume someone is talking dirty to me. But I wasn't sure.

    I did!! :smile:
  • I captured this image of the November "Supermoon."


    q5p3xre1xsmi.jpg
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  • MelodyandBarbells
    MelodyandBarbells Posts: 7,724 Member
    JaneiR36 wrote: »
    Also, I have a question about "seeing" the Milky Way galaxy. Since that's our galaxy, how does one see it? The way I understand it, it would be like seeing earth. Since we're on planet earth, it wouldn't look like a sphere from here, right?

    The galaxy is way less like a sphere than the Earth, it's closer to a dinner plate, but bulging in the middle. At least that's the current understanding. But it doesn't look like a circle from inside, it looks more like a thick line across the sky.

    milky-way-you-are-here.jpg

    I've posted this before but it's probably useful right now. This is the Milky Way from Slate Peak in the North Cascades. The camera is more sensitive than the eye, so it's a little bit dimmer and it's less colorful too, when you're standing there.

    24836980445_5deb5f991b_o_d.jpg

    This is a really gorgeous picture, but I can't quite make out the dinner plate? Could you give me an idea what portion of it is captured in your picture? And thank you, you've been so patient with your explanations, and my questions are really elementary.
  • I captured this image of the November "Supermoon."


    q5p3xre1xsmi.jpg

    Beautiful pic!

    Thank you!
  • I took this pic of the Orion Nebula last winter.


    9rx4kqropfi4.jpg