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  1. #221
    Join Date
    Feb 2008
    Location
    New Bern, NC unless it's a home football game then I'm grilling on Devil's Alley
    Quote Originally Posted by DevilHorse View Post
    Of course I haven't seen the details of this telescope, but there are some basic limiting factors of earth based, optical telescopy:

    1) light pollution (mountains of Chile are good, but it gets worse all of the time)

    2) Glass is still a fluid, not a solid. (did you ever see 100 year old windows?) No matter how you polish it, it will slowly flow out of focus. Remember the first Hubble Telescope lens? It is hard to do right.

    3) The Atmosphere changes with wind, uneven clouds (jet trails), pollution, ozone, and temperature. Stars twinkle for a reason. It hurts optical viewing and stability; and it gets windy in the mountains; even small telescopes shake.

    4) Elon Musk, and his ilk, and his ongoing pollution of the heavens of satellites and space junk. Probably integrated out, but limiting nonetheless.

    I recall a while ago reading an article suggesting that a 200" optical telescope was about as big an optical telescope that could be built with a single lens. Of course, multiple mirror, optical lens telescopes have been built that try to get past these limitations:
    https://www.google.com/imgres?imgurl...MygDegUIARCfAg

    Optical telescopes are the most viscerally enjoyable and accessible, but they (obviously) still cover only a fraction of the EM spectrum. Since it has been determined that most of what is out there is Dark Matter, there are so many more structures out there to find (without getting a crick in your neck). But I digress.

    Larry
    DevilHorse
    All true, but it is still cool!
    Q "Why do you like Duke, you didn't even go there." A "Because my art school didn't have a basketball team."

  2. #222
    Quote Originally Posted by CameronBornAndBred View Post
    All true, but it is still cool!
    Indeed.

    On closer inspection...

    These are mirrors, not a lens. This allows greater stability and support to the reflective elements (less flow).
    There are 6 mirrors around a central element, and they are 331 inches each; lots of light gathering power/area.
    They are not fixed and will move to minimize atmospheric effects (twinkling stars).

    Obvious limits would be that nights limit the length of exposures each day. Hubble doesn't have this problem.

    Here are some links:
    https://www.gmto.org/overview/
    https://www.cfa.harvard.edu/gmt/features

    Larry
    DevilHorse

  3. #223
    Note the clouds on this picture above this 21 meter bluff from Curiosity:
    https://twitter.com/i/status/1373394638288121864

    The clouds are surmised to be water vapor/ice. I'd note that we don't see clouds on Mars from above, but we can see structure like this from below. Planet based observations are just so much more revealing.

    Larry
    DevilHorse

  4. #224
    Perhaps a little off the topic, but if you are interested in Astronomy then you have to be interested in what is going on with our own planet earth.
    The recently activated Iceland Fagradalsfjall volcano is absolutely spectacular and mesmerizing.

    This isn't a volcano on Io or Enceladus, but it is fascinating and tame enough for a close-up view.
    They love their volcano's in Iceland, so they approach them like they do on the Big Island of Hawaii.

    Here is a LIVE webcam of what is going on at the volcano, with a view of the whole caldera and the spatter cone:
    https://www.ruv.is/frett/2021/03/20/...a-eldstodvunum

    Click on the expanded view, when not using your monitor, and let this be the best screen saver you've had in a while.
    Yes, better than the salt water fish aquarium, or the pin-ball machine, if that is even possible.

    You can even see spurts of lava in unexpected places if you look hard enough. And at night the whole mound lights up with infra-red!

    If you want some closer looks at what is happening at the spatter cone, put "volcano" into your search bar in twitter. There is one amazing loop of volcano watchers close up when a partial cone collapse happens.
    For comedy, see if you can find the guy who is roasting hot dogs on the lava; then he uses ketchup?! Someone send him some Gulden's Spicy Brown please.


    Larry
    DevilHorse

  5. #225
    Join Date
    Feb 2008
    Location
    New Bern, NC unless it's a home football game then I'm grilling on Devil's Alley
    Here's some cool drone footage of said volcano. Hard to tell, but I'm not sure the drone(s) actually survived.

    Q "Why do you like Duke, you didn't even go there." A "Because my art school didn't have a basketball team."

  6. #226
    Join Date
    Feb 2008
    Location
    New Bern, NC unless it's a home football game then I'm grilling on Devil's Alley
    Second vid.

    [/VIDEO]
    Q "Why do you like Duke, you didn't even go there." A "Because my art school didn't have a basketball team."

  7. #227
    Join Date
    Feb 2007
    Location
    Steamboat Springs, CO
    Quote Originally Posted by DevilHorse View Post

    Here is a LIVE webcam of what is going on at the volcano, with a view of the whole caldera and the spatter cone:
    https://www.ruv.is/frett/2021/03/20/...a-eldstodvunum


    Larry
    DevilHorse
    Had this up for a couple of hours. The lava flow has expanded by a factor of several times since I tuned in. Maybe its cyclical.

    Gary
    Sage Grouse

    ---------------------------------------
    'When I got on the bus for my first road game at Duke, I saw that every player was carrying textbooks or laptops. I coached in the SEC for 25 years, and I had never seen that before, not even once.' - David Cutcliffe to Duke alumni in Washington, DC, June 2013

  8. #228
    Quote Originally Posted by sagegrouse View Post
    Had this up for a couple of hours. The lava flow has expanded by a factor of several times since I tuned in. Maybe its cyclical.

    Gary
    Did you see the scene where the splatter cone spilled over and started a flow toward the group of on-lookers? I estimated they (about 200 people) were standing 1-1.5 miles from the splatter cone when it happened. Very dramatic. The lava spilled orthogonal to the people, but then came toward them and slowed.

    https://twitter.com/i/status/1374065338430590979


    <getting the picture framed in this note is a skill I haven't perfected yet. Should be a sandbox to play in.>

    You can hear screams and laughs. Sounds like an amusement park.

    Larry
    DevilHorse

  9. #229

    Next Asteroid To Hit The Earth

    Does an asteroid hitting the earth keep you up at night? Ever? On rare occassions, it does for me.

    Well, some information from NASA has come out this week:
    https://www.nasa.gov/feature/jpl/nas...100-plus-years
    Depending on the news source, it has been interpreted as "NASA does not see any Asteroids hitting the earth for the next 100 years."

    Of course, this does not cover those objects that are unknown, like the ones that come at us from the direction of the sun that we can't see until they are upon us at the last minute. But they are usually pretty small.

    NASA tracks Near Earth Objects (NEOs) closely, so there is active awareness of what is out there.

    So, you think that we only have a program of rovers and the occassional space station visit? Think again.

    We will also have an Asteroid perturbing space mission coming up soon. Seems really interesting.
    https://youtu.be/ADFlYxXePfo

    Here is a pointer to the DART space mission.
    https://www.nasa.gov/planetarydefense/dart

    I can sleep better already.

    Larry
    DevilHorse

  10. #230
    Join Date
    Feb 2008
    Location
    New Bern, NC unless it's a home football game then I'm grilling on Devil's Alley
    Quote Originally Posted by DevilHorse View Post
    Well, some information from NASA has come out this week:
    https://www.nasa.gov/feature/jpl/nas...100-plus-years
    Depending on the news source, it has been interpreted as "NASA does not see any Asteroids hitting the earth for the next 100 years."
    Where's the fun in that? Borrrrrringgggg!
    Q "Why do you like Duke, you didn't even go there." A "Because my art school didn't have a basketball team."

  11. #231
    Join Date
    Feb 2007
    Location
    Washington, DC area
    We never know when the next interstellar probe will show up, though!

    -jk

  12. #232

    Partial Credit

    Partial credit for enabling the ship that has been clogging the Suez Canal has been given to the unusual high tide provided by the Supermoon!
    In honor of that, here is a cartoon from Xkcd in the Astronomy forum:

    supermoon2.jpg

    Larry
    DevilHorse

  13. #233

    Helicopter on Mars

    This week we expect to see the Mars Perseverance Helicopter, Ingenuity, get some action.
    It is partially deployed, with its legs out, but not yet on the surface while its batteries are charging.
    It will soon be left all by its lonesome on the surface and test flown later this week.

    Follow the details on the Perseverance Twitter feed:
    https://twitter.com/NASAPersevere

    and the Ingenuity Engineer's Blog:
    https://mars.nasa.gov/technology/hel...-cold-on-mars/

    Larry
    DevilHorse

  14. #234
    Join Date
    Feb 2007
    Location
    Washington, DC area
    Quote Originally Posted by DevilHorse View Post
    This week we expect to see the Mars Perseverance Helicopter, Ingenuity, get some action.
    It is partially deployed, with its legs out, but not yet on the surface while its batteries are charging.
    It will soon be left all by its lonesome on the surface and test flown later this week.

    Follow the details on the Perseverance Twitter feed:
    https://twitter.com/NASAPersevere

    and the Ingenuity Engineer's Blog:
    https://mars.nasa.gov/technology/hel...-cold-on-mars/

    Larry
    DevilHorse
    Fun.

    And thanks for keeping us up to date!

    -jk

  15. #235
    The Mars Helicopter is standing on its own.
    https://twitter.com/NASAJPL/status/1378513754241961985

    Now, checking that it can hold its charge overnight, then taking it for a spin this week.

    Larry
    DevilHorse

  16. #236
    Quote Originally Posted by DevilHorse View Post
    Perhaps a little off the topic, but if you are interested in Astronomy then you have to be interested in what is going on with our own planet earth.
    The recently activated Iceland Fagradalsfjall volcano is absolutely spectacular and mesmerizing.

    This isn't a volcano on Io or Enceladus, but it is fascinating and tame enough for a close-up view.
    They love their volcano's in Iceland, so they approach them like they do on the Big Island of Hawaii.

    Here is a LIVE webcam of what is going on at the volcano, with a view of the whole caldera and the spatter cone:
    https://www.ruv.is/frett/2021/03/20/...a-eldstodvunum

    Click on the expanded view, when not using your monitor, and let this be the best screen saver you've had in a while.
    Yes, better than the salt water fish aquarium, or the pin-ball machine, if that is even possible.

    You can even see spurts of lava in unexpected places if you look hard enough. And at night the whole mound lights up with infra-red!

    If you want some closer looks at what is happening at the spatter cone, put "volcano" into your search bar in twitter. There is one amazing loop of volcano watchers close up when a partial cone collapse happens.
    For comedy, see if you can find the guy who is roasting hot dogs on the lava; then he uses ketchup?! Someone send him some Gulden's Spicy Brown please.


    Larry
    DevilHorse
    Here is an alternate view of the Iceland Volcano. This one has audio. White noise to calm you down after a long tournament.
    https://www.youtube.com/watch?v=ksVlz1qIaJM

    Apparently a new fissure has opened on the side of the volcano. Nicknamed "Flo" or "Carrie Fissure" (Bobby Fissure is apparently too american..).

    Larry
    DevilHorse

  17. #237
    Quote Originally Posted by DevilHorse View Post
    The Mars Helicopter is standing on its own.
    https://twitter.com/NASAJPL/status/1378513754241961985

    Now, checking that it can hold its charge overnight, then taking it for a spin this week.

    Larry
    DevilHorse
    Article with details on what to expect this week from Ingenuity and when.
    https://www.forbes.com/sites/jamieca...rForbesScience

    Maybe this weekend..
    If a lot of things go right, it will 'scout' ahead of Percy. Now that would be neat.

    No explanation of what Percy is doing while Ingenuity is doing all of this 'waiting' and preparation work. Obviously Percy has to stay nearby so it can observe Ingenuity's status during/after test flights.

    Larry
    DevilHorse

  18. #238
    Quote Originally Posted by DevilHorse View Post
    Article with details on what to expect this week from Ingenuity and when.
    https://www.forbes.com/sites/jamieca...rForbesScience

    Maybe this weekend..
    If a lot of things go right, it will 'scout' ahead of Percy. Now that would be neat.

    No explanation of what Percy is doing while Ingenuity is doing all of this 'waiting' and preparation work. Obviously Percy has to stay nearby so it can observe Ingenuity's status during/after test flights.

    Larry
    DevilHorse
    Thanks for the link! Fascinating. But rather than spend $80 million on Ingenuity (and it may well crash and it will be "totaled"), couldn't they have just bought a $900 drone online and attach a GoPro to it??

  19. #239
    Quote Originally Posted by duke79 View Post
    Thanks for the link! Fascinating. But rather than spend $80 million on Ingenuity (and it may well crash and it will be "totaled"), couldn't they have just bought a $900 drone online and attach a GoPro to it??
    A drone with a cheap camera is essentially what it is – Ingenuity isn't really doing heavy lifting on the science. It just turns out that costs millions of dollars on Mars. If it works, we'll think about whether a helicopter-focused mission with more instruments on the flying vehicle makes sense in the future. Exciting times!

  20. #240
    Quote Originally Posted by Wander View Post
    A drone with a cheap camera is essentially what it is – Ingenuity isn't really doing heavy lifting on the science. It just turns out that costs millions of dollars on Mars. If it works, we'll think about whether a helicopter-focused mission with more instruments on the flying vehicle makes sense in the future. Exciting times!
    Yea, I was just being facetious...but it DOES seem like a lot of money for a "drone" with a cheap camera attached to it. Sort of like the $10,000 toilet seats that the Air Force had bought for some of its planes.

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