Light years?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by wegs, Jul 16, 2022.

  1. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

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    Not sure which logic you're using to make sense of it? Some form of binary approach (1, 2, 4, 8 etc?).
    Trillion used to be 10^18, because the n-illion in the long-scale of numbering refers to million-to-power-of-n. So Trillion is Million^3. Quadrillion is Million^4 etc. That's not only the correct logic but surely also the more sensible.

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    Then come those pesky Americans and ruin a good thing! Typical!

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    There are a handful of galaxies that you might be able to observe with the naked eye. If you knew where to look. And what to look for. And don't mistake it for just another blurred light in the sky.

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    Andromeda, our closest spiral galaxy, is one such. The Megellanic Clouds are another.
    You wouldn't be able to discern stars within those galaxies, though, so if you know you're looking at a star it is one within the Milky Way.
     
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  3. DaveC426913 Valued Senior Member

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    And have the eyes of a young pup.

    Not for want of trying, but I have never been able to make out Andromeda, even in the dark skies of the Caribbean.
     
    Last edited: Jul 20, 2022
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  5. Seattle Valued Senior Member

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    Really? When it's late enough and Andromedia is overhead (late summer) I can make it out even in Seattle (light polluted). It's easier of course with binoculars (which is better and easier than using my telescope).
     
    Last edited: Jul 20, 2022
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  7. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

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    You mean Billion meaning million^2, trillion meaning million^3 etc? Ever since the long scale was devised, I guess. I've taken some liberty in the wording, but the original idea was that "billion" was a thousand thousand million, and a "trillion" was a thousand thousand billion, and that amounts to the pre-fix referring to powers of million. I think this goes back to late 15th century or so.
    Me either, only ever with a telescope. But then I wouldn't really know what or where to look at.

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  8. DaveC426913 Valued Senior Member

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    Yeah. I looked that up and retracted my question (too late).

    I took great pains to memorize the spot but no joy.

    I think I never got a clear idea as to how large to expect it to be. It depends on what source you use - it's either a small smudge or a huge smudge, bigger than the Moon. It's so faint that you really got to know what to expect to be able to see such a fuzzy object.
     
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  9. Seattle Valued Senior Member

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    The easiest way to find Andromedia is to wait until it's directly overhead when facing South at about midnight (which is late summer/early fall as I recall). You locate the Constellation Pegasus first and follow the upper "line" connect two bright stars and then you can orient yourself toward Andromedia (just look at a Constellation chart to get the general orientation).

    It will just look like a dim, blurry, small "cloud". Use binoculars and it will because a little more obvious. It won't look like the photographs of the Andromeda Galaxy but it will be distinct from the surrounding area. With a small telescope it will take on a little more form but it will still just be a milky blur.

    Dave is correct in that you have to know what to expect. If you find it once it will be much easier to find again since you will then know what to expect. If it isn't the right time of year and time of the night when it is overhead you aren't going to see it anyway.

    If you want to see a nebula with the naked eye and much better if you have binoculars wait until December when Orion is high in the sky in the South at 11 pm or so and locate the Constellation Orion (easy to find as it's very large) and look at the area that is supposed to represent Orion's belt and you can easily see the Orion nebula.

    The 3rd object that I can think of that is nebula like and viewable with the naked eye and even better with binoculars is the Pleiades (7 sisters and where the Subaru logo comes from). This is viewable late night/early morning in late fall (I think).

    You can look at a star chart/Constellation chart for general reference at to location/time of year/time of night and it's pretty interesting.
     
    Last edited: Jul 20, 2022
  10. DaveC426913 Valued Senior Member

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    Yep. I know exactly where to look, and am comfortable with "star-hopping". I just can't make anything out.
    Of course, I didn't start looking until my eyes were well over 40 years old.
     
  11. Seattle Valued Senior Member

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    8,874
    I'm older than you. There are a lot of factors, light pollution, and knowing what to expect and what not to expect. It isn't lit up like the Moon

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    so it stands out only when there is little light pollution but even in Seattle, late enough at night, looking in the right spot you should be able to see it. It is straight up as well so it's hard on the neck (a reclining lawn chair helps).

    If you have access to binoculars that helps as well but again it's a matter of light gathering so if they are inexpensive "terrestrial" binoculars they may not help. I can see it with the naked eye but I also have some binoculars made just for star viewing (larger aperture) and that is helpful as well.

    I found the Ring Nebula once with a larger telescope. Even though the Ring Nebula is fairly large it is faint as well so easy to overlook. That telescope is no longer working and I just have a smaller telescope and I can't find it (Ring Nebula) anymore even though I know where it is.

    It's easy to see planets since they reflect the sunlight. Nebulas are harder to see and the Andromeda Galaxy looks similar to a nebula.

    I guarantee that if you have an area of your yard where you can at least block some street light pollution that if I were there I could point it out to you at the right time/location and you would see it and after you saw it once you would be able to find it on your own after that.

    It's just one of those things where it might be hard to find and see when you don't quite know what you are supposed to be looking for. They describe it as being as large as the Moon but the Moon is very distinct and well lit. The Andromeda Galaxy isn't bright, is a milky blur and that blur may cover as much area as the Moon but it isn't distinct like the Moon.

    I rarely look at it since it can't be a cloudy night, it has to be straight up in the South and I have trees on either side of me so it needs to be summer and about 1 pm for me to even see it. I'm usually in bed by then.
     
    Last edited: Jul 20, 2022
  12. DaveC426913 Valued Senior Member

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    18,959
    This is one of the things that's confounded me. Technically, M31 subtends an area 3x as wide and 2x as high as the Moon, and some astro guides illustrate this.
    Others show it more realistically as only what can be perceived by good eyes - which is nearer the size of the Moon.
    Even poorer eyes might make out only the brightest part of the central bulge.

    Compounding that with sky conditions means what "what to expect" is very subjective - much more so than other celestial objects.

    When I've observed I've tried to set my attention on the whole range of expected sizes, but still no joy. I agree that, if I were able to spot it once, I would know what to expect thereafter.
    Unfortunately, my eyes will never be better than they are - or were a decade or two ago - so that ship has sailed for me.

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  13. Seattle Valued Senior Member

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    M31 is frustrating to me too. That's a matter of light pollution for me. You locate Hercules and it's a "box" but these days in Seattle even Hercules is hard to pick out due to light pollution. Once you find it M31 is on the right vertical side closer to the top than to the bottom.

    I used to be able to find it pretty easily but now there is just too much light pollution. To see M31 I would need to use my telescope or my binoculars but it's much harder to pick out these days. When you do see it, like much of astronomy, you see it by not looking at it.

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    You use the rods rather than the cones so an indirect gaze is what works. That's annoying of course.

    If you have binoculars and you are frustrated with not being able to find/see M31 or Andromeda try the Pleiades and the Orion Nebula. You will see those with binoculars without having to gaze indirectly or wonder whether you are seeing it or not.

    Even astronomy is frustrating and is a matter of managing expectations. It becomes more interesting when you combine what (little) you can see with what you have learned from reading. You can look at a star and it's boring unless its a different color or a binary star but if you've read about the life cycle of stars, how they are formed, or something unique about that particular star then it's interesting.

    If you haven't done the research and are just looking at that dot of a star it's not too interesting. If you know how many planets are around it, how fast it's spinning, how large it is or how far away combined with locating it, it's a little more interesting.

    Jupiter and Saturn are the no-brainer objects for any small telescope. Jupiter more so because of the 4 major moons that change position enough to notice, on a hourly basis. Saturn is impressive just because of how "alien" it looks even though it's very small though an amateur telescope but it is distinctive. Most people feel some sense of awe the first time they see it though a small telescope.
     
  14. wegs Matter and Pixie Dust Valued Senior Member

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    I purchased a telescope a few years ago and it was on the cheaper side, but unfortunately it broke in under a month. It wouldn’t “stand” properly as when I first bought it (don’t even recall what I may have done to cause this) and a zillion instructions to put it together.

    I’m interested in deeper sky objects, but don’t want to spend too much on a new one. There’s an amateur astronomy group in my area and they meet twice per month for dinner and exchange ideas, insights, etc… it could be fun to join something like that.
     
  15. DaveC426913 Valued Senior Member

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    18,959
    That's a very good idea. Whenever anyone wants to start into astronomy observing and ask about scopes, most of us buffs will strongly suggest they join a local club. You'll learn a lot about star-gazing as well as about telescope selection.
     
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  16. DaveC426913 Valued Senior Member

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    Yeah. Naked eye objects. I've turned my 5.5-inch Newt on them a few times.


    Yep. I'm a planet guy. I like sketching Jupiter's moons and Mars' features.

    I am particularly pleased with comparing my sketches of Mars with the actual disc of Mars as seen at those times on those days via NASA's virtual telescope:

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  17. wegs Matter and Pixie Dust Valued Senior Member

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    Yes, I’m definitely curious about it. So, I just checked online and you can rent higher end telescopes by the day/week to test them out to see which one might be best.

    There’s also this:

    https://www.gearbrain.com/review-skyview-stargazing-app-2439280572.html

    It looks like it’s more of a constellation locator and identifier, but sounds kind of interesting.
     
  18. DaveC426913 Valued Senior Member

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    I did not know you could rent scopes.
     
  19. wegs Matter and Pixie Dust Valued Senior Member

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    One shop offers rates from $10-100 per day, so it could get expensive if you’re an indecisive person. lol
     
  20. Seattle Valued Senior Member

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    8,874
    Or if it's cloudy

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  21. Seattle Valued Senior Member

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    Nice Dave!
     
  22. wegs Matter and Pixie Dust Valued Senior Member

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    So true! For $100 per day, I better see a space alien.
     
  23. Seattle Valued Senior Member

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    Has anyone ever seen one through a telescope?

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