Moon Rise

Discussion in 'Science / Nature' started by Moonbat, Mar 31, 2012.

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    Moonbat

    Moonbat Luna tick

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    Hi,

    Is there such a thing as a Moon rise?
    It has occured to me that although there are apps (for smart phones) out there that can tell you which phase the moon is in for any given day, they din't tell you if you'll be able to see that moon at a specific time of night.

    Am I right in thinking that sometimes the moon will not show in the sky where I live (ignoring cloud cover) until possibly 4:00am, or sometimes it'll be out in the late afternoon?

    If I'm right, I'm assuming that there will be a way to calculate when the moon will be in the sky for any given location on earth?
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    Abernovo

    Abernovo Accident-prone, allegedly

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    I use Google's Chrome browser (works better with my slow connection), which has a Planetarium app on it showing the position of the stars, Moon and planets at any given time. It's adjustable to location, as well.

    Just had a quick look at it. It's an app from neave.com. Maybe they'll have something on their site. I've never visited it myself.
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    HareBrain

    HareBrain Lagomorphing Staff Member

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    Basically, full moon rises at sunset, anywhere in the world. Then it's about an hour later each day. New moon rises at sunrise. A waxing, half-full moon will be high in the sky at sunset, and a waning, half-full moon will be high in the sky at dawn.

    (If you think about why the moon is full, or new, it should be obvious why it has this relationship with sunrise and sunset.)

    I know this isn't GWD, but it amazes me how many published novels have the new moon rising in the evening.
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    The Judge

    The Judge Truth. Order. Moderation. Staff Member

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    Dave

    Dave Wherever I Am, I'm There Staff Member

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    Basically, that is correct. I don't know why exactly, but it is slightly more complicated than that. Your latitude is very important and even the small difference between, say Portsmouth and Inverness, makes a huge difference to the precise time of rising or setting. Also, your altitude makes a big difference since your horizon is more distant.

    The dates of Islamic holidays are determined by the Islamic lunar calendar and so are very important to Muslims. These are only estimated based upon the visibility of the hilal (waxing crescent moon following a new moon). I would expect that if it was so easy to calculate moon rise, then the dates would all be known in advance, but each year they only make estimates based upon the expected visibility and this also varies widely according to location.

    I'm interested if someone knows why the dates cannot be calculated precisely in advance.
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    Dave

    Dave Wherever I Am, I'm There Staff Member

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    HareBrain

    HareBrain Lagomorphing Staff Member

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    That's also true of sunrise and sunset, of course. It might well be more complex than I suggested, but I've always found it helpful to think of the full moon as being in opposition to the sun -- so the full moon is high in winter and low in summer (the sun high in summer and low in winter); the full moon rises as the sun sets, etc. Observation suggests it seems to work. The scientific explanation is probably something to do with a falling-out they had in ancient times.
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    hopewrites

    hopewrites Happily Ever Aftering

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    Oftentimes I see the moon out late in the evening. are you saying rise as in its ascension into visible skyskape, or rise as in oh look now its dark enough to see that the moon is out?
    one winter evening I saw the moon out around 2 in the afternoon. my mom didnt believe me (i was a very small girl) and had to be pulled outside to see. she was adequately impressed before she went back to the dishes and I went back to building an empire out of sticks in the mud.
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    Starbeast

    Starbeast Benevolent Galaxy Being

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    I love seeing a big, bright full moon on the horizon. Once in a while I'll whip-out my little telescope and study the spectacular cratered landscape.

    The moon will be full again on April 6th. ;)
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    Metryq

    Metryq Cave Painter

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    Stellarium is a free, open source stellarium for your computer (multi-platform). I've played with many similar apps—for desktop computers, smartphones, etc.—and they're all more or less "accurate" for current events. I cannot comment on exactly how accurate Stellarium is.

    I recall using an app called Digital Universe, made by Syzygy, and the makers used to blow their horn about how accurate it was, even over extremely long periods of time. I think it may have had compensation for different calendars, too, but I'd have to dig out the documentation. I left the app behind when it was not updated for changes in the Mac OS. I cannot seem to find the company site right now; the last time I checked it, the app was available only for Amiga OS...

    Anyway, there are many alternatives to choose from. If all you want is just the times for events (sunrise/sunset, moonrise/moonset and moon phase, etc.), you will also find many computer calendars and clocks with such features. Check http://download.cnet.com or any other software search site.
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    Moonbat

    Moonbat Luna tick

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    Thanks for the replies everyone, I have found that my google nightsky app has the moon on it, but I want to be able to check if the moon will be full on a certain date in the future, or find the dates when it will around a certain time in the future (and not too far, we're talking a year or two not centuries).

    Good point Hopewrites, I guess I mean both, this afternoon the moon was out early, from what HB said I guess that means that it is presently waxing (that means getting smaller? it was over a half moon) but I do mean when will it be rising as in ascension into visible skyscape, and then I guess the brightness will be when it is visible.
  12.  
    Metryq

    Metryq Cave Painter

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    Most planetarium/stellarium apps automatically set themselves to the current computer time, although you can open the clock control panel (of the astronomy app) and set it for any time you like. Most apps will then show the phase of the moon, as well as its position in the sky.

    The phases of the moon (at least in the northern hemisphere) are the reverse of readwise—that is, the light starts on the right )

    waxes up to full 0

    then wanes down to the left. (

    Perhaps you've seen the following animation:
    http://www.youtube.com/watch?v=woTCsNNfYEE

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    HareBrain

    HareBrain Lagomorphing Staff Member

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    You get one more guess. :)

    It will be full this Friday.
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    Karn Maeshalanadae

    Karn Maeshalanadae Why?

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    Actually, Moonbat, waxing means it's getting fuller, waning is when it is getting newer.

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