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    Default Perseids The "New" Way



    Taken from here. Has anyone indulged? If so I'd love some tips! I don't particularly enjoy the moon, but I could sit outside and do this. If anyone else is interested, perhaps here would be a good spot to partner up.

    Quote Originally Posted by nasa.gov
    There's more than one way to watch a meteor shower.

    One, the old-fashioned way: Find a dark place with starry skies and count the meteors streaking overhead. Two, the new way: Find a dark place with starry skies and then completely ignore the meteors. Instead, watch the Moon. That's where the explosions are.

    On August 9th, a pair of amateur astronomers on opposite sides of the United States did it the new way. With the Perseid meteor shower just underway, they fixed their cameras on the Moon and watched meteoroids slam into the lunar surface. Silent explosions equivalent to ~100 lbs of TNT produced flashes of light visible a quarter of a million miles away on Earth. It was a good night for "lunar Perseids."

    "I love watching meteor showers this way," says George Varros, who recorded this impact from his home in Mt. Airy, Maryland:

    The flash, which lit up a nighttime patch of Mare Nubium (the Sea of Clouds), was a bit dimmer than 7th magnitude--"an easy target for my 8-inch telescope and low-light digital video camera."

    Hours later, another Perseid struck, on the western shore of Oceanus Procellarum (the Ocean of Storms). This time it was Robert Spellman of Azusa, California, who caught the flash. "It's exciting to witness these explosions in real time," he says. "I used a 10-inch telescope and an off-the-shelf Supercircuits video camera."

    Rob Suggs of NASA's Meteoroid Environment Office has reviewed the data. "They look real to me," he says. "The flashes appear in multiple video frames and the light curves are similar to other lunar meteors we've recorded in the past."

    Suggs would know. Along with colleague Bill Cooke, he leads a team at the Marshall Space Flight Center that has recorded more than 100 lunar explosions since 2005. "We monitor lunar meteors in support of NASA's return to the Moon," Suggs says. "The Moon has no atmosphere to protect the surface, so meteoroids crash right into the ground. Our program aims to measure how often that happens and answer the question, what are the risks to astronauts?"

    see caption

    Above: A map of 100 lunar meteors observed by astronomers at the Marshall Space Flight Center since 2005. Every impact on the map was bright enough to see with an amateur telescope. [more]

    NASA's official lunar meteor observatories are located in Alabama and Georgia. Both were off-line on August 9th, so the NASA team didn't see how many Perseids were hitting the Moon that night.

    "This shows how amateur astronomers can contribute to our research," points out Suggs. "We can't observe the Moon 24-7 from our corner of the USA. Clouds, sunlight, the phase of the Moon—all these factors limit our opportunities. A global network of amateur astronomers monitoring the Moon could, however, approach full coverage."


    Sign up for EXPRESS SCIENCE NEWS delivery
    By day, George Varros is a software engineer at NASA headquarters. After work, he takes off his NASA badge, goes home and fires up his self-described "barely adequate" telescope. "Until a few years ago, I really didn't like the Moon because it interfered with my observations of comets and meteors. Then, in 1999 during the Leonid meteor storm, (fellow amateur astronomer) David Dunham photographed six lunar impact events from my backyard in Maryland," Varros recalls. "I was hooked."

    Dunham's observations inspired not only Varros, but also NASA. "Our own observing program can be traced back to those early amateur observations of lunar Leonids," says Suggs.

    A major advance in lunar meteor detection came in 2006 in the form of LunarScan, a computer program written by amateur astronomer Pete Gural that searches digital video of the Moon for split-second flashes. Using LunarScan, Varros has bagged at least a dozen lunar meteors. Three of them were observed simultaneously by the NASA team in Alabama, confirming the fidelity of Varros' techniques. (LunarScan may be freely downloaded from Varros' web site; NASA uses the program, too!)

    see captionRight: Spellman's lunar Perseid, recorded from his home near Los Angeles at 0406 UT on Aug. 9, 2008. [more]

    Like Varros, Robert Spellman's interest in lunar meteors began with the Leonids of 1999. "I read about the success of amateurs recording impact flashes," he recalls. "I've been in love with the Moon since my first observation when I was five years old, and I wanted to conduct an observing program with scientific value. Lunar meteors were a natural."

    Spellman's day job is at the Natural History Museum of Los Angeles and the La Brea tar pits where he works as an educator. He also conducts public astronomy programs three nights a week at the Griffith Observatory. The rest of his evenings he devotes to the Moon.

    Spellman uses no special software to catch his impacts. "I look for the flashes in real time," he says. "Although it may sound tedious to stare at a blank screen for hours on end, the prospect of seeing an explosion keeps me alert. In future, I do plan to use LunarScan to increase my success rate."

    Suggs hopes other amateurs will take up this hobby, not only to improve NASA's lunar impact statistics, but also to support the agency's LCROSS mission: In 2009, the Lunar CRater Observation and Sensing Satellite (LCROSS) will intentionally dive into the Moon, producing a flash akin to a natural lunar meteor. Unlike natural meteoroids, which hit the Moon in random locations, LCROSS will carefully target a polar crater containing suspected deposits of frozen water. If all goes as planned, the impact will launch debris high above the lunar surface where astronomers can search the ejecta for signs of H2O. The impact flash (if not hidden by crater walls) and the debris plume may be visible to backyard telescopes on Earth: details.

    Ready for meteor watching--the new way? NASA offers a FAQ and telescope tips to help you get started. Good hunting!

  2. The Following 2 Users Say Thank You to jeebusroxors For This Useful Post:

    MarkM (07-09-2009),RussL (07-12-2009)

  3. #2
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    That sounds cool, never heard of that. I wonder what sort of magnification you would need? I know with my scope, if it was more than about 120x or so, I wouldn't be able to get the whole moon in my FOV. Much higher than that it would be just by coincidence if I saw anything. That's certainly intersting though.
    I'm just the opposite of you in one respect. I LOVE observing the moon. The one object in which I can see serious detail!

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    I'm not sure. I'd love to find out more info on how to do this.

    Don't get me wrong, I enjoy looking at the moon, but I eventualy get bored and go hunt for some new stuff. I guess things would be different if I were to try and identify ridges and craters and what not. I do want to check out the Apollo sites though!

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    More info:

    1) What kind of telescope and camera do I need?
    The “Minimum System Requirements” document describes what we believe to be the minimum
    hardware required to provide useful data. It also describes the system we use at NASA’s
    Marshall Space Flight Center. In general, you need a big enough aperture to collect the light
    from the relatively faint flashes and you want a large enough field of view to see a significant
    portion of the dark part of the moon. The more surface you can see the more impacts you will
    see. This drives you to a relatively “fast” optical system with short effective focal length. This
    can be accomplished using a focal reducer if your telescope is f/8 or greater. Our initial work
    was with a 10 inch f/4.7 and we are now using two 14 inch f/8 telescopes with 0.33
    magnification focal reducers and a 20 inch f/8.1 with a focal reducer adjusted to 0.25
    magnification to give the same field of view as the 14 inch telescopes. A sensitive black and
    white video camera is essential. Camcorders and webcams are not sensitive enough, but
    “astronomical” video cameras have the required sensitivity. A video frame rate is vital in order
    to detect the short flashes. Integration with a CCD camera will not work. Full exposure at frame
    rates of 30 per second (NTSC) or 25 per second (PAL) is necessary. The exposure time should
    equal the frame rate. In other words, there should be no dead time between exposures since a
    flash can appear at any time.
    2) When should I make my observations?
    Observations should be made when the moon is between about 10% and 50% illuminated on any
    clear night. This is a crescent phase to quarter phase. This includes both the waxing (evening
    observations) and waning (morning observations) phases. Between quarter and full phases the
    sunlit portion of the moon is too large and its glare reduces visibility of impact flashes. Phases
    less than 10% illuminated are so close to the sun that the moon sets too soon after sunset or rises
    too close to sunrise to provide much useful data. Also, the elevation of the moon is so low that
    atmospheric extinction reduces the detection of faint flashes. Meteor showers occurring when
    the viewing geometry is correct give a greater probability of seeing an impact, but we are
    interested in the sporadic background meteors. See FAQ #6 below for more information.
    The minimum scope was listed at 8" with ~1m "effective focal length". Is that any different than the 1200 listed on my scope?

    I don't have a video camera, much less a mount, and I've only got a dobsonian. May be a bit difficult for me.

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    The 1,200 on your telescope is its focal length expressed in millimeters which is the same as 1.2 meters (m).

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    Yes, I have never heard "Effective" focal length. Is this a way to differentiate from the length and ratio?

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    Jeeb, their info is confusing. And no, I haven't heard of "effective focal length" either. I have heard of "effective aperture" where aperture is sometimes cut off some by a baffle or other intrusion. The way it is worded makes me feel like "effective aperture" is synonymous with "focal ratio" in the author's mind. At first--then, it makes me think they are referring to the change in focal length that occurs after installing a reducer. I think the latter is the correct assumption. As Ted said, your scope is at 1200mm focal length. I think that's all there is to it, could be wrong, though, I'm no expert.

    Now, all the talk about focal reducers was confusing, too. Where they say "0.25 magnification" comes into my mind as meaning either a 25% reduction in focal length or 25% of what it was to start with. Or the same principles could apply to focal ratio instead. I have no idea which is true, if any. If I had to bet, I'd choose 25% less focal ratio. Again, might be wrong. I say that because the reducers I see for my SCT are stated to take it from say, f10 to f6.3 (there are different ones to choose from). That's not a 25% reduction, but certainly not 25% of the original number either. Just a guess on my part.

    I'm following what they're saying about field of view. That with the reducer talk makes me think they're talking about lower powers. Now, I don't mean like what I get on my refractors with 400 and 600mm focal lengths. It's just that if you can see the moon at 300x, or whatever, if you can also get a wide true field of view you'll be better off. To get some power and a wide view a larger telescope does best since it will have a longer focal length to produce that power, moreso than a smaller one at the same focal ratio. (In other words it's at a larger scale in all respects).

    This is an interesting topic.

    Hm, let's see, you've expressed interest in LCROSS, now more explosions on the moon during the Perseids---- you shoulda been with me at the Peach festival where the moon was right in the middle of the fireworks.
    Last edited by RussL; 07-13-2009 at 12:10 AM.

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    Yes, quite confusing! I figure I'll give it a shot, won't hurt anything. Now I just need to invent a remote EP I can wear while sitting back in my chair!

    Quote Originally Posted by RussL View Post
    Hm, let's see, you've expressed interest in LCROSS, now more explosions on the moon during the Perseids
    Oh...you know how us jarheads get with explosions
    Space is big.

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    Quote Originally Posted by jeebusroxors View Post
    Yes, quite confusing! I figure I'll give it a shot, won't hurt anything. Now I just need to invent a remote EP I can wear while sitting back in my chair!



    Oh...you know how us jarheads get with explosions
    LOL, now there's an idea! With bino vision.

    And since you live near Ft. Jackson, you might could catch a few tracers out on the range at night. Or firecracker round? Ahh, the smell of powder.

    BTW, I'm not sure how you add a reducer to a Newtonian, other than by using a long focal length eyepiece. But that would just give you low power. Hopefully someone will chime in that knows more than I do.

    Aren't we having some nice clouds?

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    Yea, I'm not too sure either. I think they're just saying to watch as much of the dark side as possible. I'll probably just end up using my 6mm...but in reality I'll watch for a few minutes, then become bored. Maybe if I didn't have these damn neighbors I could throw on my Dark Side album for inspiration.

    Yes, these clouds are great. Tonight looked ok, although I was over at a pub on Rosewood for the All Star game, and saw about 4 stars. That was probably due to light pollution though.

    Oh and by the way, you have won. I've been contemplating a 2inch EP, maybe 32mm 60 degrees or so. I've seen a few "decent" ones for around 100, but I think I'd like to check it out first. I say this now, but we'll see how itchy my buying finger gets.

    There's also a Celestron Omni XLT 102 for 200 bucks on craigslist I've been contemplating. May be a good, cheap way to break into photography (of the stars, not my neighbors).
    Space is big.

 

 

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