[meteorite-list] Leonids (was Holmes Swallows...)

From: mexicodoug <mexicodoug_at_meteoritecentral.com>
Date: Tue, 20 Nov 2007 19:31:41 -0600
Message-ID: <006201c82bde$45c0daa0$4001a8c0_at_MICASA>

"last look at Holmes, look up in its direction and whisper, "Encore!
Encore!" "

Hi Sterling,

Yes, an encore would be nice! I'm waving a lit cigarette lighter (or is it
a cell phone screen nowadays for concert go-ers today)!

Also, did I mention that your quoting of Dylan Thomas was quite moving,
though II see his works with infinite longing and magnetism, instead of
through his bottles of liquor, like you... As you say it is a big universe
out there... (even though, sometimes in [my own] ignorance, it doesn't seem
quite big enough).

Really sorry to hear about the clouds in your skies, and thanks for being
kind in your comments on my Leonid post which I hope may have been something
of a consolation. It is expensive and difficult to make those trips so far
away from light contamination, and clear skies unfortunately are anything
but a given. Speaking of my own ignorance, let me get defensive saying I
was tired when I was writing that post, and made these three errors which
you kindly did not draw to the list's attention in the spirit of lively
discussion, though I think I should correct them here, whether we are
catching up one rainy day at the Gloucester Coffee House, or preparing a
manuscript for inclusion in Nature...

(1) I mentioned Comet SWIFT-Tuttle was the parent body of the Leonids, that
comet is the parent of the Perseids. Leonids are TEMPEL-Tuttle. Strike 1.
(2) I mentioned the leading edge of the coma being rounded and the
"trailing" edge of the "coma" (Mirphak side) irregular and vaporously and
wispily disappearing. I think I got that backwards, but I'm still to tired
to check. It was a morning observation closer to comet set, and my other
observations were evening close to comet rises. Strike 2.
(3) I used the word "fireball" liberally, when in fact, only four meteors
were bona-fide fireballs, according to AMS convention: near equal or
greater than Venus' brightness. And sometime way back, I believe Chris and
maybe even I also mentioned that the arbitrary definition of "fireball"
needs to be yea big. In my defense on this one, with a sky in which I could
see better than +6.8 magnitude things with normal glasses, a brilliant -1
magnitude meteor was brighter than the way I see Venus normally. The eye,
once dark adapted, doesn't really relate to "absolute" magnitudes, but
rather relative magnitudes. Can you imagine Venus washing out half of the
sky and causing the casting of shadows - that was the situation. So while I
have been very unscientific in that sense, if you had seen them, especially
with the frequent splitting at the ends of visible flight like sparklers
(Bengala lights), you might be tempted call that comment safe and let it
slide. Ball 1.

Best wishes and Great health,

----- Original Message -----
From: "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
To: "mexicodoug" <mexicodoug at aol.com>; "dmouat" <dmouat at dri.edu>
Cc: <meteorite-list at meteoritecentral.com>
Sent: Monday, November 19, 2007 7:39 PM
Subject: Re: [meteorite-list] Leonids (was Holmes Swallows...)

> Hi, Doug,
> Great description of the Leonids... As always, I saw
> clouds.
>> See it over the next couple of days... if you can.
>> In another week it won't be visible
> Holmes was very dim tonight despite a clear-ish sky.
> During its "discovery" outburst (which was the only
> outburst until this year's spectacular), Holmes faded
> away, then 60 days later blazed out again as brightly
> as at first, so after your last look at Holmes, look up
> in its direction and whisper, "Encore! Encore!"
> Sterling K. Webb
> --------------------------------------------------------------
> ----- Original Message -----
> From: "mexicodoug" <mexicodoug at aol.com>
> To: "dmouat" <dmouat at dri.edu>
> Cc: <meteorite-list at meteoritecentral.com>
> Sent: Monday, November 19, 2007 7:07 PM
> Subject: [meteorite-list] Leonids (was Holmes Swallows...)
> Dear Listees,
> Three weeks ago I posted our observational results for the viewing of
> Comet
> Holmes (currently the largest member of the Solar System), and the Leonids
> meteor shower peak November 17/18 gave motivation to hike back to the same
> site and view the comet with the same binoculars: A 25X100mm astronomy
> pair
> and a16X50mm pair typical of Walmart bought for US $60.
> So, let me make a few comments of potential interest to meteorite people
> on
> what we saw in the Leonids, and then give a few impressions of the comet
> and
> how much longer this will be spectacular for most observers.
> Leonids: The night began with a half-Moon, but one wouldn't have known,
> as
> upon arrival the entire region was blanketed with various degrees from
> disasterous to unthinkable swarths of angry clouds. Every minute, the
> desert and sky would become brilliantly illuminated by multiple meteoric
> flashes - however, they were "just" amazing lightening bolts that cast all
> kinds of eerie shadows and blinded ones night vision in the pitch
> darkness.
> Hurredly we went to sleep in the tent within the tent, a construction for
> just such ocassions requiring waterproofing. Set the alarm for 4:00AM and
> said our prayers amid lamentations.
> At 4:00am, I couldn't see anything outside the windows, but luckily I
> remembered their was a tent covering the windows. Morbidly I lifted the
> outer flap covering the windows. *pinch* The sky was a 7th magnitude
> limiting magnitude at this high altitude, clear and enough to make any
> astronomer's heart sing. As if to re-enforce the shell-shock as I emerged
> from our bunker, right through the Moonless sky, a slow, sporadic,
> fireball
> painted it way across the sky, crossing of all places, Leo! It was about
> 0
> magnitude and enough to leave a persisting smoke trail momentarily as it
> went from what felt like brilliant star-lit horizon to perfectly
> transparent
> horizon. Great!!! Venus was just rising, sitting on top of a distant
> mountaintop.
> The Leonid show is always a great show as frequently bright fireballs can
> be
> seen, though typically the rate is not one of the absolute best. Under
> optimal circumstances this year was to be 10-25 meteors per hour with an
> overhead radiant. Well! the radiant over half way to the zenith and
> rising
> inside Leo's mane placed not far from a golden and respectful Saturn. We
> saw approximately 25 meteors during two hours, which actually slightly
> beat
> the odds., but let me explain first the beauty of this meteor shower for
> meteorite collectors, before I explain why.
> Of the 25 meteors observed, about half were as bright as planets, which is
> very exciting. These fireballs enter at extremely fast speeds (no more
> smoke trails or long-lasted meteors, unfortunately, but...) four of the
> meteors were fireballs that split much like fireworks, near their visual
> endpoints. Not only did these split, but they were different colors. The
> brightest of all was green (at least initially, as this can be hard to
> keep
> track of when you are taking a photo and your observing partner screams to
> look at the incredible green one). My head was down in a canister of film
> [yes, I still use film] when that one passed overhead, but no scream was
> necessary. This is because the fireball noticeably lit up the entire
> desert
> in one of those spine-tingling flash events you think, BOLIDE! METEORITES!
> SONIC BOOM???!! No, there was no sonic boom, but my head did snap up so
> fast to the instant of the end of the lighted path and fragmentation - a
> sight to behold. That is about as close as I've ever come to other lucky
> observers see when a real meteorite-dropper across their their skies...and
> hopefully into their back yard. This bolide was somewhat brighter than
> Venus, conservatively, so I am thinking it was probably initially atound
> the
> one gram range. One problem with hoping for meteorites from Leonids,
> besides their need for speed, is that they are thought to be composed of
> extremely friable material (the residue from Comet Swift-Tuttle).
> The other extremely bright fragmentors during the luminescent path were
> reddish and bluish-white colors, and the colors were so brilliant!
> Virtually every Leonid that darted through the sky seemed like a big one.
> I
> mentioned that our we saw 25 meteors in two hours, but that that was on
> the
> hight side of optimal expectations. This is because, shortly after Venus
> climbed in the Eastern sky, we found the interference the planet caused
> unacceptable while our Western half-sky was wonderful. We positioned our
> Vehicle between us and Venus, so this interference was minimized and
> looked
> basically from Leo westwards. So we only had half of the 25 per hour
> rate,
> having seen 25 amazing meteors in a magical two hour period while ignoring
> the part of the sky Venus muddied out.
> There came a time that the Sun overtook Venus a little after 6:00am, but
> we
> couldn't resist in the now quite cold and somewhat windy desert the famous
> "OK, we'll both see one more good one" starstruck syndrome...and there was
> one rather good one right through the horns of Taurus when ub that
> constellation, only the brightest star, a red giant, ALDEBARAN (15th
> brightest in the entire sky over the year) was still visible. That must
> have been quite a bright fireball!
> Comet Holmes: Just a few comments for an apple to apple comparison three
> weeks ago, through the eyes of my junior observing partner.
> Three weeks ago: It looks like a perfectly formed circular scoop of
> almond
> colored ice-cream with strong demarcation against the black background...
> Leonid night out:: the bright star [Mirphak] is inside the comet on the
> [trailing] side which finely fades like a torn cotton candy into the star
> and then the darkness. The front end looks like like a cloud that is
> still
> rounded, but everything is disappearing like vapors merging into the air
> from a chimney. No color apparent other than a blurry-cloudy white
> mixture...
> Comet Forecast: On November 18, by naked eye in a dark sky, Mirphak looked
> a
> little blurry, especially to one side. Sharper eyes easily could separate
> the comet, but it has lost most of its visible impact. That's it for the
> dramatic show. See it over the next couple of days a couple of hours
> before
> sunrise at mid latitudes, if you can. In another week it won't be visible
> except in nice dark sky locations, unless of course, there is a new
> "erruption"...this in consideration that the Moon will be starting to
> interfere by then, too...farewell, for now, Holmes, and thanks for your
> spectacular performance...
> Good Health and Best Wishes,
> Doug
> ----- Original Message -----
> From: "dmouat" <dmouat at dri.edu>
> To: "Jerry" <grf2 at verizon.net>
> Cc: <meteorite-list at meteoritecentral.com>
> Sent: Monday, November 19, 2007 3:30 PM
> Subject: Re: [meteorite-list] Fw: Comet Holmes Swallows a Star
>> Dear Listees
>> I checked out Comet "Bob" Holmes last night from the very clear skies of
>> Truckee, California (1,800m; 6,000') with a decent pair of binocs.
>> Mirfak
>> was touching the east side of the comet. A very impressive
>> (spectacular??) sight and you don't need a telescope.
>> Dave
>> Jerry wrote:
>>> check this out. unfortunately for me it's clouded over tonight
>>> Jerry Flaherty
>>> ----- Original Message ----- From:
>>> <Space.Weather.Alert.Service at spaceweatherphone.com>
>>> To: <grf2 at verizon.net>
>>> Sent: Monday, November 19, 2007 4:10 PM
>>> Subject: Comet Holmes Swallows a Star
>>>> Hi, This is Dr. Tony Phillips calling with an alert about Comet Holmes.
>>>> It's Monday, Nov. 19th.
>>>> This a message for people with backyard telescopes. Tonight, Comet
>>>> 17P/Holmes will swallow a star! Not really, but the comet will pass
>>>> directly in front of the star--named Mirfak, the brightest star of the
>>>> constellation Perseus. The overall effect will be that of a giant
>>>> cosmic
>>>> jellyfish swallowing a phosphorescent treat. You can see it happen
>>>> through even a small backyard telescope. The stellar "meal" will
>>>> continue for the next few nights, so if you miss it tonight, try again
>>>> tomorrow.
>>>> SKY MAP:
>>>> http://spaceweather.com/images2007/15nov07/skymap_north_holmes.gif
>>>> PHOTO GALLERY: http://spaceweather.com/comets/gallery_holmes_page18.htm
Received on Tue 20 Nov 2007 08:31:41 PM PST

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