[meteorite-list] COMET McNAUGHT IS STILL VISIBLE IN DAYLIGHT!

From: MexicoDoug <MexicoDoug_at_meteoritecentral.com>
Date: Thu, 18 Jan 2007 04:24:04 -0600
Message-ID: <03e601c73aea$c979a7e0$a8c85ec8_at_0019110394>

"This brings up a question to all. Did anyone down south of the equator see
this [comet] in broad daylight from 01/12 to 01/16? All the reports I have
thus far seen are from the north. It should have been easily seen in broad
daylight down there as the sun would be higher in a blue sky."

Hello Steve,

Please correct me if I've not understood your statement but, this is not
appreciably true. Lets say you have in 2 km elevation Flagstaff a view with
the Sun at 33? high in the sky (only one third above the horizon=0? to the
zenith=90?). And lets compare that to a location down south near the tropic
of Capricorn (where the Sun is at a neckbreaking 88? altitude, basically at
the zenith). Call that place Rio's Ipanema Beach, at sea level.

Both locations have a similar loss of magnitude, just about 0.3. Actually
Flagstaff is a little better off by a few percent. So in both places, the
comet would appear to be -4.7 magnitude instead of the true e.g., -5.0, from
sitting on top of the atmosphere like Hubble. The point is, with something
this bright, the difference is much more sensitive to other things and you
have minimal loss. Even if the comet were at the exact zenith and you were
2,000 meters above Rio, you would still lose 0.2 magnitudes - after all you
can only do so well from the soup we live in and it is a light contaminated,
polluted muck once you are outside the fishbowl looking in...

The moral of this is that few people in Arizona (well, Phoenix probably
realizes the way it was) and New Mexico know just how uniquely lucky they
are. When we start to factor seeing, dust and humidity into the equation
you guys are basically on the top of the world as you have an especially
cooperative airmass on top of you. Plus, I suspect that the greater
magnitude of the Sun in a zenith situation - takes its toll on contrast with
our poor eyes as well making it at best a wash.

Btw, plenty of folks saw it in the Southern Hemisphere during the day and
twilight, though everyone had to put up with the same 5-7? angular
separation from the Sun from our little Blue Spaceship Dot, the comet being
120 million kilometers away. The tail has improved somewhat apparently.
(Thus - Arizona highlands was just about the finest place to be, all things
considered). It apparently gave the Ozies quite a show in Perth last
evening - like you northerners had. But the Northern hemisphere really got
first dibs on this comet. Did you know if you were in Barrow, Alaska you
could have watched the comet rise and set from about 9 am to 5 pm every day
for the first two weeks of January - and even had to worry about the Sun,
because it won't be rising there until say, January 23. Might be a wee bit
nippy, but I think that the coinciding of a comet rising and setting instead
of the Sun is the stuff of legends that turn men's bones into stones...And,
we're meteorite hunters (I read Gallant's book, too and am a little hyper),
the (-) 26? below zero FAHRENHEIT (-32?C) right now would be good practice
for Antarctica, or maybe even Dave's Wyoming... It got up to -14?F (-26?C)
yesterday in Barrow which was typical for the high-noon comet a few days
earlier.

Good health,
Doug
PS, you can still see the Comet's tail after Sunset from your skies - hope
you check this out. Did you know the Comet is the largest object in the
Solar System at the moment, a mere 10-20 million kilometers long and with a
tail wider than the Sun?


From: "Steve Schoner" <schoner at mybluelight.com>
To: <schoner at mybluelight.com>
Cc: <meteorite-list at meteoritecentral.com>
Sent: Wednesday, January 17, 2007 9:32 AM
Subject: Re: [meteorite-list] COMET McNAUGHT IS STILL VISIBLE IN DAYLIGHT!


Hello all,

Don't know why my report of my last daylight sighting of this comet
(01/16/07) did not go through, so I post again. I was very impressed to
have spotted it yesterday in Flagstaff's clear blue skies, and I had
some of my co-workers come out and confirm my sightings. They were
just as amazed as me to have seen it. I also pointed out Venus well to
the left and up above it which they also spotted as well. They were
amazed that I pointed it out as they had no idea that one could
actually see a planet in broad daylight.

In regards to Comet McNaught the "forward scatter" is rapidly vanishing
and it is very unlikely that it will be seen today by anyone in broad
daylight (unless you are on a very high mountain with very clear
skies). I will give it my last try this afternoon. If I can't see it
with my naked eyes, I won't try with binoculars as it is too dangerous
to look anywhere near the sun.

This brings up a question to all. Did anyone down south of the equator
see this in broad daylight from 01/12 to 01/16?

All the reports I have thus far seen are from the north. It should
have been easily seen in broad daylight down there as the sun would be
higher in a blue sky.

Steve Schoner
IMCA #4470
Received on Thu 18 Jan 2007 05:24:04 AM PST