Re: Can one see stars from a high altitude balloon or a plane ?
Martin@nezumi.demon.co.uk (Martin Tom Brown)
Sat, 25 Jan 97 10:19:07 GMT
In article <32E6F72B.482@inetnebr.com>
wa0cky@inetnebr.com "Richard P. Johnson" writes:
> John O'Reilly wrote:
> >
> >
> > Somewhere I remember reading that WW2 Japanese pilots ( a select
> > few) where somehow trained to locate stars in daylight. The book also
> > said that if you were at the bottom of a 50 foot well, that it was
> > possible to see the stars if you looked straight up since apparently a
> > lot of the scattering is reduced from that perspective. Anyone care
> > to comment?
>
> Don't know about the Japanese fighters but the well story is an old
> wives tale. No matter how deep the well you'll not see the stars with
> any more contrast against the sky than if you weren't in the well. Does
> anyone know the origin of this myth? The only thing I can think of is
> very bright starlike objects such as Venus can be seen in daylight
Since Venus is so easy once you know where to look I am inclined to
believe that the deep well story might have a grain of truth in it.
Stars like Sirius, Canopus, Acturus & Vega must be close to daytime
sky brightness levels, a little help might make them visible.
I think I read somewhere the original well experiment was attributed
to Bradley, but I cannot relocate the reference.
Regards,
--
Martin Brown __ CIS: 71651,470
Scientific Software Consultancy /^,,)__/
Re: UNCC IMAGES GONE!!!!
Daniel Vietor
Sun, 26 Jan 1997 01:04:31 -0500
Keith Ocheski wrote:
> Most of the other sites I know about (Purdue, SUNY, GRADS) are slow to > update their maps (if they update them at all)and often are missing
> data.
Let me see what I can do to answer some of these questions since the
reliabilty of my server has come into question.
First, Purdue's Internet access is not the best in the world. We have
been fighting problems with our Internet provider ANS which has caused
some of our data to not come in during daytime hours. This means data
like satellite imagery may not even update during the day. This is
beyond my control. BTW, ANS is not the only Internet provider with
problems due to the overwhelming use of the Internet.
Second, the source of data UNCC has is nearly inaccessible to us at
Purdue since transferring even the smallest of data files would be too
slow to be useful. As a result, I must rely on the standard NWS feeds
of data which is not as timely nor as reliable. Sometimes transmission
is corrupted or grids just not sent at all. The speed of transfer
prevents some data like the 12Z AVN model from getting in here before
22Z.
We get our data either via satellite feed or via the Internet which can
bog down to the point we get no data. Both feeds have their weaknesses
but we must rely on what we have available.
I hope our Internet problems get fixed so access and reliability can
improve.
Geoff Fox wrote:
> The beauty of what you did was the fine tuning of the WXP parameters.
> Would you be willing to allow someone else (most likely a college or
> university) to run WXP using your settings? There are a number of
> schools that display model outputs, but with nowhere near the visual
> impact.
Alot of sites are using WXP to make graphics for the Internet and each
site has its own twist. At last count there were over 15 universities
generating images for the net using WXP.
I would be willing to take on some of the UNCC plots. One of the
reasons I haven't added these types of plots is that I'm in the middle
of a major upgrade of WXP. I'm impressed Mike has been able to get
alot of this done without the documentation I'm still attempting to
write.
This calls into question the whole weather web site issue. Since alot
of the weather data and access to information is being privatized, there
is a question as to how long free access to plots such as the Purdue and
UNCC sites provide will continue. Private companies are willing to
fight universities over the issue of who can put these images onto the
network and whether realtime weather data is truely in the public
domain.
Second, there is the issue of what data to put out there. NCEP only
broadcasts a limited number of MRF fields to the general public and
putting the full 14 days forecasts out there might be crossing the lines
of what is acceptible to NCEP due to their strict quality control. I'm
not going to call into question some of these issues.
Third, there is the processing issue. It would be nice to put it all
out there but the processing power is out of the reach of most
institutions. This is why you need several universities to cover the
breadth of products. Of course putting all these images out for free
would really put the private weather companies at a serious
disadvantage. Back them into a corner and they will fight.
Finally, there is the cost issue. The universities are starting to take
a BIG look at the burdens of putting widely used web servers out on
their networks using their computers and personnel Without money to
fund the effort, there is little justification to continue the effort.
I will try to keep my server going and will improve it sometime in the
near future (once I get the rewrite done). Hopefully the road bumps
won't be too serious.
========================================================================
Daniel Vietor INTERNET devo@cell.atms.purdue.edu
Dept of Earth & Atmospheric Sciences TITLE Senior Project Specialist
Purdue University WXP Developer
West Lafayette IN 47907 WXP http://wxp.atms.purdue.edu
PH 317-494-3292 FAX 317-496-1210 EAS http://meteor.atms.purdue.edu
========================================================================
Re: Can one see stars from a high altitude balloon or a plane ?
mmd@zuaxp0.star.ucl.ac.uk (Michael Dworetsky)
Sun, 26 Jan 1997 12:53:02 GMT
In article <854187547snz@nezumi.demon.co.uk> Martin@nezumi.demon.co.uk writes:
>In article <32E6F72B.482@inetnebr.com>
> wa0cky@inetnebr.com "Richard P. Johnson" writes:
>
>> John O'Reilly wrote:
>> >
>> >
>> > Somewhere I remember reading that WW2 Japanese pilots ( a select
>> > few) where somehow trained to locate stars in daylight. The book also
>> > said that if you were at the bottom of a 50 foot well, that it was
>> > possible to see the stars if you looked straight up since apparently a
>> > lot of the scattering is reduced from that perspective. Anyone care
>> > to comment?
>>
>> Don't know about the Japanese fighters but the well story is an old
>> wives tale. No matter how deep the well you'll not see the stars with
>> any more contrast against the sky than if you weren't in the well. Does
>> anyone know the origin of this myth? The only thing I can think of is
>> very bright starlike objects such as Venus can be seen in daylight
>
>Since Venus is so easy once you know where to look I am inclined to
>believe that the deep well story might have a grain of truth in it.
>Stars like Sirius, Canopus, Acturus & Vega must be close to daytime
>sky brightness levels, a little help might make them visible.
>
>I think I read somewhere the original well experiment was attributed
>to Bradley, but I cannot relocate the reference.
>
>Regards,
>--
>Martin Brown __ CIS: 71651,470
>Scientific Software Consultancy /^,,)__/
>
This whole business is in the sci.astro FAQ. You can't see stars from
the bottom of a deep well any better than you can from the ground.
Sirius may be on the threshold of daytime visibility but Vega is probably
too faint.
Not sure about Bradley; didn't he do his observations at night, or if
during the day, using optical aid? He was trying to look for parallax
and discovered aberration.
It's no problem to see stars using a telescope during the day. That's
the method we are using to test the re-alignment of the polar axis of one
of our major telescopes; 3rd and 4th magnitude stars stand out.
--
Mike Dworetsky, Department of Physics | Bismarck's law: The less people
& Astronomy, University College London | know about how sausages and laws
Gower Street, London WC1E 6BT UK | are made, the better they'll
email: mmd@star.ucl.ac.uk | sleep at night.
Hurricane GRETELLE ( #8 )
Mamy-Rakoto Orstom
Sun, 26 Jan 1997 17:20:19 -0400
Hi,
I've just heard on France-Inter that ~100 persons may have been
killed after hurricane GRETELLE's cruise over the south of Madagascar.
There are also thousands (30000?) homeless people and all the crops
have been destroyed. The risk of another "KERE" like in '92 is high.
I recall that the images are on the following anonymous FTP site:
hostname : melusine.mpl.orstom.fr
directory : pub/incoming/gretelle
-rw-rw-r-- 1 ftp 62 64402 Jan 26 14:05 P97012609.jpg
P97012609.jpg : Color, Sunday afternoon, NOAA-14 ascending.
Hurricane GRETELLE is on the SW corner, at position:
lat = 26.5 S
lon = 40.9 E
Hurricane ILETTA is on the east border, at position:
lat = 14.6 S
lon = 69.6 E
Bye
Mamy RAKOTO
ORSTOM/SEAS HRPT Station
Reunion Island
Re: Can one see stars from a high altitude balloon or a plane ?
Steinar Midtskogen
26 Jan 1997 14:54:03 +0100
[Michael Dworetsky]
> It is apparently true that a high altitude aviator or aeronaut should be
> able to see stars in daylight. I refer to altitudes much higher than
> airliners. I can recall that in the 1950s an autobiography was published
> by a female jet test pilot, with the title _The Stars at Noon_. Sorry, I
> can't recall the author's name.
If we limit the conditions to "noon" or midday, I've also seen them,
down to 4th or 5th magnitude, without any instruments and, unlike her,
with the feet on the ground. It's just a matter of going close enough
to the pole at the right time of year.
--
Steinar Midtskogen Open Systems Consultants a.s (+47) 22 20 40 50
steinarm@osc.no St. Olavsgt. 24, N-0166 OSLO http://www.osc.no
Nomine societatis non dixi
Re: Weather Statistics
Rodney Small
Sun, 26 Jan 1997 09:22:26 -0800
Linda124 wrote:
>
> Help! My boss wants to see temperature, precipitation and wind chill
> indexes for several months previous. Is there any place on the internet
> where I can get this information and print it out in a table or something.
> I need this for Syracuse, NY Please email, Linda124@aol.com. Thanks.
I think the Northeast Regional Climate Center at Cornell University in
Ithaca, New York can help you, although I don't know what you can
download. I purchased some data from them for a nominal fee last year.
Give them a call -- sorry, I don't have the number handy, but you are
close-by and should be able to get it from directory assistance.
Re: Where to find a current map showing distribution of acid rain in North America?
dsalkovi
26 Jan 1997 18:25:58 GMT
fab@direct.ca (Fabrice Grover) writes: > Hi,
>
> I am doing a project on acid rain for a high school Geography course.
> One of the requirements is that I supply a map showing where we find
> acid rain in North America. Does anybody know where I can find a
> relatively up-to-date map containing this information? An online
> resource would be ideal but any source available in libraries would
> do. Please forward any replies to my email account (fab@direct.ca).
> In the case of periodicals, journals, and other publications, specific
> information regarding what issue to look for is particularly
> appreciated.
>
> Thanks for your help,
> Fabrice Grover (fab@direct.ca)
>
For Canadian acid precipitation data, check http://www.ns.doe.ca/aeb/
ssd/acid/index.html.
For US data, check the National Acid Deposition Program's site at
http://nadp.nrel.colostate.edu/NADP/isopleth.maps/95maps.html for
1995 data. Change 95maps.html to 94maps.html for 1994 data. That
should be exactly what you are looking for.
Re: density of dry air
eburger@aol.com (EBurger)
26 Jan 1997 20:25:05 GMT
Dave Baggaley wrote:
>Because water vapour is less dense than air. The ideal gas law
>implies the density of a gas is proportional to its molecular weight.
>H2O has a atomic weight of 1+1+8=10
>02 8+8 = 16
>N2 7+7 = 14.
>Not intuitive, is it?
Right - except for a minor correction to the numbers. Those added values
given above are essentially atomic *numbers* and should be atomic
*masses*. It should read:
H2O has a molecular mass of 1+1+16=18 g/mol
O2 16+16=32
N2 14+14=28
This does indeed make humid air less dense. On a *really* humid day (like
dew point in the 70's F), water vapor might account for about 4% of the
molecules 'in the air' (sorry, I didn't check a table here - might be off
a bit). With mostly N2, dry air averages about 29g/mol. Using
29x.96+18x.04, we get really humid air with 28.56 g/mol. The density is
in about the same proportion. It's a small difference, but with
temperature being equal, the humid air is more 'bouyant', and baseballs
may go a couple more feet!
Tom Ehrensperger
Re: hail in the tropics
Jean-Francois Mezei <"nospam<-jfmezei"@videotron.ca>
Sun, 26 Jan 1997 17:13:35 -0500
Last year, in mid april, as I was cycling near Broome Australia, I was
hit by a rather big thunderstorm which I followed for about 2 hours.
There was hail at one point. (I was glad I was wearing a helmet !)
The temperature went from about 36 degrees down to about 20 at the end.
(It did coincide with the end of the day).
I "entered" the storm thinking it would be one of those 15 minute
quickies to which I am used to, having no idea I would end up following
its path for so long. I had no idea I would end up using the lightning
as temporary lights to show me the way. (my small light on bike was no
help because roads were covered with water). The last 40 minutes to the
roadhouse were in light rain with the actual storm having cohtinued in a
different direction. The hail did not occur right away, it occured a bit
later and thic coincided with the noticeable cooling of the temp.
Broome is at 17 degrees south.
