In article E9sld.110274$cJ3.88730@fed1read06,
(Dan Mckenna) wrote:

to have a second observer in case I lost track or wrote
down the wrong reading

That might well be the reason for the second pillar, as a confirmation of
the readings, especially considering the short distance between them.

The balloon would have been launched from the same point, i.e. not more
than a few feet from the theodolites.

as the ascent
rates for a standard balloon and fill are known.

I wonder if that applied in 1942? No reason why not, I suppose.

In article E9sld.110274$cJ3.88730@fed1read06,
Dan Mckenna wrote:

rates for a standard balloon and fill are known. I would feel better as
an observer just to have a second observer in case I lost track or wrote
down the wrong reading, as I have. I find the mistake when I plot the
data if it's really off, but a second observer would really help.

I had 2 mini-cassette recorders - one with a timed count so I didn't
have to keep an eye on the clock. The other, with voice activation, for
recording the elevation and azimuth. Was a great idea, esp. with any
strong winds aloft. This one sat on the base of the theodolite - right
next to my mouth. That made it so much easier to record the data!



Pete

In article .com,
(Jim) wrote:



The US Federal Meterorlogical Handbook #3 is a good reference

http://www.ofcm.gov/fmh3/text/default.htm


Thanks for that link. Can't get the illustrations to show themselves.
Sometimes I curse Internet Explorer!

I have also found a New Zealand site with detailed 'how to' on Pibal. So
now I know what it means :-)

Brian.

Pete Ware wrote:

In article E9sld.110274$cJ3.88730@fed1read06,
Dan Mckenna wrote:

rates for a standard balloon and fill are known. I would feel better as
an observer just to have a second observer in case I lost track or wrote
down the wrong reading, as I have. I find the mistake when I plot the
data if it's really off, but a second observer would really help.

I had 2 mini-cassette recorders - one with a timed count so I didn't
have to keep an eye on the clock. The other, with voice activation, for
recording the elevation and azimuth. Was a great idea, esp. with any
strong winds aloft. This one sat on the base of the theodolite - right
next to my mouth. That made it so much easier to record the data!

Pete

What amateur astronomers who are occultation observers do is have a
shortwave playing WWV time signals and record their voices and the
signals. You need good reception, of course. It eliminates problems
with variations in tape speed, but I don't know if you need that
degree of accuracy for theodolite work.

Cheers,
Russell
--
All too often the study of data requires care.

On Sat, 13 Nov 2004 23:53 +0000 (GMT Standard Time),
Brian Salt , in
.uk wrote:

+ Thanks for that link. Can't get the illustrations to show themselves.
+ Sometimes I curse Internet Explorer!

Dude. Firefox. Seriously.

http://www.mozilla.org/products/firefox/

James
--
Consulting Minister for Consultants, DNRC
I can please only one person per day. Today is not your day. Tomorrow
isn't looking good, either.
I am BOFH. Resistance is futile. Your network will be assimilated.

In the past I used a darkroom timer that was set to go off every minute.
The challenge has been on the days when the balloon will move out of the
field or through scattered clouds. If I keep my eye to the theodolite
and keep the elevation and azimuth knobs moving at a constant rate then
momentary loss say due to clouds, power lines or UFOs can be worked
through as I can pick it up on the on the other side as long as I keep
turning the knobs.

I have been able to peak the signal using my dish and
read the elevation and azimuth display to re acquire.

I also predict the balloon track by using the NOAA READY predicted ETA
40 km sounding, running it through a program called balloon track and
then running my own program that calculates the apparent position from
my location. sometimes thats all I need.

The other week I saw a burst a little past sunset and it was
spectacular when the balloon turned in to a field of stars.

I will obtain a voice recorder.

Dan




R. Martin wrote:
Pete Ware wrote:

In article E9sld.110274$cJ3.88730@fed1read06,
Dan Mckenna wrote:


rates for a standard balloon and fill are known. I would feel better as
an observer just to have a second observer in case I lost track or wrote
down the wrong reading, as I have. I find the mistake when I plot the
data if it's really off, but a second observer would really help.

I had 2 mini-cassette recorders - one with a timed count so I didn't
have to keep an eye on the clock. The other, with voice activation, for
recording the elevation and azimuth. Was a great idea, esp. with any
strong winds aloft. This one sat on the base of the theodolite - right
next to my mouth. That made it so much easier to record the data!

Pete


What amateur astronomers who are occultation observers do is have a
shortwave playing WWV time signals and record their voices and the
signals. You need good reception, of course. It eliminates problems
with variations in tape speed, but I don't know if you need that
degree of accuracy for theodolite work.

Cheers,
Russell

"Brian Salt" wrote in message
k.co.uk...
In article ,
(Martin Rowley) wrote:

That is the method I felt would be used, but, as you say, the baseline
of
22 feet is not a useful distance.

.... I've now found a reference to the required minimum baseline: I
couldn't find it when I replied originally. To quote " by simultaneous
observations from the ends of a base line - the base line must be at
least 1/2 mile in length (hence the 'telephonic link') ....
This was only used when highly accurate upper wind finding was required
and now that I know where the airfield was (see below), and what it was
used for (mainly Fighter work) this can't be applicable to this
occasion.


I'm curious: *which* airfield in Devon are we talking about?
Harrowbeer Airfield, some 9 miles north of Plymouth.

.... thanks for that: I'm not sure if you are aware of the following site
(or you may be connected to it), but I found the history very
interesting in the context of your question.

http://www.bucklandmonachorum.org.uk...Harrowbeer.htm

It appears from this that the base was (for its short life) principally
a Fighter Command base. In this case, the Met Office would have in most
cases (always exceptions of course), be co-located with ATC. This was
standard Fighter Command practice ... see
http://www.controltowers.co.uk/Tower%20Designs.htm, because the MET
section had its sole role in the support of the airfield controller (low
cloud, fog, wind etc.) and so all the meteorology stuff was close-by.

In the other 'major' commands (e.g. Bomber, Coastal, Ferry & later
Transport), the Met Office tended to be apart from ATC (but not
necessarily a long way away, just enough to remove the instrument
enclosure etc.), and the pillars for theodolites etc., would not
necessarily be near/on the ATC/Watch Office. This was because the work
of the Office would be to brief aircrew, maintain links with duty
squadron/operations staff etc.


So what is the single theodolite method?

.... I think this has been answered elsewhere in this thread - for a
station as small as this, they wouldn't have had the need for high
accuracy of upper winds and this method (single) can give fair results -
Rodney and others have described it well: it does assume a constant rate
of ascent of the balloon, which for various reasons is not always true.


There is no mention of a Nephoscope is the information we have - and
it is
not mentioned on the plans of the watch office/control tower.

.... no, it probably wouldn't be mentioned as such in those plans- but it
was a long-shot anyway, and again I can't think they would have had the
requirement. Don't waste time on that. There might have been a comb
nephoscope??


Perhaps the need for 2 pillars was to use whichever would be better to
avoid the projection of the balloon filling room, which projects some
8
feet above the roof upon which the pillars are fixed. I can't imagine
that
the room for cause any obstruction, but maybe it was 'belt and
braces'!

.... this is much more likely. Perhaps the ATC/Watch Office was hurriedly
put up after the raids on Plymouth (as the airfield was built to a
standard Air Ministry design), and they then found the pillar was not
optimal. A second could have been built quickly. Or it may have always
been on the original plans - I have no knowledge of that: what I do know
is that if the low level winds were strong, the balloon once released
could go off quickly downwind at a low angle of elevation, such that
near obstructions would block the line of sight.


What would a balloon have be used for, given the technology available
in
1941-42? Determining cloud base, I suppose, as well as finding the
upper
winds?

.... balloons were often used (without theodolite) to measure the base of
low cloud - indeed, I would guess that this was the most often use of
such - smaller balloons than those used for the pilot balloon, with a
slightly slower rate of ascent - circa 400 ft/min, as opposed to 500 or
greater for pilot balloons. All you needed was the balloon, a stop watch
and the Mk1 eyeball to time when the balloon was lost into the base of
the cloud (or through the fog.)

.... as you are in Devon, you might consider making contact with the Met
Office archives (once they've settled down early in the New Year after
the move from Bracknell). They *may* still have the old Daily Registers
and other station information ... all MetOffices had to have plans of
where instruments etc., were. Inspection of the Registers (if still
extant) might show some useful information relating to use of
instrumentation.

See:- http://www.metoffice.gov.uk/corporat...ary/index.html

I have a couple of photographs here (in old publications of the time)
which show the operation of pilot balloon equipment - don't know how
well they would scan, but if you are interested, let me know and I'll
have a go sending them on.

all the best,


Martin.


--
FAQ & Glossary for uk.sci.weather at:-
http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm

In article ,
(I R A Darth Aggie) wrote:

Dude. Firefox. Seriously.

I tend to agree, especially since the new version has just been made
available.

Investigating...

In article ,
(Pete Ware) wrote:

*From:* Pete Ware
*Date:* Sat, 13 Nov 2004 17:33:18 -0500


I had 2 mini-cassette recorders - one with a timed count so I didn't
have to keep an eye on the clock. The other, with voice activation, for
recording the elevation and azimuth. Was a great idea, esp. with any
strong winds aloft. This one sat on the base of the theodolite - right
next to my mouth. That made it so much easier to record the data!


Some people have all the technology!

In article ,
(Martin Rowley) wrote:

... thanks for that: I'm not sure if you are aware of the following
site (or you may be connected to it), but I found the history very
interesting in the context of your question.

http://www.bucklandmonachorum.org.uk...Harrowbeer.htm

You are correct. That is the Buckland Monachorum site maintained by my
son-in-law.

Take a look at the link, or go directly to this one
www.rafharrowbeer.co.uk

It appears from this that the base was (for its short life) principally
a Fighter Command base. In this case, the Met Office would have in most
cases (always exceptions of course), be co-located with ATC. This was
standard Fighter Command practice ... see
http://www.controltowers.co.uk/Tower%20Designs.htm, because the MET
section had its sole role in the support of the airfield controller
(low cloud, fog, wind etc.) and so all the meteorology stuff was
close-by.

Started out as an Air Sea Rescue station, but rapidly became full member
of No 10 Group, Fighter Command. Everything from Walrus, to Hurricane, to
Spitfire, to Typhoon, plus a few others. Even had a visit from President
Truman - bad weather force a diversion of his DC3 and he had to land here.

Regarding the theodolite pillars, they are on the original plans for the
Watch Office (a standard design of the day). Harrowbeer is exposed (not as
much as some!) and is subject to cross-winds, fog and rain. When the wind
blows hard it is really rough up there, so any balloon launch would be
near horizontal. Would they bother in such wind conditions, I wonder?