What Are Magnetic Stations?

[+Bos]

Anyone know what goes on (went on) at Magnetic Stations marked by USC&GS, DM = MAGNETIC STATION DISK?.

 

I've looked a lot and found nothing on these except they seem not to be very important in 2005 - as they don't seem to get replaced when destroyed..

What is their significance?

Why were they set?

How are they different from other marks?

How often were they occupied or visited?

For how long at a time?

What equipment used

What parameters measured?

 

I presume these stations were used to investigate the geomagnetic field but found no reference other than data sheets. I infer from scaled location of some that exact location is unimportant. Also precise azimuths seem unimportant as no azimuth marks are indicated.

 

I did find good info on the USGS Geomagnetism and Seismology programs, magnetic and geomagnetic observatories worldwide, A Z-variometers, compass declinometers, transit magnetometers, tri-axial fluxgate magnetometers, and even proton magnetometers. Even found great pictures of this equipment in use on the NOAA web site.

 

Alas, nothing on magnetic stations marked by Magnetic Station Disks.

 

How about someone clue me in.

 

Some links - more upon request:

http://www.geocaching.com/mark/details.aspx?PID=GV0291

http://geomag.usgs.gov/program.html

http://geomag.usgs.gov/observatories/map.html

http://www.photolib.noaa.gov/historic/c&gs/theb1292.htm

http://www.photolib.noaa.gov/historic/c&gs/theb1324.htm

http://www.geocaching.com/mark/details.aspx?PID=TT7719

 

Thanks,

 

Bill BOS

http://www.qrz.com/database?callsign=k3nn

http://www.k3nn.net

[+Kewaneh & Shark]

Here's a USGS website that may answer many of your questions: GEOMAGNETISM PROGRAM SUMMARY. This site may cause you to ask more questions as well.

 

Hope it helps.

 

- Kewaneh

[+Kewaneh & Shark]

Bos -

 

Sorry for the momentary lapse of reason. In my haste to give you a helpful link, it seems I gave you one you'd already researched. Not much help after all...

 

- Kewaneh

[+Klemmer]

Here is a LINK to a thread on here from just a couple months ago on the same subject. Lots of good info in there from Evenfall as always. I didn't re-read tyhe whole thing, but as I recall, it was pretty definitive info.

[evenfall]

BOS,

 

From the best I can research this out and avoid giving a Bibliography longer than the answer, Here is the Gist of what I could find.

 

Prior to the take over in 1970, when NOAA and the NOS basically Swallowed the CG&S (Coast and Geodetic Survey, NGS basically ended their Geomagnetic program. Perhaps as late as 1973, as there are differing sources, the USGS took over the Bulk of that work. It would appear you found the website for USGS coverage, but it does not seem to treat the subject really well with respect to the history.

 

Though it appears that the CGS was involved in taking geomagnetic readings as early as the late 1800's perhaps prior to the early 1900's, the bulk of the work appears to have gone on after World War II. The NOAA history of NGS seems to allude briefly to this Geomagnetic work in places, but even though electromagnetic observations are very important, it really turned out to be not as important to the study of Geodesy as Gravity and Other forms of physical observation and so they gave it to an Agency to whom it would be a better fit to their mission. As such, it is only touched on just briefly in the NGS History.

 

I suppose you could redirect your study of this towards the actual instruments and methodologies, Perhaps some of the College based and private website will allude to the history of this work as well. For the worst part, A Government Career generally lasts only 30 years so the people who may have been players in the geomagnetic game at NGS have likely been long since retired. I would well imagine that the Bulk of them closer to the 35 years ago when the work there ended. That is a pretty cold trail. Best bet would be to see if a Historian at NOAA or NGS knows of or has read of history beyond that which seems to be currently available.

 

As to your direct questions:

 

>they don't seem to get replaced when destroyed.

 

They really have little value beyond their Optically Derived Triangulation Data. Today's Models are GPS CORS and HARN.

 

>What is their significance?

 

They were places to specifically measure geomagnetic values at specific places in the country. This still happens but in different locations and is a real time network. There are also Satellite and aircraft derived observations as well. These stations are simply, Old School if you will.

 

>Why were they set?

 

To create a replicatable location from which data compiled over time could be compared.

 

>How are they different from other marks?

 

Well, They are similar in that they were often Optically Triangulated and so are part of the Horizontal survey network, they are different in that they served an additional duty in the Compiling of Geomagnetic Data. I would imagine that some scouting in a local area and knowledge of the local geological conditions in that given area helped determine the Net Value of a given location, before it was determined to be suitable for making this sort of observation. In other words, It is likely that not just any location is good enough, you have to find the best ones.

 

>How often were they occupied or visited?

 

The frequency may be determined and seeing if a filing was made on the datasheet. That would be the way to reverse engineer that answer anyway.

 

>For how long at a time?

 

Before real time observations became doable, Most any survey measurements ever made are meant to be productive so we, as observers, take only as long as it takes to get the information needed and verify (as in double check) it is as accurate as we can manage. I am unfamiliar with the specific equipment used in that era. This is really pretty specialized scientific work.

 

>What equipment used

 

Well Here is a site which may help with today's take on the question:

http://www.gemsys.ca/Quantum/Scientific/Pr...39;s%20Fury.htm

 

For some super in-depth information have a look at this site and prepare to spend some time reading.

http://www.lund.irf.se/HeliosHome/geomag_magnetometers.html

 

>What parameters measured?

 

Again I think you may find that covered at this link:

 

http://www.lund.irf.se/HeliosHome/geomag_magnetometers.html

 

The USGS may also have outlined what data they collect and how they use it.

 

Good Luck and enjoy!

 

Klemmer, Thanks for the Link but we were talking Gravity in that discussion rather than Geomagnetics. But I think we can agree there is a lot to know about the world. In the news just today we learned that the Earthquake in the Indian Ocean on Dec 26, 2004, the one that caused Tsunami's has been observed to have altered Geodetic measurements reportedly by as much as a half inch globally. I look forward to seeing more fact that support that news flash soon!

 

Rob