Heliograph stations vs. XIX-century BMs?

June 27, 2003

The same prominent mountaintops in the West which contain some of the oldest benchmarks were also sites of the Signal Corps Heliograph stations. The system was put in place in the last quarter of the 19th century and used sunlight and mirrors to transmit Morse messages, often over 100+ miles in a single bang. One would often find remains of wooden signalling structures up there, inscriptions, etc. E.g. this 1887 copper bolt benchmark is described in the guidebooks as a Heliograph Station :

http://www.geocaching.com/mark/details.asp?PID=KN0449 (I've seen it before I really started to care, and I wonder how I can tell between these two uses for a mountaintop)

Does anybody know if there are any lists of old heliograph locations? There were supposed to be quite a few placed on other continents, too.

June 27, 2003

Links http://www.digitalborder.com/~artpike/helio4.htm

http://www.zekes.com/~hsargent/heliograph.html

HIT THE TRAILS, YIPEE I OH COW PATTI

[This message was edited by COW PATTI on June 27, 2003 at 10:52 PM.]

June 28, 2003

quote:
Originally posted by COW PATTI:
http://www.digitalborder.com/~artpike/helio4.htm

Thanks, the map is great! I also found refs to the regular use of the heliographs only in NM/AZ. So I started digging in the books, trying to figure out where I read about it in the first place.

Kelsey, Michael R. Utah Mountaineering Guide 3rd ed. pp. 194-195

It appears that Kelsey interpreted any remains of possible crew quarters at the highest summits of Utah as an indication that station crews were camped there. As a footnote, he writes that there may some doubts. He spoke with an elderly guy who ran suveys in Henry's Mtns in 1938, and who said that the walls and platforms on Mt. Ellen, in S Utah, didn't exist back then [?]. OTOH Mt. Ellen clearly had a crew stationed there in late summer of 1894, see

http://htg-is.vianet.net/~artpike/helio7.htm

Elsewhere it is claimed that 'In 1884 a heliograph station was placed on Navajo Mountain by U.S. troops under a Captain Thomas', that's on UT side of AZ border, and that in 1887 a station operated at Soldiers' Springs, on North Montezuma Creek, also in SE Utah. I couldn't find anything much about the Signal Corps operations in the Northern part of the state, even though quite a few people describe ruins on Nebo and Ibapah as former heliograph stations. *But* it looks likely that there was some heliography as a part of CGS operations! Citing from http://home.pacbell.net/harryla/harrypage/mountains.htm :

"According to by Robert S. Waite's 1974 Ph.D. dissertation, it was in 1881 that the U.S. Coast and Geodetic Survey began work in the Great Basin on its transcontinental triangulation and reconnaissance survey work west of the 100th Meridian and along the 39th Parallel. High mountains such as Ibapah Peak, Mt. Nebo and Mt. Belknap in Utah; and Arc Dome, Troy Peak and Wheeler Peak in Nevada, were selected as working field stations. Part of the program was to set up and experiment with a mirrored signaling device called a heliograph, see http://209.35.211.132/hiking_outdoor_recreation_guidebook/nevada-great-basin.htm " So the circle may be closing, and the local heliograph stations may be actually the same as the benchmarks from the 1880's survey. I wish I could find a good confirmation for this.

June 29, 2003

Heliotropes and selenotropes were used in geodesy as superior long distance targets, with particular frequency in the southwest, due to the clarity of the atmosphere.

August 21, 2003

quote:
Originally posted by survey tech:
Heliotropes and selenotropes were used in geodesy as superior long distance targets, with particular frequency in the southwest, due to the clarity of the atmosphere.

Thanks, survey_tech! I read through the [lengthy] historical notes on NOAA site, and found a few interesting details to share:

1) light-beam Morse signalling between survey teams wasn't even practiced until ca. 1900

2) by 1900, light-beam geodesy have largely switched to artificial light sources used at night

So geodetists' heliotrops were never really used for transmitting messages, and it would be a mistake to confuse them with geliographs.

Also I learned that selenotropy didn't find a practical use in the SouthWest 'cause it would require custom enlarged mirrors. And that the benefits of long-distance heliothropy might have been exaggerated. It was originally promoted by the French who used it for trans-Mediterranean triangulation. The French distance records were eventually bested by the Americans, but cost-efficiency wasn't all that clear. Quite simply, it was hard to get the right weather conditions for long-range measurements. For the critical 7-station area surrounding Wheeler Peak, it took 10 years of work to complete the dataset!

4.4k · August 21, 2003

I wish I could remember the exact place where it is written down but these stations were also used and in some cases the hand mirror signaling system is what was called the US Calvary Signal Corps.

http://www.army.mil/cmh-pg/books/R&H/R&H-SC.htm

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