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More Special than "Cincinnati Observatory 1889"?


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I am out in Cincinnati visiting my brother. I had done the prerequisite scouting of benchmarks that I would hope to visit. I had been out for a few hours, had excitedly found all the marks for a triangulation point which I will get to logging and a couple of geocaches. I am driving home and I see a sign for the Cincinnati Obsrvatory. I didn't have the paperwork for that partuclar benchmark (JZ3140), but I had remembered the date the mark was set was 1889, because the name made the date seem quite significant.

 

I took some pictures of the observatory building and walked around back to see if maybe I could find the benchmark without any directions from a sheet. What I saw was this:

 

9db31a74-2436-4d45-8ca6-b23a3f20be9a.jpg

 

I saw the date was 1881, eight years before the reported benchmark. I got very excited that I had found something special. I hd never found a marker placed before 1912, so this was my first 19th century mark. I get home to look on the computer and find that the mark JZ3140 was reported not found 20 years ago. I could not find any report on the geocaching site concerning this marker. I do not know how to navaigate the governement site too well yet, so that may yield some answers for some of you.

 

This marker was obviously not placed there just for kicks. I've never seen any thing posted on this message board like this since I've been looking in.

 

Was this a very significant find or just a pretty neat marker I came to find?

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I am out in Cincinnati visiting my brother. I had done the prerequisite scouting of benchmarks that I would hope to visit. I had been out for a few hours, had excitedly found all the marks for a triangulation point which I will get to logging and a couple of geocaches. I am driving home and I see a sign for the Cincinnati Obsrvatory. I didn't have the paperwork for that partuclar benchmark (JZ3140), but I had remembered the date the mark was set was 1889, because the name made the date seem quite significant.

 

I took some pictures of the observatory building and walked around back to see if maybe I could find the benchmark without any directions from a sheet. What I saw was this:

 

<image>

 

I saw the date was 1881, eight years before the reported benchmark. I got very excited that I had found something special. I hd never found a marker placed before 1912, so this was my first 19th century mark. I get home to look on the computer and find that the mark JZ3140 was reported not found 20 years ago. I could not find any report on the geocaching site concerning this marker. I do not know how to navaigate the governement site too well yet, so that may yield some answers for some of you.

 

This marker was obviously not placed there just for kicks. I've never seen any thing posted on this message board like this since I've been looking in.

 

Was this a very significant find or just a pretty neat marker I came to find?

That is what is known as an "Astronomic Station". The double monument was for mounting an instrument which was aligned along a known axis (a meridian for example). Then observations of the sun wold allow computation of latitude and with timing signals longitude.

 

There's a famous one on the US Canadian border which was was a boundary monument and an astronomic station (as per the the 1915 IBC report) but which has been misinterpreted ever since with various explanations.

 

9ae6e40f-9fc0-469d-b896-9b5ca3554de3.jpg

 

Maybe some one here could explain more thoroughly, how these double stations were used.

 

As you noted, this is better than a mere benchmark. It's a piece of scientific history.

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But it's much prettier than three tacks in a roof that no one can get to! I found a pair of 'True meridian' markers today. Or I could try to figure out how to get to the top of the Weehawken Water Tower (one of the prettiest water towers that I've seen! KV4105)) The two reference marks in the coping, and the eccentric sound like fun to look for. If I could gain admission to the roof, and the dolphin has a severe fear of heights.... But a nail in the tar paper roofing? Set in 1933? KV4032.

Sometimes you wonder how some of these marks found their way into the data base. :laughing:

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The disk is an eccentric point. The actual observations were probably taken from a tripod centered over the nail. It sounds like the disk was set in brick or concrete on the coping, which afforded a permanent setting, but it wasn't practical to make the observations over that point. Likewise, it wasn't feasible to mount a disk in the roofing material.

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That is what is known as an "Astronomic Station". The double monument was for mounting an instrument which was aligned along a known axis (a meridian for example). Then observations of the sun wold allow computation of latitude and with timing signals longitude.

 

Thanks for the insight. I looked on the Observatory's website and there is no mention or picture of the Station, anywhere. I am going to inquire from the Observatory itself about info on what they used this particular one to study.

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This station is described in the 1925 Coast & Geodetic Survey Special Publication 110 "Astronomic Determinations." These pillars were erected to support a meridian transit telescope build by the famous instrument makers Troughton & Simms in the UK. Many of the original astronomic stations established by Survey of the Coast/Coast Survey/C&GS were never tied directly into the triangulation networks. Without going into a lot of detail about the computation of deflection of the vertical is was not always necessary to make that specific observation. The determination of latitude was performed by making 105 observations of 21 pairs of stars and the longitude was by telegraphic connection to the previously established observatory in Nashville, TN combined with the transit observation of selected stars. With the exception of navigation, and very low order charting applications, solar observations were never used for geodetic computations by C&GS.

 

1848_TS_46in_Transit.jpg

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OOhhh......is there a database for these objects?? We can combine out two favorite hobbies...benchmarking AND astronomy!! :angry::D

 

 

DaveD - were these instruments only manufactured by Troughton & Simms in the UK? Or were there any other companies that made them? A friend of ours owns a similiar scope from 1891. But I don't think it was from the company you mentioned.

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I got this reference on these stations but have not tried to find it:

 

“Astronomical Determination of the U. S. Coast and Geodetic Survey and other Agencies”, by Sarah Beall, circa 1925. It lists all the astro and laplace stations in each state.

 

Maybe Dave D. can find a copy in the NGS library (there is an NGS library I hope?).

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Dave,

 

This is a very cool picture of this instrument, thank you.

 

I can follow your explanation a bit on charting relationship of pairs of stars, but is 105 observations a random number chosen, or does it hold some mathematical use. (I'm a chemist, so be patient with me!!)

 

td

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I got this reference on these stations but have not tried to find it:

 

“Astronomical Determination of the U. S. Coast and Geodetic Survey and other Agencies”, by Sarah Beall, circa 1925. It lists all the astro and laplace stations in each state.

 

Maybe Dave D. can find a copy in the NGS library (there is an NGS library I hope?).

DaveD

 

I didn't read your post closely enough. I think your book and my reference are one and the same. (So the IS an NGS Library :ph34r:). And if it contains what my source told me ("It lists all the astro and laplace stations in each state.") it answers elvis3068's question about WV as well.

Edited by Papa-Bear-NYC
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DaveD - I looked at that doc. briefly - and did find a mention of WV in it - is there any better way of knowing if any of these stations are still standing and at what coord?

 

(I admit that being new to this - this may be way over my head)

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Thanks Dave. I noticed that one of these stations was on the old Capitol Grounds - which is now a park/intersection as the complex burned down and moved in the early 1900's.

 

Would those doing work there on the old site have been obligated to move the stations or account for their actions? (another words - is it possible they are still around somewhere)

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They should have noticed the station but older stations often look like rocks, foundations, or other common items that are not important. Even disks disappear often when construction crews either don't notice or don't care. Usually no record is made of the removal.

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