Practice Finding Nawth

Nawth is overdue.

Nawth is thataway.  Yes.. It is..  Not this away.  Thataway.

Would surveying maps have turned out differently had the overgrown aggravation that ended in 1865 had a different outcome?

For most of here, north is the direction you point when you point towards the nearest place in Canada from where you are.  Does not hold true in Detroit, however.

@holy-cow 

Nor New Yawk.

While it is convenient to have known points on a N-S line, a pair at any azimuth can provide a useful check on your astro work,

OK, really pissed....I just spent 30 minutes writing a detailed post about this, and when I went to "add reply" it said..."Forbidden, appears to be spam" or something like that, and I lost all of my work. WTF

A N-S line does not provide any better check on an azimuth than a line in any other direction. When you do an astro obs for azimuth you are determining the azimuth to the celestial object at a certain instant of time, you need an angle to the ground mark to get an azimuth, so it makes no difference if it is N-S or not.

Also, I would consider an azimuth mark at a triangulation station to be third order. I believe they were mostly observed during the daylight, from the top of the tower if there was one, doing 4 sets (as opposed to 16 or 32 sets to main-scheme stations). So, any small error in instrument collimation over the station mark would contaminate the results as they were usually not too far away. And they are usually concrete posts, subject to disturbance/movement over the many decades. So I have never really trusted them other than for a low order traverse.

In 1986 I did a bluebook project in Prince William County, VA (GPS087). 80 new stations. At the time, we considered it more efficient to observe Polaris to azimuth marks rather than do another GPS occupation, so I did 80 polaris azimuths to second order specs using a T3 to nearby azimuth marks. But, when I check datasheets for any of those stations, the azimuth marks are described in the description, but no azimuth is given on the data sheet. For an example of a station with an azimuth listed, see KY3089 (in the Pittsburgh area). If you want a good laugh, go to the 2008 recovery for this station.

I used to be able to extract observations from the NSRS via Telnet, but that was removed in the early 2000’s due to security issues. In 2003 I was doing some bluebooking in the same county for a local surveyor, and I extracted the observations at station LINTON HALL (HV8201) since I still had access to do that. It shows the azimuth I observed in February of 1987:

(If I try to paste an image here the whole post is rejected as spam)

h z-GPS087 LINTON HALL 19870219 11438769 LINTON HALL AZ MK N 1.5 1 N 2950157.5 PRINWILL

So, the azimuth is in the NSRS database, but does not show up on the datasheet. Not sure if it ever did. I did a lot of work observing 80 polaris azimuths, going out every clear night while still trying to do my day job, then computing/reducing/formatting for submittal with the bluebook GPS obs.

As an aside, after access to the NSRS via telnet was shut down, I have asked a number of NGS people over the years to please add that functionality to a web page, but it has never been done, at least not publicly available to my knowledge. We should be able to extract any observations done at a station, whether GPS, conventional, astronomical, leveling, etc. I believe the leveling data is available, at least as a beta. I really hope they add the functionality to get GPS and conventional data as well.  

@john-hamilton ks 

Don't give up on it. I read your publications on azimuths and other topics many years ago and learned a great deal.

You are someone who should be listened to.

@john-hamilton ks 

Don't give up on it. I read your publications on azimuths and other topics many years ago and learned a great deal.

You are someone who should be listened to.

Thanks, nice to be appreciated. I wrote it up again in word so that I would have a copy. Anytime I tried to include a jpg I got a message that it was spam. So I just pasted the single line with the azimuth info in the above. 

If anyone wants to try and do astro obs at night just for fun (or work), there is a really cool web site that shows hour by hour the sky conditions for a site you can select. 

https://www.cleardarksky.com/

@john-hamilton 

Yes. The specific problem in the prior posts was to establish a north-south line -- a meridian. One was for the anemometer to be mounted on an automated weather station. Another had to do with a survey, but one of the replies noted establishing north for cell towers. The astro methods mentioned were solar and Polaris observations.

In earlier posts, historical meridian lines with surviving north and/or south points were discussed.

It seems to me that determining personal error or learning a new skill would be valuable. 

 AI2171 and AI2163, the two marks at Columbus County Muni, are rigorously determined geographic positions that happen to lie very nearly on a meridian. Both are stability C, subject to surface movement. 

But, by providing a reliable check, they and similar pairs should provide valuable practice for learning or honing the skill of determining geodetic north.

@john-hamilton 

I started to see that too. 

At the Fall 2022 Surveyors Historical Society meeting in Harpers Ferry there was a very interesting talk by a woman about some meridian monuments on Nantucket . I wish they had a copy of her presentation online, but I can't find it. But here is an article about it in The American Surveyor. I have been to both islands, but did not know about this when I was there. 

https://amerisurv.com/2022/03/13/exploring-the-mystery-of-nantuckets-meridian-stones/#:~:text=In%201840%20the%20astronomer%20and,stones%20have%20seen%20better%20days.

@john-hamilton 

Welcome to The Club of the Forbiddens.

Wendell is aware that the spam filter on his newest version of things is wound a bit too tight.  Surely he will fix this before jumping from SurveyorConnect to RPLS.com.

It has nabbed me close to a dozen times already.

@john-hamilton 

Welcome to The Club of the Forbiddens.

Wendell is aware that the spam filter on his newest version of things is wound a bit too tight.  Surely he will fix this before jumping from SurveyorConnect to RPLS.com.

It has nabbed me close to a dozen times already.

Wouldn't be so bad if you didn't lose everything you typed...

She has some web pages about the Nantucket stones.

https://www.savethemeridianstones.com/

https://www.change.org/p/save-nantucket-s-meridian-stones

Her longer paper (24 pgs double spaced w/ 4 pictures) is on the flash drive distributed at the SHS conference. I won't link it here, but will send a dropbox link to anyone via private message on this site.

Sounds like a fun project for you Math Teacher. Maybe a local can loan you an instrument to practice on.

As for me, I hope to never again grind out solar observations and calculations. I enjoyed it at the time, but there is a time to move on.

I'm hoping to play around with some celestial observations soon with my "still new to me" Wild T-2 theodolite. I've been playing around with it in the daylight to get familiar with its controls.

I'm hoping to play around with some celestial observations soon with my "still new to me" Wild T-2 theodolite. I've been playing around with it in the daylight to get familiar with its controls.

@mightymoe 

Heck, Moe, I don't even go out on the beach anymore. I observe the sun in the shade from the porch and don't see Polaris 'cause the porch faces South.

Now, in prior years, coming home from the beach on US 220 at night, I could observe Polaris for about 90 minutes from Rockingham to Greensboro.