I went to a park with a labyrinth. There was a nice sign describing how 7 clerical folks from the Town got together to get the Town to build the labyrinth for the 300 year anniversary. It proceeded to describe that the labyrinth was oriented to "true north" (it was in quotes) and continued to describe alignment to polaris.
So I whipped out the cell phone compass and found the labyrinth is oriented to magnetic north. Declination in this area is about 15 degrees.
It bothers me and I am considering writing a letter to the town to correct this statement. I believe that the use of magnetic is more appropriate to mark the 300 year anniversary.
> So I whipped out the cell phone compass and found the labyrinth is oriented to magnetic north. Declination in this area is about 15 degrees.
>
> It bothers me and I am considering writing a letter to the town to correct this statement. I believe that the use of magnetic is more appropriate to mark the 300 year anniversary.
Okay, will you include in your letter that you are a professional surveyor and you "checked" the orientation of the labyrith with a ... cell phone? In the grand scheme of things, won't that be bad for business if everyone realizes that they can use their cell phones to survey like a pro? :>
Yeah, I understand your feeling Thadd. How can you not say something? I mean Chatham is a water dependant town, or is it "A small drinking town with a fishing problem"?
Every mariner type will understand your letter! If you write it I'll co-sign as Chapter Pres 🙂
Dtp
Well, you really need to do a Polaris sight at the location if you are refuting a claim that it is aligned to Polaris. Or at a minimum a reasonable length GPS baseline, since everybody "knows" GPS is perfect. A mag compass isn't going to cut it.
It is in Thadd's hometown, I'm sure he has a good handle on this 🙂
helped stake a sundial once..
A local college had purchased a two ton bronze functional sundial from an ivy league school back east and hired the outfit I worked for to provide proper alignment for the foundation. We received hand drawn plans from the Dean of Astronomy as to the dimensions and alignment of the sundial. I remember the plans referred to Polaris AND we had to determine the latitude also to calc a tilt or something.
I was the instrument man, the PC was a 'grandfathered' LS (this was 1970) and couldn't count to ten without messing up. He had me set up our best K&E and use the needle to determine 'north' by adding a variance...
I really didn't catch on to anything (being young and dumb) until the owner (engineer) asked me about the job. When I told him how we had laid out the foundation he got really concerned.
We all met out there after dinner on a cold November night and we performed our best Polaris observations. We had a 7 kilocycle WWII surplus receiver (with headphones) to tune in WWV for our times. We were also armed with a current ephemeris for all the calcs. The engineer had a good watch. We calc'd it from his watch AND from the WWV. There was actually no apparent difference, but our base line was less than 1500' long.
The PC's "North" was a minute and a quarter off of astronomical north, and our latitude (scaled from a quad sheet) was actually off by only ten seconds or so.
The PC tried to blame the error on the instrument man (me)...:pinch:
"North" truly has as many definitions as folks you can ask.
helped stake a sundial once..
Several thoughts:
The first step in the job is to determine the accuracy requirements. Even a huge sundial probably doesn't read better than a minute of time, during which the sun moves approximately 15 minutes of angle. I doubt you need arc seconds of accuracy in setup.
Using Polaris, time isn't that critical either - you can get arc seconds accuracy with many seconds of time error.
If you read a transit's compass to a minute and a quarter, that's amazing right there.
Latitude is needed to align the time scale with the sun's path. It might be as crude as aligning with the equator (by site latitude) or perhaps it could have had a scale to adjust it to the sun's path in the ecliptic plane according to season.
helped stake a sundial once..
"The PC's "North" was a minute and a quarter off of astronomical north, and our latitude (scaled from a quad sheet) was actually off by only ten seconds or so."
Not according to the K&E that was used! He was dead on!
helped stake a sundial once..
I always thought the latitude was needed to make the gnomen angle.
And the gnomen is always installed north-south so local apparent noon is due north by the shadow.
It would only bother me if they used Geodetic Mowers to cut the path. 😀
I know the cell phone compass is better than the declination and the entrance lined up well enough to realize that the person who laid out the paver labyrinth probably did it with an iPhone.
I was on jury duty 12 years ago. We were given the tour of the courthouse including the cod fish in the main courtroom hanging from the ceiling heading north. The clerk said he brought in a compass and the cod was off. I raised my hand and described the ever changing magnetic pole.
Nothing beats the feeling of hurling through space on a wobbly mud ball.
Why don't you just gently inform the clerical folks that made the error.
There's more to the the whole concept than it's north orientation 😐
All you guys are a hoot.... lol
You really better handle this or all he11 could break loose !
Surveyor superhero to the rescue !!!
At a certain public project around here there is a nice compass rose, about 6'x6', set in the sidewalk at the entrance to the youth center. As I stood on it, my brain started to hurt, and I realized that the artist had orientated the art work 45 degrees off. There is no real excuse, since all the roads run N-S and E-W, and the direction is obvious.
I wonder if it is an artistic/political statement.
At least I can rest easy knowing that Federal money went to pay for the thing. In other words, thanks to all of you out there for picking up the tab on this one!
