Solar astro azimuth

Not sure this has a current ephemeris. 

https://geodesy.noaa.gov/PC_PROD/

I have been trying to make a solar compass attachment for my Zeiss 3306 and have been using this site. 

https://gml.noaa.gov/grad/solcalc/

@rj-schneider 

It has a long time since I used MTEN. The link you provide is to a suite of programs developed to perform reductions/computations of classical (optical) observation data. 

My best recollection of its operation is that it requires the creation of input files consistent with the Horizontal Blue Book. Pretty sure there is no ephemeris included.

Doing a search from the NGS home page fails to find links to “MTEN.” There was a manual.

 I may dust off a PC box and try to test the program. 

While there is a renaissance in astronomical observations due to its use in deflection of the vertical studies in support of geoid modeling, among surveyors it remains an “ancient art” deemed obsolete.

On the many issues related to the determination of azimuth (and more) from optical observations, I would still recommend Mackie’s “The Elements of Astronomy for Surveyors.”  My copy is the ninth edition published in1985. ISBN is 0-85264-244-X.

There is also a digital version of Chapman’s 1919 “The Elements of Astronomy for Land Surveyors” here: https://archive.org/details/elementsofastron00chaprich/page/184/mode/2up?view=theater

Also check UNB’s lecture notes for geodetic astronomy content.

BTW, the US NGS has developed a theodolite-based system for astronomical observations (similar to Daedalus). See:

@GeeOddMike   No one else was participating, so I searched your previous link to the NGS webpage

and found that solar azimuth software package.   Absolutely no clue what's in it.

We appreciate the links you provide.

Ah cool…following along

ive been pursuing this for a little while in the park and backyard with my sokkia tm-1A 

Still haven’t figured out all the pieces yet 

I have created an excel spreadsheet to reduce the observations. And loaded a year of ephemeris data. It’s a complicated thorough computation. But testing never ends  

However I had some doubts in my excel sheet. I’ve reduced several of the observations in Elgin & Knowles Astro83. The output from E&K is quite similar to my computation, 3-4”

I have several distant radio antennas. My issue is morning observations returns 7-12” larger (CW) azimuths than afternoon observations. (Which is also returned by E&K Astro83.) 

It appears that there are few if any current software options.

Now that evening temps are not so cold I’ll be using stars. 

All versions of Carlson Survey that I've used have Solar Observation under the Cogo menu.

1. My issue is morning observations returns 7-12” larger (CW) azimuths than afternoon observations.

   Are you using time or altitude method? The latter would be sensitive to refraction, which is hard to nail down.

@leegreen 

hour angle method. Altitude method is not worth anything. 

Could the top of your favorite tower move that much as the sun heats one side or the other?

I suppose you are familiar with Jerry Wahl's "Revenge of the Altitude Solar"

https://www.cadastral.com/papersl1.htm

@bill93 

Yes that had occurred to me. Even over short time of an hour there seems to be some arcseconds of oscillation

Another possibly useful checking site:

https://www.celnav.de/longterm.htm

I’ve used Stellarium to check my Polaris calculations.  Haven’t used it for the sun.