I'm not sure when it started, really. Never noticed a fever or chills. Perhaps it's when I asked a question about some angle inconsistencies I observed with my Topcon AG2 two plate optical instrument....It might have been Kent who asked: "wait a minute...You're observing a nail at the TOP of a 3' tall survey stake?" At the time, it seemed that this business of surveying was as simple as observing two points in one face; writing the numbers down, and doing a little arithmetic. How cool is that.
This was before I'd heard of Star*net, error ellipses, one sigma, or any of that. One thing led to another, but I never recognized the symptoms really, until this morning when I was doing another solar at my control network site, back sighting to a .032" drill bit (painted white) in the center of a 36" piece of rebar driven two feet or so into the ground almost all the way. While doing multiple D&R observations to it, I noticed that at the distance I was working, the reticle nearly covered the drill bit, but not quite, and as I moved my eye back and forth in the eyepiece, I could see slightly more on one side than the other. It had to amount to at least .002" or .003" either way I thought, although I wasn't sure this just averages out if you just try to make it look balanced on either side. After fussing with both the reticle and optical focus adjustments for 5 minutes or more and doing some numbers on the HP 11c to figure out what this might mean to my current observation, I realized the sun was getting higher and higher and I needed to get on with things. I just had to put one more thing on my list to investigate and eliminate: (parallax in the scope...nothing in the manual about that). Argh.
I think that was the moment I realized I had Conraditis. I did a Google search for possible cures, but came up with nothing, except advice that it could be a very expensive condition involving a penchant to acquire ever more precise total stations and targets, Invar bars, microscopes to read them etc. Once it migrates to using GPS, the costs become astronomical (so to speak), ending usually in those who are afflicted building and maintaining their own personal CORS station(s). I've got the spot picked out already.
Does anyone know of how to cure this condition?
rfc, post: 375549, member: 8882 wrote: Does anyone know of how to cure this condition?
Actually what you are describing is what most good observers do more or less automatically. It's simply the ordinary power of observation, i.e. seeing what is really there before one.
Parallax as you move your eye is a symptom of imperfect focus. Even if it looks pretty sharp, you need to tweak it again.
The floating target is classic.
1925 Royal engineers:
You remind me a bit of a fellow who worked with me for a year or so just for the fun of it. He kept taking various classes from the local community college until he was nearly 80. Sometime around age 72 he completed Calculus II then moved on to Calculus III. Not that he would ever need to know how to do it. He was signed up for a class in astronomy this past semester but they canceled it due to low enrollment.
rfc, post: 375549, member: 8882 wrote: Does anyone know of how to cure this condition?
Nope. Best you can hope for is to identify where it may have been passed to you. For me it was around the time of a prac involving short-range intersection by mutually collimated theodolites. Once you've taken a sub mm trip you don't forget it!
It's a disease, to be sure. I'm 3rd generation surveyor.
Nate The Surveyor, post: 375606, member: 291 wrote: It's a disease, to be sure. I'm 3rd generation surveyor.
As am I.