DMM is 100% correct.
Absolutely no reason to do the Solars again. Just get the angle between the wrong mark and the right mark and re compute.
Except for one thing:
The entire purpose of this endeavor is to get super good at doing solars. So, taking that into account there's absolutely no reason NOT to do them again.:-)
From a practical standpoint though, I could probably do the solar on the right mark quicker and with less effort than to set up a target on BOTH the wrong mark and the right mark, and shoot the angle. I banged the last round of 16 observations out in less than 14 minutes. Not that speed or efficiency is the main goal here, but just saying.
In all likelihood though, I'll do both. The two marks that need reflectors are only 150 meters apart, easy to get to and there's a nice parking spot right between them. I'll apply the solars I did (late in the day, on the wrong mark), by observing the angle between them, and combine it with another round directly to the mark, hopefully in the morning hours before heat shimmer becomes an issue. That'll give me 32 individual observations, which should be enough to judge my skill level.
150 meters (490+ ft) isn't too bad a distance, but centering will be critical to keep the angle error to less than your error in the solars. I calculate 4 arc seconds per 0.01 ft of centering error, and you have 3 centering errors in measuring an angle, only one of which will be distant enough to be insignificant (1.4 x rms of one?).
As far as for finding information about the mark you actually occupied, have you looked http://vtransmaps.vermont.gov/volgis/map.htm&apos ;">here?
Paul D, post: 366665, member: 323 wrote: As far as for finding information about the mark you actually occupied, have you looked http://vtransmaps.vermont.gov/volgis/map.htm&apos ;">here?
Sure did; That's how I learned of the marks in the first place. I didn't look close enough though, because AA8818 is clearly shown as being further south than where I looked.
Regarding the mark I occupied, my investigation so far indicates that their may be NO State information on it. Apparently, in the 90's, whenever they built a new bridge, it was mandatory to put a disk in one of the abutments. I haven't yet scouted the dozens of other bridges that have been built around here since the 90's (a ton were rebuilt in 2012 after TS Irene), but I have the feeling EVERY ONE of them has an unmarked survey disk in them, lol.