Surveying question

[Dan_Shade]

With my real job, there is a requirement to do an alignment of two "boresights" to the same reference from two different elevations.

It would be sort of like having a telescope pointing out of a second story window, and one out of a window directly below it.  The downstairs one would have to be aligned to the upstairs one, the upstairs one would be fixed.

Is there a way to do this with lasers and mirrors, or prisms or something? 

The way we do it today leaves much to be desired, we currently find a tree or something a half mile or so away and align to it, and it's a real pain to do it that way.

[fstedy]

I would think an elevation rod with a target set at a distance would be the simplest. Whats the application you state boresights?

[Sprucegum]

If you need to do it very often it might be worth your while to build a periscope. I have never seen it nor done it - just shooting in the dark here  ;D

[Roger Nair]

Dan, how precise does the alignment need to be?  Are the sightlines in the same vertical plane? 

Here is a link to Brunson Instruments for a basic tutorial, the last of the great American optical companies, that specializes in industrial control measurements.

http://www.brunsonkc.com/p/LearnCenter.asp

[Dan_Shade]

the goal is to line up to within 0.1 degrees, the sight lines are in the same vertical plane, or very close there too

[SwampDonkey]

You blasting rock for road? Or is this artillery/gun related? I haven't enough knowledge and experience to offer much help. I often like to sketch the problem and brain storm from that. ;D

[Roger Nair]

Dan, since I can only guess about the site and sighting conditions, this is a shot in the dark.  The level of precision is about  .02" per foot, good care must be used for establishing the initial reference line on the machine with some sort of temporary fixtures.  Stretch a string or piano wire across the gauges from the machine towards the tool room window.  Set an engineers transit over the line and sight back towards the machine and adjust the transit so it lines up with with the center line.  Rotate the scope in the vertical axis toward the outdoors through an open window.  Mark sightings near and far on the ground.  Turn transit horizontally 180 and repeat process.  Ideally sightings on the ground will coincide but if not true position is center between the marks at each near and far sighting.  Set transit over the far point and sight to near point and project into the first floor tool room.

I guess that you could use a vertical plane turret laser in a similar process, but I like transits better for purpose of adjustablity and cross checking.  Also I'm a builder not a surveyor or millwright.

Also bench marking the tool rooms could make cross checking an easier task in the future.

[Dan_Shade]

we use a theodolite now to get the upstairs reference, setting up in the middle and flipping to sight end to end to make sure it is parallel.

I'm trying to figure out an easy way to get an accurate line of site downstairs.

I read through that site you posted, Roger, very good info.

BTW, I grew up in Inwood :-)

[Roger Nair]

The simplest method is the most direct, if a small pluggable hole could bedrilled through the floor at each end of the tool room, a plumb bob can be dropped to the lower room.