I went out today and picked up some new toys to play with. Might have to get Dave Doyle to give me some instruction, but I invite any of y'all that are passing through the Valley to stop by and check them out along with some of my other toys.
So what did I get today? Well, here's a list:
- A Wild T-3
- A Wild T-4
- A Kern DKM-3 on an equitorial mount. A very unique instrument.
- An Askania theodolite that is equivilent to a T-4
- A couple of 2 meter Wild subtense bars
etc.
Lots of fun to figure them all out.
> I went out today and picked up some new toys to play with.
So...How does one go about "going out and picking up" those kinds of toys? Like, where do you "go out" to?
Anyway, very nice. I don't think I have ever even seen any of those toys. I hope we can see some pictures soon.
> > I went out today and picked up some new toys to play with.
He actually got some older toys that are "new" to him.;-)
Subtense Bar very interesting 
"toy" and well worth the effort to understand. Online description.
I used to use the Askania model slightly less capable than a T-2.
Your Askania seems pretty rare.
You will enjoy your new toys.
I have 2-Wild T-3's and 2-Wild T-4's, along with the tripods.
Great toys.
I'm thinking you helped an engineering department at some institute of higher education clear out some surplus obsolete gear? You lucky dog you:-) Whatever the case It's good knowing the equipment went to someone who will appreciate and care for it. I got my T-3 awhile back but that's where I stop.... no T-4 in my future the T-3 is quite a handfull. Is there actually a tripod for the T-4? My T-3 tripod is a load... can't imagine what the T-4 pod might be.
Actually came from a friend who is also a collector. He made me an offer I couldn't refuse.
Howdy,
FWIW, here is a photo of an NGS T4 in action. Observer is Ross Mackay, now the Geodetic Advisor Branch Chief.
NGS T-4 in operation showing tripod
Cheers,
DMM
I got a call from my PC this afternoon.
He dropped the T-3 last night. I hope it was after the finished their observations He said that it bent a leveling screw. We use it on a forced centering tripod. We are going to try to adjust it tomorrow. We have a spare T-3 that we may have to put in service.
If I lived in Arizona instead of Ohio I would be looking around for a T-4.
Not for surveying but for comet watching. The T-4 is just starting to catch on among comet seekers. I'm glad to see them put it to a new practical use instead of collecting dust.
Raise Your Hand If You Have Used A Subtense Bar
:stakeout:
Paul in PA
Does school count?
We had to use a subtense bar to determine the baseline distance for one of our trianglation assignments at college.(22+ yrs ago)
Raise Your Hand If You Have Used A Subtense Bar
We have one leaning on a wall in our office @ Washington State DNR... it is old, but I'm not sure if I would call it used.
:-/
Raise Your Hand If You Have Used A Subtense Bar
We had one while I was in the Army. Only used it once. Back in the day it was good for determining distances across rivers, etc.
OUCH!
But trying to look at this with the glass half full, one of us may be able to help the other. Several years ago I bought a T-3 with missing parts hoping that I could fix it up, but have not been able to find the parts I need. So maybe I could supply you with replacement parts or if your's is beyond hope you might be a parts source for me. Let's talk.
This is a pic of the Wild tripod for the T-4. Very very heavy. Has a padded leather top to protect the head.
Raise Your Hand If You Have Used A Subtense Bar
I have used the Subtense bar in anger. As well as using the bar in the conventional way I also used it with dual on-line electronic theodolites for providing scaling in industrial measurement. I used a Kern 1 metre carbon fibre bar together with an Invar 2m bar, The 1m Bar could be rotated on itslongitudinal axis & turned through 180 deg for the removal of addition constant when being used conventionally. With dual theos there is no need to set the bar at right angles as in conventional work.
The book I recomended to Dave Ingram (Askania) which is Surveying (1965 edition) by Bannister & Raymond has an excellent section on the Bar concerning its errors and accuracy improvement. This can be combined with triangulation baseline extension techniques which are also covered in the book. Ideal for micro-triangulation for high precision short range work.
MapTack
Raise Your Hand If You Have Used A Subtense Bar
I think I was in a Subtense Abuse Bar once.
Raise Your Hand If You Have Used A Subtense Bar
I have a wild 2m bar. I spent a several days figuring it out, making repeated measurements with a T2. At 168.889 meters I matched an EDM to a cm. Most books put the upper range at 100 meters to any precision. Then I moved the bar 0.17 m shorter (about 2.5 seconds larger angle) and remeasure. The two measures were 0.172 meters different.
The deal is to turn the angle, only about 40 arcminutes, about 40 times and reject around 30% of them. Std deviation of only 1 second an absolute must. On different days I can repeat the angle to about 0.2 arcseconds. Not easy, but after about 4 different setups the angle/distance was only a few mm different.
Larry Scott
