I am considering to buy a handy mini prism for stakeout work. What I have in mind is the Seco (6405-12) Nodal Point but not sure of its trackability when used with a Leica robot. Any experience? Thank you.
When I got my first robot, I felt that I wouldn't need to spend the money for a 360?ø glass.?ÿ Well, it's just about impossible to keep a single retroreflector pointed constantly at the instrument.?ÿ Turn away even for a few seconds, and lock is lost and time is wasted reorienting the target and waiting for the instrument to reacquire the target.?ÿ
I have a couple of mini prisms similar to the Seco (6405-12), but prefer one like this: 
for stakeout.?ÿ Fairly close tolerances can be met by using care in orienting the prism.
Using single prism with tracking is a pain and your precision will suffer.
I would rather spend it on gear than on wages for some poor guy struggling to get the job done with the wrong equipment.
Any experience of the trackability of Seco 360 deg. prism (6401-00-YEL)? As it is a Seco product, I would think it is of good quality and cheaper than Leica 360 deg prism as well. The prism design as an array/assembly of 6 individual glasses provides a feeling that there would be dead spot(s) around the prism.
Using single prism with tracking is a pain and your precision will suffer.
I don't understand why you think precision will suffer.?ÿ I use a miniprism exclusively with my robot, and don't have any precision (or accuracy!) problems.
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If I recall correctly you use Leica -17.5 mini prisms, when you use standard mini prisms robotically the error from pointing of the prism creeps up pretty quickly.
Are you working alone without a 360 prism? I thought you were the user that touted the higher precision lighter weight 360 Leica glass.
True precision aside I have found that working alone with tracking to a standard, moving prism to be an awkward proposition leading to second best results. That loss is what I was trying to speak to, more than say genuine centering error.
Are you using standard or 360deg mini prism?
Standard GMP-101.?ÿ When I started out with a Leica robot I tried using the big 360 glass, but soon got tired of the weight and size and the need to make sure I had one of the yellow arrows pointed at the gun when taking control shots.?ÿ The GMP-101 has a tighter pointing error specification, and it's easy to tell when it's pointed correctly.?ÿ I do lose lock a lot when doing urban topo, but that happened with the 360 as well, and PowerSearch (I forget what GeoMax, which I now use, calls it) allows me to regain lock pretty quickly.
The mini-360 has too short an ATR radius for my needs, so I never bought one.
Trying to wrap my head around this.?ÿ The advertisement calls it a 25mm o/s prism,?ÿ the backplate states it is a -17.5mm prism, which should equate to
a 16.9mm o/s in Leica-speak.?ÿ Which one is it ?
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Thanks for the input, Jim. I am currently using GRZ122 and GRZ4 Leica glass. Yes, they are big and heavy.
The 25 mm would be the diameter, not an offset.
