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Leica Mimi Prism for traversing

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(@mattf9619)
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Are Leica GMP111 mini prisms suitable for use in traversing to setup survey control??ÿ

Thanks?ÿ

 
Posted : 17/12/2021 1:41 am
(@jim-frame)
Posts: 7277
 

I use the GMP101.?ÿ The GMP111 appears to be similar, but with a plastic support structure.?ÿ I don't know if the glass is the same.

As important as the prism is the way it's carried.?ÿ Whether pole or tribrach, adjustment is critical, and bubble sensitivity is especially import if using a pole (every good-quality tribrach I've ever used has been equipped with an 10-minute or better bubble).?ÿ A high-accuracy prism mounted on a pole with a 40-minute vial in poor adjustment is a good way to get crappy results.

 
Posted : 17/12/2021 8:05 am
(@oldpacer)
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@jim-frame?ÿ ?ÿ The 111 does not have as good accuracy specs as the 101, so probably not the same glass. It seems to me that the 101 provides better results than my GRZ4, but what do I know? Sorry I am negative again.

 
Posted : 17/12/2021 9:31 am
(@norman-oklahoma)
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I also use GMP101s, and am very happy with them. I just received a flyer from Allen Precision which has the 101 on sale for quite a bit less than these 111s.?ÿ Sooooo ... what attracts you to the 111s??ÿ

 
Posted : 17/12/2021 12:21 pm
(@lukenz)
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Only real advantage of the gmp111 over the gmp101 is the bubble location. Jolly hard to see the bubble on gmp101 when using as a mini prism with the small spike they come with.?ÿ Two quite different mounting systems too.

?ÿ

Otherwise brilliant, I've never used the 360 prism my geomax zoom 90 came with for boundary or topo. gmp101 for everything.

 
Posted : 17/12/2021 12:44 pm
(@jim-frame)
Posts: 7277
 
Posted by: @norman-oklahoma

I just received a flyer from Allen Precision which has the 101 on sale for quite a bit less than these 111s.

According to the APE website, the one on sale ($189) is a "Swiss-style" mini, not the Leica GMP101.?ÿ Caveat emptor.

 
Posted : 17/12/2021 1:38 pm
(@norman-oklahoma)
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Allow me to suggest that you put your new GMP101 on this for those times when you want to shoot really low.

image

BTW - I do not hesitate to use the 360?ø prism for boundary ties, and wouldn't want to try doing topo without it.?ÿ True, there is some minute precision loss. But things like monument cap damage, pole tip wear, and pole plumb-ness contribute far more error than the 360?øprism does.?ÿ Even when all those things are in perfect adjustment.?ÿ?ÿ

 
Posted : 17/12/2021 1:39 pm
(@norman-oklahoma)
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Posted by: @jim-frame

According to the APE website, the one on sale ($189) is a "Swiss-style" mini, not the Leica GMP101.?ÿ Caveat emptor.?ÿ

The "swiss style" one is a bit cheaper, but the price they have on the real McCoy is less than it was last year.?ÿ According to the flyer I received the MSRP is $260.

image
 
Posted : 17/12/2021 1:45 pm
(@jim-frame)
Posts: 7277
 
Posted by: @norman-oklahoma

Allow me to suggest that you put your new GMP101 on this for those times when you want to shoot really low.

I have one of those and use it on occasion.?ÿ It can be a bit tricky to hold it plumb while also punching buttons on the DC, but it's better than the little spike that comes with the GMP101.?ÿ I also have a micro-tripod (similar to, but not exactly the same as, the one pictured below) that's fussy to set up but allows two-handed operation of the DC.?ÿ When conditions permit, I prefer the latter over the former.

t
 
Posted : 17/12/2021 2:18 pm
(@rj-schneider)
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The sun shade on the GMP 101. read the Leica white paper on prisms, not sure where the sun shade fits in.

Don't think they covered that with the signal, extinction, or return properties.

 
Posted : 17/12/2021 5:14 pm