Tribrach OP Target and Focus Calibration

Howdy Nicko

There are many brands and types of optical plumb tribrach out there and they all have the same basic way to adjust for parralax (the condition where the image of the object, crosshair and view point appear to be in the same place or plane).

Turn the receptacle lens to the right or left to make the image of the crosshair appear darkest and more visible and at the same time adjust the zoom to focus the image of the crosshair and the image of your setup point to be on the same plane.

After you have received a few likes and you have made more postings you can upload a picture of your tribrach and give its make and perhaps more help can be made available.

I had one where the optical plummet slid in and out for focusing.
I was happy when we threw that one out.

Scott Zelenak, post: 454243, member: 327 wrote: I had one where the optical plummet slid in and out for focusing.
I was happy when we threw that one out.

I have one of those. It's an older Leica (might be Wild), but is the modern design otherwise. Getting the focus to stay where I slide it is a nuisance, but it's otherwise a workhorse so I keep using it.

Older Leitz & Sokkia tribrachs have a slide focus.
I have 6 of them matched for interchanging instrument and targets.
They are all metal, solid and dependable, like everything, the slide focus is something to become accustomed to.

To clean the lenses (exterior surfaces}, a cotton bud soaked in, we'd call it methylated spirits, and poke through the 5/8 hole in base.
Treat eyepiece same.
Repeat.
I guess any lense cleaning fluid will do. Methylated spirits dries quickly.
Methylated spirits ("metho") is a mixture of ethyl alcohol (95%) and methyl alcohol (%5).
Surprising how grubby those lenses get.

If gunk on the internals then it's possible, but take care. Requires disassembly.

I remember that making me crazy once, about fifteen years back, until I found a spider had spun a web in the hollow of the tripod spindle adapter.

R.J. Schneider, post: 454270, member: 409 wrote: I remember that making me crazy once, about fifteen years back, until I found a spider had spun a web in the hollow of the tripod spindle adapter.

I had that happen to me! I've had laser plummet's for 12 years now. The laser wouldn't shine through the web. Thought the laser went out! Used a plumb bob that day, until I found the web at the end of the day.