I'm a "pilgrim" with a Leitz TS20 question

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> Is my instrument broken? Or do I just not understand it's system controls?
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There are probably a lot more sage folks here who have owned that exact model and could provide more insight than I can, but it appears very similar to an old optical Theodolite I owned. That unit has two horizontal adjustment knobs: The lower of the two rotates the azimuth ring...that's the scale you see in the eyepiece. You won't see any increment of the numbers when that's unlocked and rotated.

Once locked though, the upper of the two knobs should result in an increment of the numbers in the eyepiece when the telescope is rotated. Anyone else?

> The vertical incremental function works fine. But when I gently secure both the horizontal & tried to horizontally move left or right, (while viewing my desired progress through the "sunlit" horizontal degree "window", it refuses to incrementally respond.

This sounds like a repeating instrument, so it would have 2 horizontal motions, each with its own lock and tangent screw. When the upper motion is locked and you rotate the alidade (the upper portion of the instrument), the angle reading won't change. If you've tried to lock the lower motion but the alidade still turns, either the lock needs adjustment or it's broken.

> I'm a GC with mostly "shooting level / grade" historical survey experience.
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> My "flea market" purchased Sokkisha TS20 has a side-mount swivel mirror that illuminates a vertical / horizontal degree viewing eyepiece.
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> MY QUESTION IS: There are 2 "locks" on the horizontal "swing", (one of which has/serves an unknown "springish" function) and, only one for the level of the optic eyepiece. All 3 plane adjustments have a set screw and presumably a incremental movement knob.
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> The vertical incremental function works fine. But when I gently secure both the horizontal & tried to horizontally move left or right, (while viewing my desired progress through the "sunlit" horizontal degree "window", it refuses to incrementally respond.
>
> Is my instrument broken? Or do I just not understand it's system controls?
>
> In advance, thanks for your gracious considerations & response.

First, your "springish" movement is working fine. That is too keep a hard push from dislodging the upper horizontal motion from its lock with the bottom.

It sounds as if your unit is working correctly. But you need to understand how the two horizontal circles operate.

The "top" motion should be locked first somewhere near zero on the graduated scale seen through the eyepiece. That vernier is then tuned finely to read exactly zero.

OK, now the entire instrument will now still turn freely and the graduations will not move from zero.

A "back sight" is then sighted through the telescope. Then locked and finely tuned with the bottom lock and vernier.

If you have performed the above correctly, the instrument should be locked and zeroed on a specifically known target (back sight). Once the bottom motion is locked on a target, don't touch it.

At that time the top motion can be unlocked and the telescope moved to a target that you wish to measure the interior angle of it's position (with the instrument at the vertex). Use the vernier to center the target exactly with the crosshairs on the
telescope.

Now read the graduated display for an exact measurement of the angle.

clear as mud, right?

Your instrument sounds as if it's working correctly. It probably needs a good D&C (dusting and cleaning) and calibration.

I concur with the previous answers. Just jogging down memory lane.

I started on the Lietz/ Sokkisha SDM3. Had a built-in edm but pre-total station.

Still see that atomic green background on the angles when the mirror was set just right.

The Sokkisha TS20 I a manual TS

Turning angles is identical to that of an old transit

The mirror located on the standard is to allow light into the instrument to be able to read the circles and verniers when looking thru the microscope.

The mirror will need to be manually adjusted to best reflect sunlight into the instrument.

You will notice a holder located above the mirror. It is to hold a flashlight attachment to shine light into the mirror to reflect into the instrument.

It is also used for a compass arrow attachment.

Feel free to set the instrument up on your tripod and give me a call. I can walk you through the operation if you like. Jeff Whittaker - 503-515-6607

For the rest of you the TS20 was modled by Sokkisha after the old Wild T1A.

>....You will notice a holder located above the mirror.....
> It is also used for a compass arrow attachment.
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>

I used my son's boy scout compass to set the parcel map's PL bearing on the ground (then held that same Azimuth setting) to set my other corner pin. That's seemed a measurably "sloppy" attempt @ accuracy!

If I could find one of those compasses, does/would it have/yield more magnetic detail than just a "North" oriented needle?

These are actually from a Nikon NT-2 from the same era and are similar to those used by all manufactures. It was the last instrument I used while using a Lufkin Crome Highway add tape. It is also the last instrument I've owned that has stadia lines.

I use it to level mobile homes and other buildings because it is so heavy and has small feet that I can sit it on a concrete block or other object and it will stay in place.

The light is merely a flip up style flashlight that takes 2AA batteries and a generic bulb.

The compass was a hit and miss part. Some were excellent and others were not even close.

We had our best results by using a Suunto Compass or a digital compass and rest aside the standard to dial in or check the heading.

B-)

Thanks to/for one & all responders.

It was a rookie error! No blood / no foul!

Turns out the incremental set / movement screw for the "upper horizontal" plane of adjustment was simply turned out to/past its limits of function.

Do I correctly intuit that when using a compass to "check / set" a mag bearing,..that your compass was set up with a measured spatial offset so the instrument metal wouldn't distort the magnetic accuracy?

Seems like a compass attached directly to the instrument would have been thusly problematic.