1990 Wild Heerbrugg T2 mod with DI1000 DISTOMAT

The 1990 Wild Heerbrugg T2 mod.
Figure 1: The 1990 Wild Heerbrugg T2 mod.
This Wild T2 theodolite, also known as the Wild T2 mod, arrived in the collection in September 2015. It was formerly owned by the Maritime Institute Willem Barentsz (MIWB) on Terschelling, where it has been used from 2002 until 2014 for teaching purposes, mainly for traversing and sun azimuth observations using a Roelofs prism (see figure 25 and figure 26). At the start of the new academic year 2015-2016 it was replaced by a more modern Leica TCRA1101 from 2001, which also is used for the same observations.

The Wild T2 mod was the last version of the T2, a theodolite that started in 1926 with the archetype Wild T2. Compared to the previous model T2 the T2 mod had several new features:
  • Automatic compensator for the vertical circle;
  • Handlebar to carry the instrument (see figure 19);
  • Modern look (see figure 1 and figure 2).
Initially it was built with the same metal footscrews as the previous model, but later these were replaced by the type of footscrews found on the Wild NA2 and modern Wild N3. Around the same time the well known dome shaped metal container was replaced by the red synthetic carrying case (see figure 3, figure 4, and figure 6) known from later total stations as the Leica TCRA1101. Two red lines, also new to this instrument, on the yoke and base assist in proper alignment of these parts in order to place it in the case (see figure 20). No further changes would be made and the example shown here is the final model of the T2 before production stopped in 1996.

Compensator
The T2 mod was not the first Wild theodolite with a compensator for the vertical circle. In the end of the 1950s the Wild T1A was the first to show this feature. The main difference with the compensator featured on the T2 mod is that the latter is a mechanical one, whereas the one on the T1A works with a liquid.


The 1990 Wild Heerbrugg T2 mod from the other side.
Figure 2: The 1990 Wild Heerbrugg T2 mod from the other side.
Accuracy1
This Wild T2 universal instrument is equipped with glass circles (90mm diameter horizontal and 70mm diameter vertical) and a optical reading mechanism. The T2 mod has a compensator for the vertical index (see figure 11). With 70mm diameter the vertical circle of this final model T2 is substantially larger than that of the archetype model T2, while the horizontal circle remained the same.

This T2 mod has centesimal circles divided down to 20c (0.20gon) intervals, can be read using a micrometer directly to 1cc (0.1mgon) and estimated to 0.1cc (0.01mgon, see figure 23), although that is beyond the T2's accuracy. The circles are illuminated by two distinctive rotating mirrors: one directly on the secondary axis and one at the base of the instrument (see figure 17 and figure 18).

The accuracy of the compensator for the vertical circle increased from 1" at the T1A to 0.3" in the T2 mod.1

EDM
The T2 mod could be equipped with various types of EDM (Electronic Distance Measurer). For this the lower optical bead has to be removed and replaced by a dedicated mounting bracket (see figure 24, figure 7, and figure 8).3 This particular instrument came with a Wild Heerbrugg Di1000 distomat. It too originates from around 1990 and still is in working order (see figure 10). In contrast to the DI3S the Di1000 consists of a single unit (the DI3S has a separate controller). Its accuracy is stated as 5mm+5ppm for normal measurements and 10mm+5ppm in tracking mode.2 Taking a measurement in normal mode takes 5 seconds. In tracking mode the first measurement takes 3 seconds and each following one 0.3 seconds.

The Di1000 EDM came in its own case, together with the original battery, charger, cables, raincoat and manual (see figure 5). The Di1000, power cable and battery also fit in the case of the T2 mod (see figure 6).


Notes

[1]: Wild Heerbrugg, Wild T2, Universal Theodolite with automatic index, Instructions for Use, (Heerbrugg, 1981), p.10.
[2]: Wild Heerbrugg, Distomat Wild Di1000: Gebrauchsanweisung, (Heerbrugg, 1987), p.51.
[3]: Please note that the bracket shown here is for the older types of Wild EDM and lacks the small depression for the electrical connector of the Di1000. In order to avoid short circuiting the Di1000 a piece of electrical isolation tape should be pasted on the surface of the bracket.

If you have any questions and/or remarks please let me know.

The Wild T2 mod with its original case.
Figure 3: The Wild T2 mod with its original case.
 
The Wild T2 mod in its original case. The open spaces are to store the accessory distomat.
Figure 4: The Wild T2 mod in its original case. The open spaces are to store the accessory distomat.

The Wild Heerbrugg Di1000 distomat (EDM) came with its own case.
Figure 5: The Wild Heerbrugg Di1000 distomat (EDM) came with its own case.
 
The Wild Heerbrugg Di1000 distomat and battery in the T2 case.
Figure 6: The Wild Heerbrugg Di1000 distomat and battery in the T2 case.

The lower optical bead can be removed to mount the Wild distomat using a dedicated bracket.
Figure 7: The lower optical bead can be removed to mount the Wild distomat using a dedicated bracket.
 
The adapter plate for the Wild Heerbrugg EDM mounted.
Figure 8: The adapter plate for the Wild Heerbrugg EDM mounted.

The Wild Di1000 distomat mounted on the T2 mod.
Figure 9: The Wild Di1000 distomat mounted on the T2 mod.
 
Despite being from 1990 the Wild Heerbrugg Di1000 distomat still works.
Figure 10: Despite being from 1990 the Wild Heerbrugg Di1000 distomat still works.

The black button of the Wild T2 mod resets the compensator in a similar way as in the Wild NA2.
Figure 11: The black button of the Wild T2 mod resets the compensator in a similar way as in the Wild NA2.
 
The lever locks the horizontal circle, the knob at the lower left sets it.
Figure 12: The lever locks the horizontal circle, the knob at the lower left sets it.

The serial number indicates this Wild T2 mod dates from 1990.
Figure 13: The serial number indicates this Wild T2 mod dates from 1990.
 
The adjustment screw for the compensator is hidden behind a small cover.
Figure 14: The adjustment screw for the compensator is hidden behind a small cover.

The lower optical bead has a lever to turn the internal mirror for reticle illumination.
Figure 15: The lower optical bead has a lever to turn the internal mirror for reticle illumination.
 
The reticle illumination mirror can be seen through the objective.
Figure 16: The reticle illumination mirror can be seen through the objective.

The mirror for the vertical circle of the Wild T2 mod.
Figure 17: The mirror for the vertical circle of the Wild T2 mod.
 
The mirror for the horizontal circle of the Wild T2 mod.
Figure 18: The mirror for the horizontal circle of the Wild T2 mod.

The Wild T2 mod came with a new feature: the carrying handle.
Figure 19: The Wild T2 mod came with a new feature: the carrying handle.
 
The electrical connector and red lines to properly align the instrument for storage.
Figure 20: The electrical connector and red lines to properly align the instrument for storage.

The erected view through the telescope of the Wild T2 mod.
Figure 21: The erected view through the telescope of the Wild T2 mod.
 
The optical plumb of the Wild T2 mod is a simple cross.
Figure 22: The optical plumb of the Wild T2 mod is a simple cross.

The vertical circle (left) reading 98.94938 gon, the horizontal circle reading 186.99594 gon.
Figure 23: The vertical circle (left) reading 98.94938 gon, the horizontal circle reading 186.99594 gon.
 
The dedicated adapter for the Wild Heerbrugg EDM, the green part is not used for the Wild T2 mod.
Figure 24: The dedicated adapter for the Wild Heerbrugg EDM, the green part is not used for the Wild T2 mod.

MIWB Students starting a traverse with the Wild T2 on a wet November day in 2010.
Figure 25: MIWB Students starting a traverse with the Wild T2 on a wet November day in 2010.
 
MIWB student taking a sun shot with the Wild T2 and the Van Leeuwen Roelofs prism in 2011.
Figure 26: MIWB student taking a sun shot with the Wild T2 and the Van Leeuwen Roelofs prism in 2011.

Surveyor's crosses Geodetic Sextants Theodolites Total Stations Levels Standards Tools Firms
19th C. SDL 1919 K&E 1926 Zeiss RThII 1924 Zeiss Th1 1929 Wild T2 1937 Wild T3 (astronomic) 1939 Wild T3 (geodetic) 1943 CT&S Tavistock 1948 Wild T1 1952 Wild RDH 1956 Wild T0 1961 Wild T1A 1961 Wild MIL-ABLE T2 1962 Wild T2 1963/76 Wild T2 - DI3S 1963 Wild RDS 1966 Kern DKM2 1969 Wild T2E 1976/79 Wild T2 mod - DI4 1990 Wild T2 mod - Di1000 20th c. Askania Tu400