- 14.1 Theodolites
- All entries in any event for which an achieved altitude figure is scored shall be tracked in flight by
theodolites of a design approved by the NAR Contest Board. Any tracking theodolite that:
- Is equipped with both azimuth and elevation axes at right angles to each
other
- Can be leveled or adjusted to an otherwise proper plane before use
- Has an accuracy of 0.5 degrees in both azimuth and elevation
- Uses a rifle-sight or equivalent optical sight with or without lenses, or uses a pair of open sights mounted
at least twenty centimeters apart
- Uses crosshairs in the optical or open sight
- Is mounted on a sturdy tripod or other solid base in a manner that does not permit the tracking head to wobble or
otherwise lose its zero-reference under normal use
- Has a provision for securely holding the sights firmly in any desired position, so that the operator may
accurately record the tracking data associated with a flight
- Is capable of tracking to an azimuth of +/-180 degrees and an elevation from 0 degrees to 90
degrees
shall be acceptable for NAR contest use.
The Contest Board must approve theodolites that do not meet all of the above requirements
before they may
be used in a sanctioned activity.
-
- 14.2 Baseline
- Two or more tracking theodolites shall be used on appropriate baselines. The baseline should be between 50%
and 400% of the expected altitudes to be tracked. Thus a 300-meter baseline would be appropriate for 75-600
meter flights. While very low power events may require a baseline under 300 meters, proper care and judgment
should be used before this is done. Longer baselines are strongly encouraged for high-powered or high-performance
models. Proper baselines must be used to track any record setting flight.
-
- 14.3 Tracking
- Models shall be tracked to apogee if practical. When apogee tracking is used, one person shall be designated
to give a mark to the theodolite operators at precisely the instant the entry appears to reach apogee, and the
theodolites shall be locked at the mark. At the discretion of the Contest Director, models may be tracked to
ejection instead of apogee. When ejection tracking is used, it is recommended that the models to be tracked contain
colored tracking powder to create a visible cloud at ejection, and that the theodolite operators lock their
theodolites at the appearance of the tracking powder cloud. It is further recommended that all entries
that are
to be tracked be painted in colors or patterns that will aid tracking. All entries in an event shall be tracked
using the same tracking method (either apogee or ejection).
-
- 14.4 Communication System
- A reliable voice communication system shall be used to link both trackers and the launch
control area, for the purpose of calling marks and for the transmission of tracking data.
-
- 14.5 Data Reduction
- Angular data obtained from theodolite tracking shall be reduced to an achieved altitude figure by
means of a standard system of equations approved by the NAR Contest Board. Samples are included in
Appendix E. All data shall be recorded for all altitude events and flights, including those flights that
may be disqualified; this permits the altitude data to be available in case the disqualification ruling
is later reversed.
-
- 14.6 Error Check
- The error figure as computed by the approved equations must be less than or equal to 10% to be
considered valid and acceptable for competition and record flights. Flights whose reduced altitudes do not
satisfy this constraint shall be scored as Track Not Closed. Flights whose data is incomplete, preventing
calculation of their altitude, shall be scored as Track Lost. All altitudes shall be rounded off to the
nearest meter. Fractions of a meter less than 0.5 must be rounded to the next lower meter; fractions 0.5 or
above must be rounded to the next higher meter. The rounded altitude shall be the official scored altitude.
-
- 14.7 Multiple Stations
- When multiple-station or parallel systems are used, it is only necessary that one pair of trackers (one
at each station) close. In the case that more than one pair of trackers close, the official altitude shall
be computed by averaging all closed tracks, and then rounding them as above. The averaged rounded altitude
shall be the official scored altitude.
-
- 14.8 Novel Methods
- The NAR Contest Board must approve novel altitude determination methods before the results
are accepted for competition.
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- 14.9 Untracked Flights
- Track Lost or Track Not Closed, if it is not disqualified for any other reason, is considered an
unofficial flight. In this case the contestant is entitled to an additional flight, to be made during
the period allocated for tracked flights. At the option of the contestant, Track Lost or Track
Not
Closed may be considered an official flight if it is not disqualified for any other reason. In this
case the flight cannot place but shall receive flight points; except in an event where the score is
the sum of several factors, in which case the flight shall be scored as having an altitude of zero.
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