This will insure that the ``paper trail'' of the data can be followed in the future.

Four observations of ADS 8119 (= HR 4374/4375 = STF 1523 = Xi Ursae Majoris) from Worley (1978) were selected. Observations from a single night are found on a single paper tape output. The last line of these dates is a six-digit number in a format yymmdd which gives the date of the observation. This is converted to the Besselian year, usually on the tape, and these correspond to a single entry.

Four observations were made of ADS 8119 in the Spring, 1974 observing season. Scans of these four outputs is provided in Figures 1-4 below.

The output of an observation consists of at least twelve lines. Outputs for the twelve lines will be explained below:

- The first number is a series of six digits. The first, fifth and sixth digits seems to vary and no correlation with published data is seen --- they could be micrometer readings. The second digit of the first number corresponds to the eye position (e.g., 1 = eyes perpendicular to the line joining the stars, cf. page 8 of Worley 1978). The third and fourth digits correspond to the Delta-m with an implied decimal point between the two digits.
- The second number is also a series of six digits. The first two digits
correspond to the seeing on a 1-10 scale (Worley 1978, p. 8). However, a rather
arcane code is used. A 10 in the first two digits corresponds to a seeing rating
of 2. Similarly, codes of 21, 20, 22, 31, and 30 correspond to seeing ratings of
3, 4, 5, 6, and 7. Digits three and four correspond to the hour angle at the
time of observation, again with an implied decimal point between the two digits.
If digit number five is 1, the hour angle is negative, otherwise it is positive.
The last digit is a code for the microscope objective (e.g., 3 = 12-mm Plossl -
820
*x*, cf. page 8 of Worley 1978). - An individual observation usually consisted of three measurements. Lines 3-5
correspond to the position of micrometer wire 1, lines 6-8 correspond to the
position of micrometer wire 2, and lines 9-11 correspond to the position angle.
A decimal point is implied between the first two numbers of the micrometer wire
reading, and between the last two numbers of the position angle reading. In some
cases more than three readings is taken of the micrometer wires and/or the
position angle (e.g., see five measures of separation in Figure 2). The
difference of the average position of the two micrometer wires is determined,
often calculated by hand directly on the paper tape. Half of this result, times
the screw value (R) in Table 1 of Worley (1978) gives the separation. For
example, consider the values for the first figure:
- The three values of the first micrometer wire (3.026, 3.022, 3.016) yield a mean value of the first micrometer wire of 3.021.
- The three values of the second micrometer wire (2.494, 2.492, and 2.491) yield a mean value of the second micrometer wire of 2.492.
- The difference of these two numbers is 0.529. Half of this, times the screw value (from Worley 1978 Table 1) of 11.04 yields a separation of 2.92".

The next set of numbers correspond to the uncalibrated position angle. The mean of these is modified by the current

*beta*correction. This would be modified every time the micrometer was taken off or put on the telescope. For all of these observations, the*beta*is -6.6 degrees. - The final number is an identifier. It usually corresponds to the ADS (Aitken Double Star) Catalog number, and for all of these observations is 8119.

Each four of these reduced measures is transferred to an index card (at right).
for each target per season. These lines correspond almost exactly to the output
seen in Worley (1978). Note that, in the case of the 1974.348 observation (which
corresponds to Figure 2), the position angle (which was measured five times) is
given a ``:'' indicating a measure of lesser quality. However, it does not seem
to be weighted less in the determination of the mean. It is possible that were
it significantly different from the other values that it may have been given
lesser or zero weight. Finally, the mean is determined, and residuals are
calculated from a published orbit [in this case, Heintz 1966 (actually 1967)].
The mean (which is actually comes from twelve measures) is the final value which
is used in orbit determinations and is placed in the WDS.

References:

- Aitken, R.G. 1932,
*New General Catalogue of Double Stars*, Carnegie Institution, Washington, D.C. - Heintz, W.D. 1967,
*Astronomische Nachrichten*, Volume 289, Page 269 - Worley, C.E. 1978,
*Micrometer Measures of 1,980 Double Stars*, Publications of the USNO, Volume 24, Part 6