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On 1 January 1905, Alfred and his brother Kurt, joined the scientific staff as a technical assistant of the Royal Prussian Aeronautical Observatory at Lindenberg. As the technical assistants, they were to work directly with the observer, Arthur Berson, and with the director of the station, Aßmann, in conducting flights of these experimental aircraft and experimental instruments.
They calibrated the tiny anemometers in the instrument packages sent aloft using a variable speed wind generator. They also regularly checked barometers and barograph in a vacuum chamber and recorded each instrument's standard errors. There were corrections for the corrections. Some measurement devices could not help heating up in still air and strong sunlight, so it had to be corrected yet again, before, during and after each flight.
Alfred's principal employment was to help send these carefully calibrated instruments aloft seven days a week (holidays included) at set hours. The schedule included a flight from 7 - 10 am, one from 2 - 6 pm, and one from 9 pm - midnight. At set times during the year "International Flight Weeks" meant the addition of a flight from 2 - 5 am. Once a month, usually the first Sunday, an instrument package went aloft for 24 hours continuous observations. In the sixteen months Alfred spent at Lindenberg, there were about 400 kite ascents and about 140 captive balloon ascents.
=== Ballooning ===
Berlin flattered itself a world center for aviation under the lavish patronage of the kaiser and the army. Kurt and Alfred had, many times in their childhood, looked up to see the great balloons soaring over the city. The opportunity to go ballooning had been from the beginning one of the main attractions that brought Alfred and Kurt to Lindenberg.
In 1905, heavier-than-air airplane flight was only two years old. The maximum times aloft for these primitive and rickety craft were still measured in minutes. The altitudes were negligible, often only 10 or 20 meters above the ground. Ballooning, on the other hand, offered time aloft measured in hours, altitude measured in kilometers, and suitable for serious scientific work.
==== First flight ====
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