The composer, Rudolf Haken, was most attentive to my editing suggestions regarding Quinquagenarium. Consequently the harp notation accurately depicts the actual execution of the musical symbols making it more quickly accessible.
Unfortunately, one difficulty did not become clear to me until after the performance. Right before the harp enters in measure 8, there is a tempo change. Therefore, it would be wise to insert an extra measure before the harp enters so that the harpist has an opportunity to grasp a stable sense of the tempo before proceeding. Once the harpist begins the arpeggiation, it is necessary for her/him to focus only on the strings (and not the conductor) in order to properly place the hands. Only having an upbeat and downbeat in preparation is risky particularly since the conductor must be relied on to be very clear and consistent about the tempo during that upbeat. There is a distinct possibility that the conductor will err. Any uncertainty about the tempo can cause the harpist to falter.
Originally the part at the beginning of the page below was written so that the octave in measure 35 was doubled in the right hand with the left playing the low D. It was difficult, it not impossible, for the right hand to reach that register. By putting the octave in the left hand, the part became accessible. In addition, by putting the harp flat onto the floor instead of leaning it back on the shoulder, the right hand could reach farther.
To be played with harp flat on floor
As in the case above, this page was rendered more playable by placing the harp flat on the floor due to the use of the low register near the end.