The most efficient tilt for photovoltaic panels in Anchorage, Alaska at a latitude of 61.15°:
Your photovoltaic panels need to be angled facing south.
If you're mounting the photovoltaic panels at a stationary angle, such as on your roof, the most efficient angle is 0°.
If you're planning to change the angle of your photovoltaic panels twice per year, the most efficient angle is 35.9° in summer months and 72.7° in winter months.
If you're planning to change the angle of your photovoltaic panels each season, the most efficient angle is 32° in summer months and 78.4° in winter months, and 57.6° in autumn and spring months.