Determination of the optimum collector tilt angles for low latitudes is the main subject of this paper.
The monthly, seasonal and yearly average daily values of insolation were calculated for tilt angles ranging from 0-40o.
Microsoft Excel was used to fit equations on monthly, seasonal and yearly average daily insolation with respect to tilt
angles. The calculus method of optimization was employed to establish the optimum tilt angle for low latitudes, 4.86-
13.02 oN, spanning the territory of Nigeria. Expressions for the optimum tilt angles with respect to the low latitudes were
also obtained. The results obtained compare favourable with those in literature and are useful for designing solar
equipment in the range of the low latitudes considered in this study.