Building sector contributes to 34% of total energy consumption in india, and 28% share in building energy usage is attributable to space-lighting needs. energy requirements for indoor lighting can be reduced through optimal daylight integration, and through control systems for regulating complementary artificial lights in maintaining defined illuminance levels. dynamic light control and building design optimization — both require an assessment of available daylight at various points-of-interest in a facility. the illuminance in the interiors is primarily due to the sky-component of daylight, which depends on the luminance of sky-patch “as seen” through a window at a point in the interiors. building design optimization in pre-construction phase and light control in operational phase need quantification of angular luminance distribution of ambient sky — measured or modeled — for calculating indoor illuminance distribution via daylight. angular sky-luminance distribution dynamically varies with the motion of the sun in the sky-hemisphere, coupled with scattering-inducing local parameters. hence sky-models cannot be applied on a generic basis to all global locations in generating sky-luminance distribution datasets: the actual sky-luminance distribution at a location at any point can highly vary from datasets generated through generic sky-type of the commission internationale de l'eclairage (cie) accepted sky-model. there is a need for higher accuracy in angular sky luminance data; through better models, original measurements or a combination of both. the cost of commercially available device for angular daylight measurement is a deterrent in mass applicability, and low-cost devices can help create a wider network of daylight mapping clusters for creating a global database of angular sky-luminance datasets. in this work, a low-cost concept is developed and validated for measuring sky luminance at discrete sky-positions on a dynamic basis, and its potential towards improving indoor daylight assessment is demonstrated in building design optimization and facilitating building operations. as a primary objective, a low-cost sky-luminance measurement prototype is designed and developed at under rs. 4,000 (about 1/600th of commercial device). calibrated light dependent resistors (ldrs) are used as illuminance sensors, and open source microcontroller- arduino mega 2560 is used for device control, data measurement and data logging. quantitative and qualitative assessment is performed on the measured data towards establishing the validity and reliability of this proof-of-concept device, and the performance is compared with available options. the secondary objective bridges the gap between angular daylight distribution measurement and whole building simulation concepts — by defining a protocol for recommending appropriate models for various measured datasets. sky measurements taken over a 5-month period between nov 2017 and april 2018, representing 143,100 distinct sky-positions in 540 datasets are statistically analyzed. the measured datasets are reduced into indicators for closest sky-type of the cie sky-model, so the indicators may be fed as input to existing simulation software. this approach can help recommend appropriate sky-models for simulating various time-points, as against generic sky-models being used in existing building simulation software. this can help improve accuracy in predicting complementary electric space-lighting requirements, and the annual energy consumption in space-lighting can be predicted with higher accuracy. the tertiary objective designs a calculation-based algorithm for predicting indoor daylight distribution through sky-luminance datasets, and demonstrates improvement in indoor daylight distribution prediction through measurement-based modeling, as compared to using generic sky-types. as an extension of this objective in building operations, the applicability of centralized sky-scanner coupled with computation in real-time spot illuminance prediction and light control is demonstrated as an alternative to actual sensors distributed over a district/campus level. the applicability of the proposed low-cost sky-scanning concept is demonstrated in pre-construction phase for design optimization through improved simulations, and in building operation phase for centralized light control.