The Gran Telescopio Canarias (GTC), La Palma, Spain, is currently the largest (10.4m) and one of the most advanced optical/infrared telescopes in the world. It gathers several innovative visiting instruments. These instruments extend the exploitable capabilities of GTC beyond that covered by the common-user instruments (e.g. by providing high time resolution or high spectral resolution). Here we describe the visiting instruments HORuS and HiPERCAM and their main scientific results.

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