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Target RA (J2000): 210.193512 and deg Target Dec (J2000): -30.58357 and deg Gaia GMag: 9.867 Programme ID: CH_PR140076 Programme Manager: PATEL PI of observing programme: Benz Title of programme: Axis2 - Terminators Abstract: Exoplanetary atmospheres are 3D objects and various physical processes make them inhomogeneous over different parts of the planet. In particular several studies have demonstrated that different thermal structures and wind patterns over the morning and evening terminator can produce an inhomogeneous cloud coverage over the atmosphere. However a common assumption made while performing transmission spectroscopy of exoplanets is of a homogeneous atmosphere. Considering such an inhomogeneous atmosphere as a homogeneous one can lead to biases in retrieved atmospheric properties. Inhomogeneities in the atmosphere also leave an impact on broadband photometry. In this program we aim to detect this effect directly on the transit lightcurve of three planets. The magnitude of this effect could be as large as 1000 ppm for suitable targets which CHEOPS should be able to detect comfortably. While inhomogeneity can be in chemical structure or aerosol properties we mainly aim to put constraints on asymmetric cloud coverage with CHEOPS observations. We have identified WASP-54 b HAT-P-30 b and WASP-131 b as being the best candidates for detection due to their atmospheric transmission signal transit duration and temperature. Our observations would pave a way for future observations with spectroscopic capabilities to constrain the inhomogeneous atmospheres of these planets. [truncated! Please see actual data for full text]