  Looking deep into the space in search for truth has been a long time goal of
humanity. With the development of new technologies and observational
techniques, we are now well equipped to see objects billions of light years
away from us. In this study we are going to discuss some of the challenges
radio astronomers face while observing radio continuum sources. We will discuss
issues related to rms noise, confusion, position accuracy, shot noise and how
these issues can affect observation results, data analysis and the science
goals we are trying to achieve. We will mainly focus on the Evolutionary Map of
the Universe (EMU-ASKAP) sky survey, EMU Early science survey and Westerbork
Observations of the Deep APERTIF Northern sky (WODAN), for our study. The study
will also be useful for future surveys like with possible continuum surveys
through MeerKAT (e.g. MIGHTEE) and SKA-1. The late time Integrated Sachs-Wolfe
(ISW) effect detection is one of the major areas of research related to dark
energy cosmology. We will particularly discuss how technical, data analysis and
mapping issues, affect galaxy over/under density dependent science goals like
the detection of the late time Integrated Sachs-Wolfe (ISW) effect through wide
field radio continuum surveys.
