If you are looking for datasets from amateur astrophotographers to practice with, there are a number for useful resources.
Processing is meant to be fun! If you really need help with a particular dataset, jump on the forums or contact us directly for some pointers - even if you're just using the trial.
Nevertheless the result can look quite pleasing when simply browsing past the image in a Facebook feed.
The Filter module allows for the modification of features in the image by their colour by simply clicking on them.
It doesn't stop there however – the Fractal Flux module can use any output from any other module as input for the flux to modulate.
You can convert everything you see to a format you find convenient. Give it a try!