I can suggest one way you might tie astronomy, biology, and the origins of life together.
Dr. Dave Deamer is a local chemistry/biology professor, who has advised NASA and where to search the universe for life.
Here is a somewhat relevant Scientific American article: https://www.scientificamerican.com/auth ... -w-deamer/
Short story is that life itself needs some way to create cell membranes, before a million years or so of experiments can start stuffing more complicated stuff inside. Using a microscope, soy lecithin emulsified in slightly heated water, and some sort of contrast method (phase contrast, polarization . . .) you can actually see the equivalent of cell membranes self-assembling under the microscope. Looks cool, sort of like a wiggly caterpillar forming out of nothing. The trick is a fatty molecule that has one end that seeks water (hydrophilac) and another end that avoids it (hydrophobic).
Places where that sort of self-assembly is possible (the right kinds of chemicals, as remotely viewed) are places we might find extraterrestrial life.
With respect to a microscope choice, you might want phase contrast -- or at least be sure there is a convenient place to tuck a polarizer between the objectives and the head (there's often space underneath when you take the head off -- or an optional intermediate attachment).