Re: how to hide a planet
The most obvious 'transparent and incredibly strong' hull is the General products range from the Larry Niven "Known Space" series which he explains (in the course of the volumes) in even greater detail than I go into! It is a single, stabilised, extremely large molecule.
Alternatively, a 'force field' (defined as the forces that hold the subatomic particles together without the particles) if switched on and off fast enough that only light has time to traverse the thickness of the hull, so all matter is maintained/excluded (depending on your viewpoint), would not be as totally clear – a faint mistiness defining the outline from the photons that arrived exactly when the field was in place – but would give a pretty clear view of the cosmos.
Disadvantages are obvious. Sunburn, for one, and vulnerability to laser-type pure radiation weapons. And in deep space it would require more heating than a conventional shiny hull, not tending to prevent energy radiating out, while at close stellar approaches you'd need dark glasses and impressive air conditioning (I take it 'transparent' means all frequencies of electromagnetic radiation, from gamma rays down to long radio? The second option would certainly imply this). If you painted the walls to eliminate the problems you'd lose the surreal ghost ship effect of the crew on loungers sunbathing in the vacuum, and anyway, I can't see how you'd paint a hull that was only there a tenth of the time, and disappeared completely when turned off (I do know how to build the airlock, though. So it would be internal screens put round the sanitary facilities, and the computers on the bridge (so no-one with a good telescope could eavesdrop on your navigation).