My current favourite phone app is SkyView (I have only used the free version so far). Essentially an astronomy aid if you point it at the night sky it will tell you the names of the stars, planets and constellations that you can see. But of course the stars are still there during the day, it's just too bright for us to see them - other than the sun. And SkyView does work in the day by showing what is currently invisible to the naked eye, enabling you to create some striking montages.
Here's Virgo over the old Deptford Town Hall on Sunday afternoon...
.... and Taurus over New Cross Sainsburys.
During a dull moment at work I did actually point it at my keyboard and spot that the international space station was currently in line with the middle of it - but I'm not going to subject you to that photo!
