I'm a beginner in Astronomy. What do these latitudinal and longitudinal lines and accompanying hours and degrees represent (in blue: +12h , +11h.. and +45° +60°.. , in orange: +330° , +15°) ?
The blue grid shows equatorial coordinates: right ascension (0h..24h) and declination (-90°..+90°). Declination is 0° on the celestial equator and ±90° at the celestial poles. The Sun's right ascension is 0h at the March equinox, 6h at the June solstice, etc.
The orange grid shows horizontal coordinates: altitude (-90°..+90°) and azimuth (0°..360°). Altitude is 0° on the horizon and +90° at the zenith. Geographic north is azimuth 0°, east is azimuth 90°, etc.