1. Circumpolar stars are always above the horizon (i.e., they never set).  There are more circumpolar stars closer to the poles.  At the north pole, the whole sky is circumpolar.  Thus, the north pole has many more circumpolar stars than anywhere in the United states, even including Alaska.
   
2. The sky appears and moves differently at different latitudes.  Latitude determines the positions of the Celestial Poles and Celestial Equator along the meridian.  Thus, the motion of the sky relative to the horizon and cardinal directions is determined by latitude.  Also, the amount of the sky that is circumpolar depends on latitude.
   The sky does not vary with longitude, except  for the exact time of rises, sets and transits.
   
3. The zodiac is the set of 12 constellations that line up with the ecliptic and are traditionally used by astrology.  When the sun is aligned with a zodiac constellation, that constellation and neighboring ones are above the horizon during the daytime hours and are not visible.  Thus, the zodiac constellations on the opposite side from the Sun will be easy to see at night.
4. If the Earth had no tilt to its spin axis, there would be no seasons.  Without a tilt, the path of the Sun on the sky would not change with time of year.
5. At the Summer Solstice, the Sun has the highest declination of the year.  In other words, the Sun would appear farthest to the north with a declination of +23.5 degrees.
   At the Winter Solstice, the Sun has the lowestt declination of the year.  In other words, the Sun would appear farthest to the south with a declination of -23.5 degrees.
   At both Equinoxes, the Sun lines up with the Celestial Equator.  In other words, the Sun would appear with a declination of 0 degrees.
6. Precession is the slow wobble of the spin axis of the Earth witha period of about 26,000 years.  The wobble of the tilt of Earth's spin axis is relative to the plane of the ecliptic.
7. This planet should also have seasons because of its tilt.  The seaons would be more extreme than Earth.  This new planet would have greater seasonal differences in declination for its "Sun".   In other words, the seasonal differences in the aliitudes of the Sun and the hours of sunlight are greatert on this planet.
8. The Celestial Equator would be aligned with your horizon at the North Pole.  The North Celestial Pole would be at your zenith and the sky would rotate around your zenith with stars moving parallel to the horizon.  Hence, stars never rise or set/
   At the Equator, the Celestial Equator would run from due East at the horizon, through the zenith, to due West at the horizon.  The North Celestial Pole would lie at the horizon due North.  Stars would rise in the eastern half of the sky and set directly west.  Also, every object would set about 12 hours after rising.
   At 40 degrees north, the Celestial Equator would run from due East to an altitude of  50 degrees along the south of the meridian down to due West.  The North Celestial Pole would be at an altitude of 40 degrees along the north of the meridian.  The sky would rise in the east and slant toward the south until crossing the meridian.  After crossing the meridian, starts would set while slanting to the north.  Stars with declinations greater than +50 degrees would never set, and starts with declinations less than -50 degrees would not be visible.
9. These paths depend on latitude which in this case of 40 degrees north.  On the equnoxes, the Sun rises due east and sets due west.  The Sun spends 12 hours above the horisin and crosses the meridian with an alitutde of 50 degrees along the South.
   On the summer solstice, the Sun rises north of east and sets north of west.  The Sun spends more than 12 hours above the horizon and crosses the meridian with an alitude of 73.5 degrees.
   On the winter solstice, the Sun rises south of east and sets south of west.  The Sun spends less  than 12 hours above the horizon and crosses the meridian with an alitude of 26.5 degrees.
10. If the Earth rotated in the opposite direction once every 24 hours, the starts would rotate WEST to EAST once every 24 hours.  Because the Sun would still move about 1 degree EAST on average every day, the sun would cross the meridian 4 minutes EARLIER every day.  Thus, the solar day would be SHORTER: 23 hours 56 min.
11. Declination is measured positive to the north and negative to the south and is the minimum angular distance between a celestial body and the Celestial Equator.  Right Ascension is the eastward angle from the vernal equinox to the intersection of an object's hour circle with the Celestial Equator typically measured in unit of hours equal to 15 degrees.  The coordinates are similar to latitude and longitude on Earth because they both measure north-south and east-west positions.  Also, declination has a set of positive and negative values just like latitude has north and south.  Howver, right ascension differs from longitude because it is measured eastward only, but longitude has sets of east and west values.  Also, the untis of right ascension are typically hours equal to 15 degrees while longitude is measured in degrees,
12. A solar day is determined by the length of time between meridian crossings of the Sun, while the sidereal day is determined by the motion of the stars.  The mean time between meridian crossings of the Sun  is 24 hours, and the sidereal day is 23 hours 56 minutes.  The difference is a result of the motion of the Sun against the background stars of about 1 degreee per day.