Summary of the Apparent Motion of the Stars From Syracuse, NY looking North From Syracuse, NY looking East From Syracuse, NY looking South Reference to a Figure 1.4 in the text The five ”rules” regarding the apparent motion of the stars.

Looking North Stars appear to circle CCW around Polaris (NCP) once every 23h 56m 4.09s Stars from the NCP to ( 90  - Obsr. Lat) are circumpolar e.g. in Syracuse, 43  lat stars from 90  to 47  declination are circumpolar Non-circumpolar northern stars are above the horizon from 12 to just under 24 hours. Lat of Obsr.

Looking East Stars rise all along the eastern horizon along paths that slant towards the south. The slant angle of rising stars relative to the vertical is equal to the observers latitude (i.e. 43  Stars complete one cycle around the sky once every 23h 56m 4.09s Stars near the celestial equator spend about 12 hours above the horizon.

Looking South Stars to appear to move along down-curving circular arcs from east to west (CW) Stars complete one cycle around the sky once every 23h 56m 4.09s Stars in the southern celestial hemisphere spend less than 12 hours above the horizon.

Fig. 1.4 This figure from the text, also summarizes the apparent motion. Remember that our goal is not to just describe the motion, but to quantify it by attaching relevant numerical quantities to the apparent motion of the stars.

The Five Rules for the Apparent Motion of the Stars 1. The altitude of Polaris equals the observers latitude and all stars rotate ccw around Polaris 2. The circumpolar region extends from Polaris down to a declination equal to (90 - obser. lat) 3. Stars rise along the eastern horizon at an slant angle toward the south from the vertical equal to the observer’s latitude. 4. Stars in the south move along downward curving arcs. The southernmost visible declination is (obser. lat – 90) 5. At mid-northern latitudes the time a star spends above the horizon is as follows: Northern stars > 12 hrs Stars near the celestial equator = 12 hrs Southern stars < 12 hrs