Caption: Sky map of the winter night sky. Click on the image to get square pdf version for approximately the same date.

Features:

1. This how the night sky looks as seen from the Earth's equator on Feb04 at 9 pm standard time.

2. The horizon is the circumscribing circle.

3. The celestial equator bisects the sky.

4. The north celestial pole (NCP) is at the top and the south celestial pole (SCP) is at the bottom.

5. The equatorial coordinate right ascension (RA) increases going east along the celestial equator from its zero point vernal equinox. The vernal equinox is both the point where ecliptic crosses the celestial equator and also the event when the Sun traveling along the ecliptic crosses the celestial equator.

6. The vernal equinox happens on about Mar21.

7. Right ascension is given in the funny angle units of hours: 1 hour = 15°.

8. The equatorial coordinate declination (Dec) is measured from the celestial equator along great circles that pass through the north celestial pole (NCP) and south celestial pole (SCP).

9. Because we are on the equator, the celestial equator passes through zenith.

10. The ecliptic is the curve crossing the northern part of the sky map

    The ecliptic is the path of the Sun on the sky. It completes the path in one solar year.

11. The ecliptic coordinate system longitude is also measured from the vernal equinox going eastward, but in degrees.