Systematic introduction to the Lénárt sphere

• Components: Ruler, Protractor, Compass
• Practice with Ruler and Compass: Two points, straight line. Third point, straight line to one of the first two. Measure the angle.
• Measure two of the line segments with the ruler. Same unit for angles and lengths!
• Establish: North Celestial Pole, Celestial Equator
• Draw Ecliptic
• Mark ♈ (conventional symbol for the First Point of Aries) at the Spring (Vernal) Equinox
• Identify Summer Solstice, Winter Solstice, Fall (Autumnal) Equinox
• 60° along the Ecliptic from the First Point of Aries, draw a star.
• What is its RA? What is its DEC?
• Convert RA in degrees to hours minutes and seconds (sexagesimal system)
• Identify Deep Springs at 37° latitude
• Draw the horizon visible from this point.
• Find 0°, 90°, 180°, and 270° of azimuth along the horizon. Mark these N, E, S, and W.
• What are the Alt-Az coordinates of the star. It may be below the horizon, in which case its altitude is negative.
• Make a triangle whose angles are 90°, 90° and 72°. Measure the lengths of its sides.