Topic 5

• What is conjunction in astronomy?


  When two bodies, such as the Sun and Mercury, are in line when viewed from Earth.
• What is the difference between superior and inferior conjunction?

  Superior conjunction occurs when the planet is on the far side of the Sun, while inferior conjunction occurs when the planet is between us and the Sun.
• What is the ecliptic?


  An imaginary plane linking the Sun and the Earth.
• How does the Sun appear to move in relation to the ecliptic throughout the year?

  The Sun appears to follow the ecliptic line through the sky throughout the year.
• What is elongation in astronomy?

  The angular distance from an inferior planet to the Sun.
• What is the first point of Aries?

  The point where the ecliptic crosses the equator in spring, marking the vernal equinox.
• When does the first point of Aries occur?

  On the 21st of March.
• What is the first point of Libra?

  The point where the ecliptic crosses the equator in autumn, marking the autumnal equinox.
• What is an inferior planet?

  A planet with an orbit closer to the Sun than Earth.
• What is occultation in astronomy?


  When one celestial body completely covers another celestial body, such as the Moon passing in front of a star.
• What is opposition in astronomy?


  When two bodies, such as Venus and Mars, are on exactly opposite sides of Earth.
• What is a radiant in the context of meteor showers?

  The point in the sky where a meteor shower appears to originate.
• What causes retrograde motion of a planet?

  It is caused by the relative motion between Earth and the planet as we overtake it in our orbit.
• What is a superior planet?

  A planet with an orbit further from the Sun than Earth.
• What is a transit in astronomy?


  When a planet passes in front of another celestial body, such as the Sun, but does not completely cover it.
• What is the zodiacal band?

  A band around the ecliptic that all planets travel within, as the Sun appears to pass through the 13 zodiac constellations throughout the year.
• Why is it unsafe to directly observe the Sun with the naked eye?

  Because the retina does not produce pain signals, leading to potential damage without immediate awareness.
• What is the safest method to observe the Sun?

  By projecting its image onto paper or card.
• How can you project the Sun's image using a card?

  By putting a small hole in the card and projecting the light onto paper.
• What precautions should be taken when observing the Sun using projection methods?

  Never leave the setup unattended due to the Sun's heat potentially combusting materials.
• What are some tools mentioned for projecting the Sun's image?

  Sunspotter and Solarscope.
• What is the risk associated with using telescopes with special solar filters?

  The Sun can crack these tools if not used carefully.
• What does telescopic projection involve?

  Pointing the telescope at the Sun and using the eyepiece to project the image onto a surface.
• What should not be used when performing telescopic projection?

  The finding scope on the side, as the Sun's heat can melt the cross-hairs.
• What is H-alpha in the context of solar observation?

  It is a specific wavelength in the visible red part of the spectrum.
• How do optical H-alpha filters assist astronomers?

  They allow astronomers to study the Sun's surface by focusing on a narrow bandwidth.
• What is a pinhole camera used for in solar observation?

  To project sunlight through a small hole onto a smooth surface.
• When is using a pinhole camera especially useful?

  During a transit or partial solar eclipse.
• What household item is mentioned as a good tool for making a pinhole camera?

  A kitchen colander.
• What are the steps to safely observe the Sun using projection methods?

  • Use a card with a small hole to project sunlight onto paper.
  • Ensure the setup is attended to avoid combustion.
  • Consider using tools like Sunspotter or Solarscope.
  • Use telescopes with special solar filters carefully.
• What are the different methods of observing the Sun mentioned in the material?

  1. Telescopic Projection
  2. H-alpha Filter
  3. Pinhole Camera
• What are comets primarily composed of?

  Ice and rock bodies
• What happens to a comet as it approaches the sun?

  Some water-ice evaporates, creating a spherical coma around the nucleus
• How does the coma of a comet compare to its nucleus?

  The coma may be many times larger than the nucleus but is very thin
• What forms when a comet gets nearer to the sun?

  A tail forms in the opposite direction to the Sun
• How many tails does a comet have when it approaches the sun?

  Two tails
• What causes the curved dust tail of a comet to form?

  Radiation pressure from the Sun
• How long can the dust tail of a comet be?

  Up to several millions of kilometres long
• Why is the dust tail of a comet bright to an observer?

  Because of the reflection of the ice particles from the Sun
• What produces the ion tail of a comet?

  Particles from the solar wind hitting the comet