hk-planets
Hello,   tonight this stunning issue from Hong Kong Post. I really like these. Hope you do. Not aviation but close maybe !!  click image to enlarge for better view.
The issue is titled  “Astronomical Phenomena”.   Issued March 17th and showing seven astronomical phenomena to introduce us to the fascinating world of astronomy.
$1.70  Solar Eclipse
When the Moon moves between the Sun and Earth and blocks the Sun, a solar eclipse occurs. There are three types of solar eclipses: total solar eclipse, partial solar eclipse and annular solar eclipse. When a total solar eclipse occurs, in which the Sun is completely blocked by the Moon, the surrounding environment on the ground suddenly turns dark. This dramatic change is spectacular.
$2.20  Meteor Shower
When the Earth passes through the orbit of a comet, its meteoroids will enter the Earth’s atmosphere. Heated by the atmosphere, the meteoroids will become visible as meteors. A meteor shower is an event in which an unusually large number of meteors can be seen streaming from a certain point in the sky known as the “radiant”. Meteors from most meteor showers are fragments left over by comets in space.
$2.90  Comet
A comet is a celestial body that travels between the outer and the inner parts of the solar system. When it approaches the Sun, the temperature increases and, affected additionally by solar radiation and charged particles, the dust and rocks of the comet will be carried away or ionised, and separated from the comet’s surface. A comet normally shows two tails, one composed of dust and the other of ionised gas.
$3.10  Saturn’s Ring Tilt Variation
The tilting angle of Saturn’s ring does not change with respect to Saturn itself. However, if observed from the Earth, we will see that the tilting angle of Saturn’s ring appears to change. It is because the orbital period of the Earth is one year, while that of Saturn is about 30 years. When the Earth revolves once around the Sun, the relative position of Saturn also changes a little bit.
$3.70  Sunspot
Sunspots are small black spots on the surface of the Sun which are related to the magnetic activity of the Sun. A large group of sunspots may appear during a peak in solar activity. Sunspots are in fact not dark. They only appear dark as their brightness is lower than the normal surface of the Sun. Sunspots mostly concentrate around the solar equator and can last for hours or months.
$5  Moon-Planet Conjunction
The orbit of the Moon and the orbit of the Earth and other planets lie nearly in the same plane. So when we observe from the Earth, the Moon is sometimes seen to be very close to other planets. We call it a conjunction when the Moon and a planet are at an apparent closest approach. A Moon-planet conjunction may form an interesting pattern such as the “smiley face” in the stamp.
Interesting,  I hope you agree. Enjoy your stamps. Thanks to Hong Kong Post for the information. Well done.
Michael
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