Planets
WHAT TO SEE
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PLANETS
The main planets that are clearly visible to a small telescope are Venus, Mars, Jupiter and Saturn. These appear in the sky to be very bright stars, but they move relative to the fixed background stars. How do you know you’re looking at a planet? Stars appear as pinpoints of light however much magnification you use, but the major planets have a definite size, appearing as small spheres through the telescope. Planets are best viewed with high-power eyepieces.
VENUS
Venus is the brightest object in the sky (apart from the moon and sun of course). It can be seen in the early evening or the early morning earning it the name morning/evening star. You can only see it at these times as, because it’s orbit is inside Earths, it can never be too far from the sun (it can never pass over the night-time side of Earth), only revealing itself after the sun has set or before it has risen.
It will rise up, reach it’s highest point in the sky, then dip down and pass across the sun then become the “morning star” then the same in the morning. Through the telescope it is dazzlingly bright, and not much actual detail can be seen on it as the planet is completely covered be cloud, but with a high-power eyepiece you can observe it’s changing phases, in the same manner as the moon.
MARS
Mars is the next planet in our solar system out from Earth. Mars can be seen as having a very deep-orange colour in the sky, like a bright star but not brilliant like Venus. It passed very close recently, and I was able to see it’s polar regions, a white icecap at the top with my Meade ETX-70.
Mars has seasons, much like Earth, meaning sometimes it’s South pole is facing us and sometimes the North pole. With a slightly larger telescope further details may be seen, such as dark patches which come and go on the planet’s surface.
JUPITER
Jupiter is the biggest planet in the solar system, so appears quite large through the telescope. It’s very bright, probably second only to Venus, so is quite easy to find. Through any telescope, four of it’s largest moons are visible, Io, Europa, Ganymede and Calisto.
Galileo discovered these as soon as he turned his newly-invented telescope to the planet. On higher powers on a very clear night through a small telescope, the cloud bands on the planet itself can be seen as well. The moons are in a different position every night, making it an interesting object to observe. On larger telescopes you can see the great red spot and also the shadow of the moons from time to time as they pass in front of the planet- this is called a transit, and they happen very frequently due to the fast orbital speed of the moons.
SATURN
Saturn appears as a yellowish, bright star, though not brilliant like Venus or Jupiter. And although Saturn is much further away than other planets, it’s good to observe because it’s very big, and because of it’s magnificent rings, and it’s these rings which make it unmissable for anyone with a telescope.
The rings are just visible at 40 x magnification, so should be within the range of most telescopes, through a slightly larger telescope on a very good night you may be able to see the division between the two rings, called the Cassini division.
The rings are actually hundreds of tiny rings made up of lumps of ice and rock. Galileo, on turning his telescope to the planet, concluded that it must have ears! It was not until much later that someone suggested the implausible notion that they were giant sets of rings around the planet. The angle that Saturn faces us at changes throughout it’s orbit, so when you see it once you may be looking straight down on the rings, and on another occasion looking at them on their side.
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