Autumn Night Sky in Crete

Stars and Constellations in the autumn night sky of Crete

Now that the summer months in Crete are gone, we move to other constellations in the Autumn night sky of September and October. The close area around alpha Capricornus is a good test field for the naked eye. In a field of 2° you can spot 5 stars between magnitude 3.5 and 6.9.

Take a look and see how good your eyes are, you will need a dark sky to spot the weakest star. We leave the Milky Way behind us and we go beyond our own galaxy. The first constellation we encounter is Capricornus, meaning the sea goat (sea-goat or goat-fish is a wondrus creature invented by the Babylonians. Sea-Goat is also mentioned in a Greek myth: When the goat-god Pan was attacked by the monster Typhon, he dived into the Nile; the parts above the water remained a goat, but those under the water transformed into a fish).

Capricornus is one of the zodiac constellations; this means that the path of the sun and planets runs thtough the zodiac constellation. Capricornus (term used by Astronomers) means a horned goat in Latin, and in Astrology it is known as Capricorn.

Detail chart of the area round Algedi the alpha star in Capricornus. When you look real good at Algedi you will notice a second star. It’s only 380” separated from Algedi. Try to see them both with the unaided eye.

As we move more to the east we find the constellation Aquarius, meaning water carrier. Aquarius covers a very big area, and is also a zodiac constellation. The brightest star is alpha Aquarius, named Sadalmelik. The star is 1100 light years away from us and 600 times brighter then our sun.

When you look at the chart to the west from alpha Sadalmelik, you will find the M2. More than a century and a half passed before astronomers realized that globulars are in fact collections of several hundred thousand extremely old stars. No we know that the M2 is a globular cluster. With the unaided eye is this impressive cluster like a weak star out of focus. Don’t forget that you are looking 40000 light years away.

As I already told you, constellations in the zodiac area can harbour planets. During the autumn it’s Uranus that travels through the water carrier. Uranus is the 8th planet from the sun. It takes 84 years to move around the sun.

One Uranus day is 17 hours an 15 minutes and the temperatures are -215°. The average distance to the sun is 2.88 milliard km. The angle of the planet axis is 98°, what means that there are almost no season. Like Saturn, Uranus has also rings. Those rings are extremely weak and only visible with very big telescopes.

What can you aspect to see with the naked eye? The planet will be a faint star between others, so it will be necessary to observe it for a longer time. Then only, you will be sure that you saw Uranus because Uranus moves against a background off stars.

The people with binoculars have a big advantage; they will spot the movement earlier. To see a planet disk you need at least a 15 cm telescope. This detailed chart will help you locate Uranus.

What can be better than after the water carrier we meet the fishes. This constellation by name Pisces is located to the east of Aquarius. The constellation Pisces is difficult to locate, because there are no bright stars. It will become more interesting when there are planets moving through.

You will have to wait till next year for Uranus to move in Pices. A special occasion will be that on 20 September 2010 both planets Uranus and Jupiter will be close together in the south west of the constellation.

The big square Pegasus “the flying horse” hovers above the constellations Pisces and Aquarius. I use this constellation to navigate between the other star patterns. Because of the 4 bright stars on each corner is it easy to find.

Pegasus harbours many beautiful deep sky features but for that you need a telescope. There’s one globular cluster in reach of binoculars, the M15. This gathering of a million stars swirls with a distance of about 42000 light years from us.

About 5° to the west of Enif (epsilon pegasi) you will see in binoculars a misty patch with a little brighter core. The size of the M15 in telescopes is 12’ to 18’, the field is filed with countless stars.

When we keep flying with the horse of Pegasus to the North West we encounter 4 beautiful small constellations. Equuleus, Delphinus, Sagitta and vulpecula. This means in the same order, the Colt, the Dolphin, the Arrow and the Fox.The last 3 constellations are settled in the Milky Way. This makes it difficult to locate them because of the rich starry background.

Equuleus, Delphinus, Sagitta and vulpecula

To the naked eye there’s only the constellation Vulpecula that shows you something of interest.The Cr 399 or the Coat hanger is a distinctive star pattern. Its diameter is twice the apparent size of the full moon. Take your time to collect the light of those stars. And you will see the shape of the coat hanger. With binoculars is the shape easy to spot.

For people with binoculars there’s is a nice deepsky object to see. The M27 is a bright and big planetary nebula. You will see a grey puff of light in the shape of an oval.

The picture of the M27 gives you an idea how the planetary nebula looks like in the 500 mm dobson telescope at Sasteria observatory.

A planetary nebula forms when a star can no longer support itself by fusion reactions in its centre. The gravity from the material in the outer part of the star takes its inevitable toll on the structure of the star, and forces the inner parts to condense and heat up. The high temperature central regions drive the outer half of the star away in a brisk stellar wind, lasting a few thousand years.

When the process is complete, the remaining core remnant is uncovered and heats the now distant gases and causes them to glow.

In the constellation Delphinus you find the star Gamma Delphini. This very pretty double star is easy to split and presents a gold primary and a pretty blue secondary. One of the finest double stars in the sky, it is located at the tip of the “nose” of the dolphin. Check it out with binoculars!

There will be full moon on the 15 September and the 14 of October. On the evening of 9 September 2008, there will be a bright star occultation by the moon.

The hour is about 21h 50’ 48” UT. This means you have to at 2 hours for the east location. So look up from 23h 45’ LT so you can see the star closing in to the dark side of the moon. The star reappears about 00.55 LT (local time).

Jupiter and Mars are now very low in the western evening sky as a bright star after the sunset. Venus is a very bright star after sunset; the planet closes in with Mars on September 11. The best time to see Mercury is on September 10 also after sunset.

Mercury reaches greatest elongation in the morning of October 22. That means that you can spot the planet the last 3 weeks of October before sunrise. Because Venus and Mercury are planets moving between the earth and sun, you can only observe them close to the sun in the evening or in the morning.

Venus and Earth are nearly the same size. Venus and Mercury can show just like the moon different phases, because they are inside planets. Uranus will be visible the whole night, and reaches opposition on September 12.

See the constellation Aquarius for a finders chart. Opposition means, the planet Uranus and the Earth and the Sun are in a straight line with each other. This is always the best moment to observe the planet, Uranus stands high in the night sky and the sun is on the other side of the Earth. Saturn is again visible in the early morning before sunrise. You will find the planet in the constellation Leo after September 20. More details on the winter guide.

I wish you much pleasure in watching the autumn night sky.

Greetings,
Feys Filip.