Conjunction of Jupiter and Venus – Photos

•March 11, 2012 • 1 Comment

Last month, I was in Pulau Perhentian, Malaysia when the Moon met Venus and Jupiter. The sky was clear, so we had a good view of the trio. It’s still not too late to enjoy the scene, see my previous post for more info.

In the meantime, enjoy the photos…

The next day, the Moon moved between Venus and Jupiter…

Click here for bigger version of the photos.

Conjunction of Jupiter and Venus

•February 23, 2012 • 1 Comment

This is going to be good.

From today onwards until end of March, every evening, after you have finished your dinner, go outside and look west. A beautiful sight awaits.

There, in the twilight, the brightest planets in the sky – Jupiter and Venus – shine brightly. Higher up is Jupiter and nearer to the horizon is Venus.

Go out again the same time tomorrow, the view will be better. Jupiter and Venus are slightly nearer now. In mid-February, they are about 20 degrees apart. By end of the month, their separation shrinks to 10 degrees. They will continue to converge until mid-March, when their separation is at minimum – only 3 degrees apart.

Jupiter and Venus converging from Feb 23 to Mar 27, 2012. Star chart for Kuala Lumpur (~3N, ~101E), 8:30 pm. Star chart generated from Stellarium.

 

Pay special attention to the evenings of Feb 25-27 and Mar 25-27, when a crescent moon will join the duo. You do not want to miss them.

Conjunction of Jupiter, Venus and the Moon. Kuala Lumpur Sky, Feb 26 (top) and Mar 26 (bottom), 8:30 pm

Don’t worry if you are living in a city with light pollutions or if the weather is not excellent. The Moon, Venus and Jupiter are the three brightest objects in the night sky; together they can shine though streetlights, and even some thin clouds.

Not always do we have so many bright objects group together in such a small area of the sky. So, if they weather is good, then head out and take a look. Trust me, you will be mesmerised.

~~~~~

Always look up, and you will be rewarded with the beauty of the night sky…

New Horizon Spacecraft may be on a Stamp, with your help

•February 6, 2012 • Leave a Comment

You can help to put a spacecraft on a US postage stamp.

The mission team for NASA New Horizon spacecraft, the first spacecraft in human history that will visit Pluto, had come up with the idea of putting the spacecraft on a stamp to commemorate the encounter:

New Horizon left Earth in January 2006, and will reach Pluto in July 2015. New Horizon is the fastest spacecraft ever launched, but it still takes more than 9 years to reach its destination.

According to their news release, “You can help make this happen,” says New Horizons Principal Investigator Alan Stern. “We’re asking people to sign the petition, because the post office considers not just the merits of a new stamp proposal, but also whether it is supported by a significant number of people.” They are starting the process now because it can take three years or longer for a postage stamp proposal to result in an actual stamp, hopefully will coincide with the encounter.

Pluto had made it into a stamp before, in 1990, labelled “Not Yet Explored”. Now New Horizon is on the way to explore it, so I think this stamp serve as an update to its status.

I had signed the petition, if you think you like it, then sign it. I’m not sure how we can get the stamp here (if it really do made into an actual stamp), but I think it’s cool to have a spacecraft on a stamp.

You don’t see it, but it’s there

•January 24, 2012 • Leave a Comment

Dione and Mimas by Cassini. Credit: NASA/JPL-Caltech/Space Science Institute

The bigger moon that filled the view is one of Saturn’s many moons Dione. The night side of Dione blended into the dark space beyond and it seems like there is nothing there. But with the help of the smaller moon Mimas peeking out from behind, we can see the edge of Dione, and realised that there is something there after all.

Let’s Look for Comet Lovejoy Now!

•December 24, 2011 • Leave a Comment

You have to wake up early for this.

Comet Lovejoy. Credit: Colin Legg

Comet Lovejoy has now brightened to naked eye visibility. It can be seen in the morning twilight just before the Sun rises in the constellation Scorpius. You need a clear and unobstructed eastern horizon to increase your chances to see it. If the weather condition is good, even if you can’t see the comet head because of foreground obstruction, you might still be able to glimpse the comet tail.

Comet Lovejoy rising over Western Australia by Colin Legg

The sighting of Comet Lovejoy favours the Southern Hemisphere. Theoretically, we at the equator might be able to see it, but we really need a clear horizon. The visibility of the comet could improve in the days ahead as the comet moves away from the Sun and the background sky darkens accordingly.

Below is a very very stunning image of Comet Lovejoy – a view from space!! This jaw-dropping image of Comet Lovejoy was taken by Dan Burbank, the Expedition 30 commander onboard the International Space Station.

They even created a time lapse video of it!

 

These fantastic images of the comet are only part of the story. Let’s talk a bit on the story before this…

Comet Lovejoy, which bears the official name of C/2011 W3, was discovered by an amateur astronomer Terry Lovejoy early December. This comet is a sungrazer – a comet that passes extremely close to the Sun. The most famous sungrazers are the Kreutz Sungrazers, which all originate from one giant comet that broke up into many smaller comets during its first passage through the inner solar system. Comet Lovejoy belongs to these Kreutz family comets, so did the Great Comets of 1843 and 1882, and Comet Ikeya-Seki in 1965. They were all fragments of the original comet.

Because Kreutz sungrazers are typically small (~10 metres wide), they usually will be completely evaporated during a close approach to the Sun. However, larger ones may survive their passage through the Sun. And Comet Lovejoy is one of those larger one. On Dec 16, Comet Lovejoy plunged through the Sun atmosphere and emerged from the other side intact (the video below is a must see). It was a surprise for the scientists, because they thought that its icy core was not large enough to survive the passage.

Credit: NASA/SDO

After surviving the journey, Comet Lovejoy is now moving away from the Sun and going back to the frozen deep space. As it is backing out, it does not forget to put on a show for us, as can be seen from the picture at the beginning of this post.

I got a place near my house with a unobstructed eastern horizon. I’m going to give the Comet a try (in few hours’ time, actually). Wish me clear sky!

Photos of Total Lunar Eclipse – 10 Dec 2011

•December 14, 2011 • 1 Comment

The total lunar eclipse last Saturday was great! The weather cooperated – the sky was partially cloudy, but the clouds were mostly at not where the Moon was. Although occasionally the clouds hide the Moon, overall I still managed to get most of the eclipse progress.

This is my best shot of the night and I like it very much. This image shows 3 things: (1) part of the Moon not in shadow (bright part at the lower right), (2) turquoise colour edge and (3) the reddish Earth’s shadow (see diagram below for illustration).

The turquoise colour in the previous image I took in Jun was not that obvious and this time I was hoping to get a more definite turquoise colour and I’m happy that it turned up nicely in the image. As was explained in my previous post, the turquoise blue colour comes from light passing through the ozone layer, which absorbs red light and makes the passing light bluer. This can be seen as a soft blue fringe around the red core of Earth’s shadow.

 

I had combined all the photos into a short video. Enjoy!

 

This is how the sky looked like at the beginning of the eclipse. Luckily the clouds were moving and it was clear after that.

Credit: all photos by thchieh

Total Lunar Eclipse – 10 Dec 2011

•December 8, 2011 • 2 Comments

Imagine you are outside your house breathing some fresh air and enjoying the night view around you. You look up at the sky, hoping to catch a star or two, but what you saw instead was a reddish orangey full moon hanging in the sky. What happen to our Moon?!?

No fear, there is nothing wrong with our Moon – our Moon is as normal as it always is. It’s just passing through the Earth’s shadow, and we call that a lunar eclipse.

This is going to happen on Saturday (Dec 10), on a convenient time for us (in Malaysia). The Moon starts to enter the penumbral shadow at 7:33 pm and exit by 1:30 am the next day, with maximum eclipse at around 10:30 pm. This means that we no need to stay up late into the night to see it.

Credit: F. Espenak, NASA’s GSFC

For animation, click here. As you can see from the animation, as the Moon enters the Earth’s penumbra (P1 to U1), you may not observe any changes. The show really starts after 8:45 pm (U1), when the Moon starts to enter the umbra shadow. Look for the colour change (to reddish) as the Moon moves deeper and deeper into the shadow. Between 10:06 pm (U2) to 10:57 pm (U3) is what we called totality – this is the time when the whole Moon is in Earth’s umbra. After that, the Moon will slowly come out from the shadow, and by 1:30 am, you can pack and go to sleep.

Total Lunar Eclipse of 16 Jun 2011 taken outside my house. I did not managed to finish the whole sequence because the clouds rolled in. Credit: thChieh.

 

Why does the Moon turns reddish or orangey during totality? Shouldn’t it disappear as it enters the Earth’s shadow? The reason is our atmosphere. Take a look at the diagram below and it’ll explain everything.

If the Earth had no atmosphere, the Moon would be completely dark during an eclipse. The presence of Earth’s atmosphere means that sunlight reaching the Moon must pass through a long and dense layer of air, where the light is scattered. Shorter wavelengths (blue) are more likely to be scattered, so by the time the light has passed through the atmosphere, the longer wavelengths (red) dominate. The scattering depends on the conditions/particles in our atmosphere, which in turns determine the colour of the totality Moon. Anything from bright orange to blood red is possible. If there has been a major volcanic eruption, for example, the atmosphere has so much dust that the shadow on the moon will appear dark throughout an eclipse.

What colour are we going to see this Saturday? It will be a surprise…

(When the eclipsed Moon is bright, the stratosphere is clear. On the other hand, a dark eclipse indicates a dusty stratosphere. There are atmospheric scientists out there who are studying lunar eclipses as a means of monitoring conditions in Earth’s upper atmosphere. How cool is that?)

 

But don’t just look at the red. A more not known colour is the turquoise blue. I’m not sure if it is visible to the naked eye, but I’m sure if you take a picture of it, you will see it (see picture below). This comes from light passing through the ozone layer, which absorbs red light and makes the passing light bluer. This can be seen as a soft blue fringe around the red core of Earth’s shadow. Start looking for the turquoise colour as the umbra eclipse begins (U1), it will be more obvious as the Moon moves into shadow, or when starts to come out of the shadow.

Total Lunar Eclipse of 16 Jun 2011 taken outside my house. The Moon had just fully entered the unbral shadow (U2). The top part is darker because it was deeper in the shadow; the bottom part is bluish due to the reason described above. Credit: thChieh.

If you are in an area without much light pollution, you can actually see the stars around the Moon during totality. Usually the bright full moon will drown all the stars around it, but during a totality, you can take picture of the full moon with the stars.

Go out and take a look at the Moon after dinner this Saturday, you won’t want to miss it, because this will be the last total eclipse until year 2014. Yes, you read it right. There will not be any total lunar eclipse for two whole years. So grab this last opportunity!

 
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