Sidewalk Astronomy at Yew Tee

Last Friday (7th February 2014), Scobbers Alfred, Everlyne and Kin Guan showed the wonders of the night sky to the public in Yew Tee for the first time this year. This was a collaboration between Science Centre Singapore and Yew Tee RC Zone 10.

We brought our C8 Celestron telescope out and set the venue up with the help of RC volunteers. The venue was Yew Tee MRT Open Space (In between Yew Tee Square and Yew Tee Mall). (Google Street View)

Cloudy weather around 7pm on Friday. What could we see?

Scobbers having a briefing with RC volunteers.

Setting up the banner. 

We started the telescope viewing at 8pm and the queue was already forming:

Thanks to the clear sky (the clouds kindly made way for us), we were able to observe first quarter Moon (it's a half-lit moon from Earth's perspective) and Jupiter. Alfred manned the telescope and introduced some fun facts about Jupiter and Moon:

Everlyne interacted with the public in the queue and handed them Star Map. It is a handy tool to identify the objects in the night sky!

Happy Belated Mid Autumn Festival!

Scobbers were so busy that we forgot that Mid Autumn Festival has past! Other than filling ourselves with mooncakes and playing with sparklers, we found out some amazing facts about the Moon that you might not know.

1. The Moon was created in a huge impact event by a Mars-like object

Artist's Impression of Giant Impact event (Source: Wikipedia)

Termed as "Giant Impact Hypothesis", most scientists think that the Moon was formed after a great collision between the Earth and a Mars-sized object 4.5 billion years ago. It explains why the Earth and the Moon spin in similar ways. Scientists also did some calculations to show that if the post-impact Earth revolves in a 2-hour period, i.e. a day is 2 hours instead of 24 hours, we can explain some of the observations.

After the direct impact, the cores of the Mars-sized object and the young Earth fused. The collision made the post-impact Earth spin so fast that a significant portion of the Earth's mass was ejected to form the Moon. By the conservation of angular momentum (a quantity to describe an object's rotation), the Earth-Moon system has similar spin directions.

Also, if the Moon was created from the Earth's material we can explain the fact that the Earth and the Moon have similar chemical compositions. For example the isotopes of oxygen and titanium were found to have identical ratios in both lunar and terrestrial rocks.

The Mars-like object is commonly known as Theia. In Greek myth, Theia is a titan who gave birth to Selene the Moon, Helios the Sun and Eos the Dawn. That's why we use Selen- (or lunar) and Helio- to describe stuff related to the Moon and the Sun respectively.

2. We are always looking at the same side of the Moon

Near side of the Moon (Source: Wikipedia)

Far side of the Moon (Source: Wikipedia)

Readers may have known this fact a long time ago. The "dark" side of the Moon has also been depicted in movie as well. Of course, there are neither giant robots nor military bases located at the far side of the Moon, as shown in the NASA Astronomy Picture of the Day on 16 September 2013. (Direct YouTube link)

There is nothing hidden behind the Moon as shown in photos taken by lunar probes. There are only craters at the far side of the Moon (the side that is not facing us). On the other hand, the near side of the Moon (the side that is facing us) has more interesting features. Apart from the craters there are valleys, mountains and maria (meaning Sea in Latin). Maria appear dark as they mainly contain iron compounds that are less reflective. People in ancient times made up stories for the observed patterns, such as the Moon rabbit legend in Chinese culture. Do you see it in the following picture?

Did you see the Moon Rabbit? (Source: Wikipedia)

Regarding why the Moon always faces with the same side, we need to know how gravity works. Every massive object in the universe attracts each other with a force called gravity. For instance, an apple drops to the ground due to the Earth's gravity (the apple also attracts the Earth, but the effect is very negligible due to the Earth's much larger mass). The strength of the gravity depends on the distance between two objects, so in this case the near side is more attracted than the far side is, making the Moon face towards the Earth with only one side. This effect is called "Tidal Locking".

3. One day, we will lose the Moon

The Moon exerts a gravitational force on the Earth (and vice versa), pulling the water nearer to itself and causing high tide on the Earth. As the Earth rotates underneath the water (we can imagine Earth being a solid rocky ball covered by water), it tugs the tides and loses some of the rotational energy. As a result, the Moon picks up some of the energy and then speeds up, ascending from its orbit. On average, the distance between the Earth and the Moon increases by around 4 cm every year.

It has an interesting side effect: as the Earth loses rotational energy it will rotate slower and slower. The length of a day will increase as a result, amounting to 2 millisecond per century. Wish to have 48 hours per day? Perhaps if you're still around after 4 billion years!

Reference:

1. Wikipedia. Moon. Retrieved 20 September 2013, from http://en.wikipedia.org/wiki/Moon
2. Geology 5835 - The Moon - Fall 2006. University of Colorado Boulder. Retrieved 20 September 2013, from http://lasp.colorado.edu/life/GEOL5835/Moon_presentation_19Sept.pdf
3. A New Model for the Origin of the Moon. Harvard University. Retrieved 24 September 2013, from http://www.fas.harvard.edu/~planets/sstewart/Moon.html
4. M. Ćuk, S.T. Stewart (2012). Making the Moon from a Fast-Spinning Earth: A Giant Impact Followed by Resonant Despinning. Science Vol. 338 no. 6110 pp. 1047-1052.

June 2013 - Venus, Mercury, Solstice, Supermoon and HAZE!!!

June got off to a pretty good start with clear nights and some great views of Saturn.

Planets Venus and Mercury also made an appearance shortly after sunset. Mercury was at its highest on 12th June, about 24 degrees high at sunset. Its gradually getting lower each day before disappearing by end June.

I took this picture on 10th June, when a thin waxing crescent Moon was near Venus. Mercury is the dimmer object above Venus near the top edge of the photo.

Venus will get higher each day from now until November as it makes its way closer to Earth.

Mercury-Venus Conjunction
On 20th and 21st June, Venus and Mercury will appear close together (about 2deg apart). Due to their low position in the western part of the sky, they will only be visible from 7:30pm-8pm.

Screenshot from Stellarium planetarium programme - posted on Singapore-Sky Facebook page by Dr KK Cheong.

Sadly, the haze that has currently enveloped the island will make these planets almost impossible to see.

Northern Solstice
June 21st is the time when the Sun reaches its northernmost point in the sky due to the tilt of the Earth. This also causes warmer temperatures and longer daylight hours in the Northern parts of the world.

In Singapore, expect the Sun to rise from the north east and set in the north west. Daytime will also be slightly longer than usual, 12 hours 11 mins 43 secs to be more exact. Sunrise: 7:00am, Sunset: 7:12pm.
For more info on Solstice see last year's post: Solstice in Singapore

Supermoon Returns
23rd June 2013 is Full Moon in Singapore. Its also the Moon's closest perigee (the Moon's closest point to Earth), resulting in a  larger than normal Full Moon, known as a Supermoon.
Even at its closest point the Moon is still 356989km away, therefore the difference in size is hard to notice.

Size difference of Full Moons at closest position to Earth (perigee) and furtherest distance (apogee)

Usually the Moon looks bigger when its lower in the sky due to an illusion where are brain perceives objects near the ground closer than those high in the sky.
The June Supermoon is actually closer than other supermoons that occur in the year but once again it will be difficult to notice unless you compare photos of other full moons.
More on supermoon: Earth and Sky - Most "Super" Supermoon

Haze
These three astronomical events are quite subtle and can be missed if you don't know what you're looking for. Visibility is made worse by the haze blowing over Singapore from Sumatra.
The air quality/Pollutant Standards Index is currently in the unhealthy-hazardous range, so its not the best time to be going outside looking at the sky.
Took a picture of the hazy Sun setting behind Science Centre on the way home last night.

Someone commented that it looked a bit like Lord of the Rings, i.e. the eye of Sauron above the Dark Tower Barad-dur. A few minutes later I saw a post from SGAG with the exact same idea:

Original picture submitted by Jonathan Chong. Posted on SGAG facebook and www.sgag.sg

What's up for April 2013

Stars and Constellations

For the past few months we've been focused on the bright stars and constellations of Orion, Taurus, Canis Major, Gemini, etc. During the early evenings of April, these stars are getting lower and lower  towards the West each day.

The bright reflected light of Jupiter is still visible in this part of the sky close to Taurus. By next month most of these stars will begin to disappear from view.

From April onwards, we start to shift our attention to the bright stars of the South, including the second brightest star in the night sky, Canopus, part of the constellation Carina. Canopus was also known in China as “Old Man of the South” for its southern location and sometimes red appearance in hazy or cloudy conditions.

The constellations Puppis, Vela and Carina form the ancient star pattern of the Argo Navis, representing the sailing ship from an Ancient Greek legend. 

The asterism (star pattern) the False Cross is sometimes confused for the Southern Cross (Crux), located nearby to the east.

Lying close to a dense part of our Galaxy, The Milky Way, several star clusters can be found when scanning the  area with binoculars.

1) & 2) M46, M47 – Two faint open clusters, east of bright star Sirius. M47 is the closer and brighter of the two. Small telescopes maybe required.

3) M93 – Faint wedge-shaped star cluster over 3000 light years away but visible in binoculars.

4) IC2391 – large open cluster of 50 stars surrounding the star Omicron Velorum. Best viewed using binoculars.

5), 6) ; 7) IC2581, NGC3293  NGC3114   Three fainter open star clusters located in front of the rich spiral arm of the Milky Way. Binoculars and small telescopes required.

8) Eta Carinae Nebula (NGC 3372) – a gas cloud surrounding the explosive variable star Eta Carinae. Several more stars are visible through binoculars and telescopes.

9) NGC3532 -  A large bright open cluster containing more than 100 stars forming an elliptical shape, 1300 lightyears away.

10) IC2602 (The Southern Pleiades)  Large open cluster of around 60 stars surround star Theta Carinae. Easy to spot with binoculars .

Saturn

Every year planet Saturn makes it appearance in the sky when it approaches opposition, i.e. when the Earth moves into alignment with both Saturn and the Sun. This period results in the closest distance between Saturn and Earth and the brightest and biggest view of Saturn in the sky.

Opposition occurs on 28th April 2013. So can we can expect to be observing Saturn at SCOB during the later part of the month.

Moon

Here are the dates for the main moon phases this month. We will be observing the Moon at our Friday night stargazing sessions on Friday 19th April and Friday 26th April.

Full Moon on 25th/26th April 2013 will result in a Partial Lunar Eclipse over Singapore, when the Moon enters the outer edge of Earth's shadow (the penumbra). However, this is only a very small eclipse, therefore the Moon will only darken slightly during 2am-6am on Friday 26th April, (Singapore time).

We will not be holding any eclipse viewing event at SCOB.

It may be difficult to notice any change in the moon's brightness.

Lyrids Meteor Shower

Finally, 21st/22nd April is the annual Lyrids Meteor Shower, one of the brightest showers of the year. We will not be organising any meteor shower events because most meteors cannot be seen in a bright urban environment like Singapore.

You can increase you chance of seeing a few meteors by going to a wide open area such as a sports field, beach or reservoir, but the frequency of meteors may only be about one or two per hour.

Meteor showers are best observed from midnight til dawn. Lyrid meteors originate from the north-east direction but can appear in any part of the sky.

First week of March 2013

Last Friday 1st March, the sky cleared for our first stargazing session of the month.
At first it was mostly cloudy with lightning in the distance so we delayed our start time to allow the weather to improve. Whilst waiting we had time to watch the dramatic sunset.

Sunset 1st March 2013 - Science Centre Singapore Observatory.

After 8pm the sky was clear. As usual, Jupiter was the main target for most of the first hour. Just like the previous week, the Great Red Spot (a giant storm) was faintly visible amidst one of the equatorial cloud belts.

Jupiter - Taken on 22nd Feb 2013 - from Science centre Singapore, through a 16 inch Cassegrain using a Nikon D70s. The great red spot is just visble on the left, beside the southern equatorial belt (lower dark band).

Jupiter - taken on 22nd Feb 2013 - through a 6 inch refractor. Sidewise orientation due to position of Jupiter in the sky (towards the west) and the position of the camera.

Later in the evening we turned are attention to the bright stars and constellations of Taurus, Orion and Canis Major. The great Orion Nebula (M42) was particularly stunning in the main 16-inch telescope, especially as there was no moonlight around.

After closing time, a few of us stayed back to take some photos of constellations:

Orion (top) and Jupiter (brightest, below) next to bright star of Aldebaran (in Taurus) - taken facing west - 1st March 2013.

Rectangular constellation of Gemini - bright stars Pollux (on top) and Castor (below). Facing North.

Close up of Orion

Close up of Canis Major - brightest star Sirius (top right).

Canis Major & Sirius (top right) with Carina & Canopus (below) - facing South

Waning Gibbous Moon rising from the East - 1st Mar 2013 10:45pm

Back at home, on Sunday evening (3rd Mar) there was was a bright flyby of the International Space Station (ISS) over Singapore. It would have made a nice photo as the ISS passed  right next to Jupiter and through Orion. However, 10 minutes before the flyby, a big patch of cloud blocked that part of thesky. ISS was visible for a few seconds through gaps in the clouds but all I got on camera was a faint streak as it approached Jupiter:

Faint trail of ISS passing by Jupiter on a cloudy night - 3rd March 2013 - Singapore 

Finally, the Moon is currently going through its waning phases as it moves around the morning side of the Earth. I've seen it every morning this week as I walked to the MRT to get to work. Every day getting closer and closer to the Sun as it approaches New Moon, resulting in its phase changing from a Large bright Gibbous to a half and then just this morning a thin crescent Moon.

Waning Gibbous Moon - 28th Feb 2013 - 7:30am - Singapore

Last Quarter Half Moon - 4th March 2013 - 7:40am - Singapore

Waning Crescent Moon - 7th March 2013 - 7:45am - Singapore

New Moon occurs on Monday 11th of March, which means it will not be visible this weekend as it will be too close to the Sun to see. By the end of next week it will return to the evening sky as a crescent Moon around 13th-15th March.

To see the Moon at SCOB this month I would recommend either Friday 15th March or Friday 22nd March.
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Also we've seen no sign of Comet PANSTARRS C/2011 L4, which is at its brightest this week. However, its extremely low in the sky between 7pm and 7:30pm, almost exactly west after sunset. So far, its been cloudy every day in that direction so it will be challenging to spot it.

February 2013

ISS
February starts with a bright International Space Station (ISS) pass over Singapore on Sun 3rd Feb 7:38pm-7:45pm.

During this time the ISS will pass almost directly overhead, from south-west to north-east between the bright stars of Orion and the planet Jupiter.
The only things that will interfere with its visibility will be clouds or the bright evening sky at this time of year.

Star map showing the path and timings of ISS pass on 3rd Feb in Singapore.

Sunrise-Sunset
You may have noticed that mornings remain darker for longer and early evening (ard 7pm) is brighter than usual.
Every year in February, Earth is halfway between its Solstice(21st Dec) and Equinox(21st Mar) position, resulting in the latest sunrise and sunset of the year in equatorial regions like Singapore.
Around 10th Feb the Sun rises at 7:17am and sets at 7:21pm.
Therefore the late sunset may impede ISS visibility.

Chinese New Year!
Its no coincidence that CNY also occurs on 10th Feb this year.
The date of Chinese Lunar New Year is also related to the position of the Sun at this time of year.
In China, the Sun's position around 3rd-4th Feb traditionally signifies the start of spring or Lichun 立春.
The New Moon closest to Lichun, is the start of the lunar new year.

Moon dates for Feb 2013

Obviously, during new moon, the moon is facing towards the Sun and is obscured from view. You can expect to see the Moon in the evening from 14th Feb to 26th Feb.

Position of the Moon in the early evening sky during Feb 2013

Jupiter's Moon
Jupiter remains the brightest planet in the night sky. During Friday's at SCOB we'll be able to see the following arrangement of its four biggest moons:

Mercury
The closest planet to the Sun, reaches its maximum elongation (18deg) east  of the Sun, meaning Mercury is at is highest position, towards the West direction shortly after sunset on 14th Feb (around 7:30pm). Ideal weather conditions (clear sky) are required to see it, but it is just visible to the naked eye.

Constellations
Finally, at least 8 of the brightest stars in the sky are visible in February. This includes Sirius, Canopus, Procyon.
One of our most common targets is of course Orion, reaching his highest point in the sky in the early evening this month, which should give us some pretty good views of the Orion Nebula.

Diagram of the brightest stars in the constellation Orion

January 2013 - Happy New Perihelion!

Our first stargazing session of the new year turned out to be very cloudy indeed, not a single thing to see. The same was also true during our attempts to see ISS fly over Singapore on 2nd & 3rd Jan.
However, as the weather is much clearer and hotter this week, I put a solar filter on our 6-inch refractor attached to the main telescope and took a look at our parent star, the Sun.

Photo of Sun ans sunspot 7th Jan 2013 4:15pm - taken through 6 inch refractor with Samsung SII phone camera. Image is rotated 90deg counter-clockwise, north is on the left, south on the right.

Image of the Sun from NASA satellite SDO (Solar Dynamic Observatory) showing the numbers/names of the sunspots on 6th Jan. The highlight area produce a M-class Solar flare on 5th Jan. This image is in the correct orientation with north at the top.

January is the month when the Earth reaches its closest position to the Sun, (perihelion), which was actually on 2nd Jan.  The difference between Earth's perihelion (closest) and aphelion (furthest) distance is only 3% so it doesn't look any different than usual. There were several sunspots visible on the Sun's surface, areas of magnetic instability and high activity, usually associated with solar flares. 2013 is expected to be the year in which the Sun reaches its solar maximum, the peak of its  11 year natural activity cycle.

For the remainder of January here's what we can expect to see:

Constellations
Most of the brightest stars in the sky are visible during the first part of the year. This includes Orion, Taurus and Canis Major, with the brightest star in the night sky Sirius, lower towards the south-east.

Planets
We've been observing Jupiter for over a month now and its still shining brighter than all the stars. This month its alot higher in the sky, so we should get some nice clear views of its bands of clouds and its 4 Galilean Moons.  64 moons have been discovered around Jupiter, but only its four biggest moons, Io, Europa Ganymede and Callisto are visible through most telescopes.

Position of Jupiter's four biggest moons during Friday night stargazing at SCOB (8pm-10pm).

As a planet orbiting around the Sun, Jupiter appears to move in front of the constellations. Currently, its making its way through Taurus. Since October 2012, Jupiter has been in apparent retrograde motion, meaning its moving backwards in the opposite direction of its original path (prograde)
This apparent retrograde is due to the position of the Earth.

As Earth is closer to the Sun, it travels faster than Jupiter. Both planets are travelling in the same direction but as Earth comes closer to Jupiter and eventually overtakes it, the giant planet appears to move backwards. This current retrograde will last from Oct 2012 until 30th January 2013.

Moon
The Moon moves close to Jupiter on 21st Jan and 22nd Jan. Look out for the bright planet next to the Gibbous moon on these two evenings.
On Friday nights at SCOB, we'll be observing the Moon on 18th Jan (crescent/half moon) and 25th Jan (gibbous moon).
The other significant Moon dates are as follows:

 Happy skywatching!