Updates!

Dear astro members,

Here's our schedule for Term 4, 2008.

Orionids star party (18th - 19th Oct 2008)

Attendance for this event will be counted, and there'll be 1 way transport provided from school to Marine Parade Community Club. Since it's after Open Day, we'll go head straight there after cleaning up, and have dinner together (:

All members please reply to njastro at gmail dot com to confirm your attendance for the star party. Thanks!

Guest lecture on Wednesday 22nd October 2008

There'll be a lecture by Mr. Leek Meng Lee on our last session of the year! Title and description of the talk is as follow:

Title: From your physics textbooks to the Large Hadron Collider to the start of the universe

Introduction: This talk brings you on a journey, starting from your Physics textbooks to Man's quest in understanding the start of the Universe. We will start from the Physics at the JC level and bring it (conceptually) over to the highest Physics theories that we have. This is needed to understand the most intricate interactions between matter, energy, space and time. During the start of the Universe, we have these intricate interactions going on. Due to the high temperature and high energy, these interactions are in their most extreme version. Man attemps to reproduce such conditions on Earth through particle collider machines, the latest and the most advanced one is LHC (Large Hadron Collider). We will take a peek into this monster machine and how it will tell us the start of the Universe.

After the talk, we'll head over to Hwa Chong Institution for a brief observation session and socialise and make friends (:

Til then!

Spot the mistake! answer

Hey all! I'm so glad that exams are all over =D Now, back to our usual activities...

A few weeks ago I posted this.

Anyone managed to spot the mistake? If you couldn't, no matter, read on!

Everyone must be familiar with the terms "Big Dipper" and "Pole star", etc. both of which are supposedly useful in helping you locate the North direction and navigate your way when you're lost, as depicted in popular culture.

Now popular culture, more often than not, uses the terms interchangeably, while there is a marked distinction between the two.

A quick glance back to a diagram of the celestial sphere shows you this:

Image taken from http://www.astro.columbia.edu/~archung/labs/fall2001/images/celestial-sphere.jpg

As seen, the North Celestial Pole (NCP) is the point where the entire celestial sphere, or "sky", appears to rotate about. The NCP also happens to be marked by a star of apparent magnitude 1.97, thus it appears stationary as the sky rotates about the NCP. Polaris therefore is a good pointer to the North.

Polaris aka Pole Star belongs to the asterism Little Dipper, whose picture is shown below:

Image taken from http://my.execpc.com/60/B3/culp/astronomy/fig/LittleDipper.gif

Another good North pointer is the Big Dipper.

Image taken from http://my.execpc.com/60/B3/culp/astronomy/fig/BigDipper.gif

Big Dipper and Little Dipper share a little bit of resemblance, thus explain the names.

The bigger asterism, due to its close angular distance from the NCP (as seen at 2 o'clock on 1st picture), is also a good North pointer. It however does not stay motionless on the sky, and thus rotates about the NCP just like the rest. Its stars are brighter and the asterism is more recognisable than Polaris, thus Big Dipper can be used to find Polaris, then North.

As such, referring back to the image we had last time...

The image shown was that of Big Dipper, NOT Little Dipper, therefore our Pole Star appears to have been misplaced, removed from Little Dipper and placed at Big Dipper instead. Big Dipper thus is not stationary, or "always there", and as it goes, the boy deceived the poor little girl -_-

ALSO, Polaris, at an apparent magnitude of 1.97, is not "the brightest star". Our brightest star excluding the Sun would have to be Sirius of Canis Major, at apparent magnitude -1.46. For more information, just wiki.

Hope this clears up some's misconceptions!

Clear skies (:

Large Hadron Rap

At 1:30AM Wednesday, September 10th, scientists working at CERN's Large Hadron Collider will make their first attempt to circulate a beam of particles through the entire LHC. Initial tests through a part of this humongous particle accelerator were carried out on 8th-11th August, and the first high energy collisions are scheduled to take place after 21st October 2008.

As physics fanatics around the world rejoice (or wail about the world's end, for that matter), countless articles and clips and songs are created, this being one.
Enjoy!



Clear skies,
Anne (:

Sentosa Get-together star party photo

Some of us went, and so here's the photo.

A technique to star-hopping for beginners! =P

At this point of time, we're living in the world of high-technological devices. With just a slight push on the button, we could be pleased see from the nearest object in the dark sky to the farthest possible range of DSO!
However, enjoying astronomy is not always equal to satisfy with newly invented tools and machines, but also filled with some interest dating back to the most basic: manual star-hopping! =D
...
So what would you need? Simply a beginner's star charts and a decent binoculars or small telescope! For better joy, a telescope is recommended.

Once you have the atlas, the next step is to determine the visual field of the eyepiece you are using. In order to determine the power given by the eyepiece, you should divide the focal length of the instrument by that of the eyepiece. If for example we have an eyepiece with an apparent field of 50 degrees, which assembled to the telescope gives a power of 30x, then the visual field of the eyepiece will be equal to the apparent field divided by the magnifying power of the eyepiece, that is 50/30, which is about 1.7 degrees.

If you don't know the apparent field of the eyepiece the matter becomes a little more complicated... In order to find out the visual field of the eyepiece in this particular case, you should direct the instrument to a star as close as possible to the celestial equator, set the star at the edge of the visual field and measure the time it takes for the star to cross the eyepiece, without moving the instrument. Knowing that a star near the celestial equator will move one degree every four minutes, you can calculate the visual field of the eyepiece.

In order to find a celestial object with the star hopping method, the visual field of your eyepiece should be as large as possible, so don't use great magnification. This way you will be able to see several stars in the field, and will have reference points. Only when you have found the desired object should you use eyepieces with great magnifying power.

Next then to the checking on telescope.

Check the alignment of your finderscope: Find a bright star or planet, center it on the crosshairs, and make sure it is in the dead center of the 25mm eyepiece. It will be impossible to star-hop succesfully without a well-aligned finderscope. Locate the finding chart for the object you're looking for.

Center the finder on the bright, naked-eye star near the object. Knowing the field of view of your finder scope, match the stars on the finding chart with the stars you see in the finder scope. While looking through the finder scope, move the telescope so that the finder field of view moves in the direction of the object you want, but keeping some stars in the field of view so that you always know where you are. You will probably want to move only one axis at a time. You will need to move far enough that the fine-adjustment knobs won't be good enough; you'll have to unclamp the telescope and carefully move it by hand

Repeat the previous step until you get the finder scope centered on the object you are looking for. Particularly with nebulae and galaxies, you may not be able to see the object you're looking for in the finder scope! If this is the case, then you must center the crosshairs of the finderscope on the right spot so that the pattern of stars you see around the crosshairs in the finder scope match the pattern of stars you see on the finding chart.

Look in the telescope for the object. Start with the 25mm eyepiece. Focus the telescope as best you can. If you're looking for something fuzzy, you will have better luck by focusing on other stars in the field of view. If it's a double star you're looking for, you should be able to see it. If the star doesn't look double, star at it for a little bit; it may be that it's a very close double that you're having a hard time splitting! Or, you ended up on the wrong object....

If you're looking for a faint fuzzy object, like a galaxy or nebula, if you can't see it at first spend a couple of minutes looking through the telescope. Move your eye around; you may not be perfectly centered on it!You often get a better view of dim objects by using averted vision. The receptors that are most sensitive to dim light (the rods) are concentrated more away from the center of your field of vision. By looking a little off to the side of a dim object, the light from that dim object then falls on those dimmer receptors. Try this, to see if you can get a better view of a nebula, cluster, or galaxy.

Taken from:

http://www.nightskyinfo.com/star-hopping/

http://brahms.phy.vanderbilt.edu/a103/labs/tl_starhop.shtml

Spot the mistake

So. As the title says, can you spot the mistake in this manga script? No prize for the winner though, but it's good exercise once in a while (:

Will post the answer when I feel like it lols.

By the way, this is from an average shoujo manga named Orange Planet. You really shouldn't make the same mistake as I and waste your time with this XD

Clear skies,
Anne (:

Hanny's Voorwerp... new discovery by a primary teacher!

"A little bit news here and there" now showing... The New Cosmic Ghost, Hanny's Voorwerp !
...

"Hanny's Voorwerp" is simply "Hanny's object" ("Voorwerp" means "object" in Dutch!)
...
Hanny is just an ordinary primary teacher like any one would think of. As a member of the web GalaxyZoo.org, she was just doing her usual work that was to classify the pictures uploaded there. While poring through the photos, something has captured her eyes: an unusual object with peculiar green colour and also a big halo in the middle of itself.
Lying near the spiral galaxy classified IC2497, this object stands out because of its shape, together with the g magnitude so bright as to suggest a single very strong emission line. This object is different from any classified galaxies; this could suggest that a new category of galaxy might be created!!!

After many research and checking of a lot of observatories and astrophysicistss, The only hypothesis is that this so-called "Voorwerp" is a small galaxy but act like reflection nebula that reflected light from a quasar event in the centre of IC2497 around 100,000 years ago.

People from the Hubble Space Telescope have promised to take a look closer into this object in 2009. Maybe at this point of time, we'll have a clearer picture on what the Voorwerp really is? =P