SnT - Astro chalet

Dear all, 

If you happen to have not checked your email, yet gone to this blog (which I personally think is highly unlikely, but ANYWAY), here are the details for the upcoming chalet on 10 Jan 2009.

Date: Saturday, 10^th January (1 day 1 night)

Location: Aloha Changi, Yacht Club Bungalow B (YCB B) 

Plan:

Time	Activity
6.00-8.20pm	BBQ dinner!
8.30-9.00pm	Wash up
9.00pm-11.00pm	GAMES
11.00pm-8.00am	Sleep/Free and Easy
8.00am	Rise and Shine
8.30-9.15am	Breakfast
9.20-10am	Outdoor Activities
10-10.30am	Pack up and cleaning up of place

Estimated cost per person: ~$S20 (This figure will vary according to the number of people who are coming. If more people are coming, the amount will be lesser).

Map of the place:

Details:

·  Single-storey chalets

·  Fully furnished with:

-      Living room set with TV and games table; dining room

-      3 air-conditioned bedrooms with 1 queen bed and 4 single beds, wardrobes, dressers, bedside tables and wall fans

-      1 bedroom with attached bathroom cum toilet

-      2 common bathrooms, 2 common toilets

-      Toilets with shower heater

-      BBQ pit and fully equipped kitchen

How to get there:

1. By bus and train

·  Take the east bound train to Tampines MRT station

·  Transfer to Bus no. 29

or

·  Take the east bound train to Pasir Ris MRT station

·  Take a shuttle bus that commutes to and from the station

-      Pick-up/Drop-off points:

     Pasir Ris MRT: Taxi stand facing the main road (near Mac Donald’s)

     Aloha Loyang: Outside the Reception Office

Shuttle Bus Service (wef 1 Jan 2008)
from Pasir Ris MRT to aloha loyang	from aloha loyang to Pasir Ris MRT	from aloha loyang to aloha changi**	from aloha changi to Pasir Ris MRT
0800 hrs	-	-	-
0815 hrs	-	-	-
0830 hrs	-	-	-
0845 hrs	0855 hrs	-	-
0915 hrs	-	0930 hrs	0950 hrs
-	-	1015 hrs	1030 hrs
-	1055 hrs	-	-
1115 hrs	1155 hrs	-	-
1215 hrs	1245 hrs	-	-
1345 hrs	1355 hrs	-	-
1415 hrs	-	1430 hrs	1450 hrs
1515 hrs	-	1530 hrs	1550 hrs
1615 hrs	-	1630 hrs	1650 hrs
1715 hrs	1735 hrs	-	-
1845 hrs	1855 hrs	-	-
1915 hrs	1955 hrs	-	-
2015 hrs	2055 hrs	-	-
2115 hrs	-	2130 hrs	2145 hrs
2200 hrs	2215 hrs	-

 2. By car

If you're coming from the north, get the driver to take SLE/TPE, and exit to Loyang Ave (towards Changi Village). *

If you're coming from the west, you can get whoever driving you to either take AYE/ECP or PIE to TPE/SLE, and exit to Loyang Ave (towards Changi Village). *

* Go along Loyang Ave (it's quite a long and windy route) and turn left into Cranwell Road. Changi chalets are located along Cranwell, Gosport, Andover, Leuchars, Catterick, Netheravon, Halton, Sealand and Biggin Hill Roads.

Please inform me by 24 Dec if you're interested. Thanks (:

Anne

Astrophysics night @ MPCC

Astrophysics night at Marine Parade Community Club for those bored during holidays, and for seniors just done with A level and hungry for some astro (:

Interested participants please contact Anne. Thanks loads!

Pulau Ubin camp

Pulau Ubin camp for 3 days 2 nights organised by MPASTRO.

Interested participants please contact Anne.

Thank you (:

CERN comics

from http://www.phdcomics.com

LMAO =))

Orionids Star Party

Last Saturday, after finishing the NJC open day, the astro club went to the East Coast to join the Orionids star party organized by the MPCC astro club. It was an activity open to all the astro clubs in Singapore. As we reached the destination, Anne taught the members how to set up a telescope and align the finding scope. Everything was ready, but the sky became a bit cloudy and the whole group had to wait. Certainly a lot of activities were prepared to entertain us as the backup plan. At midnight, the moonlight pollution flawed the whole plan and it really disrupted the observation to a certain extent. Fortunately, most stars could still be spotted.

Let me tell you how many things I have learned in this star party:Trace the stars. Yeah, you need to know some important stars, like Archenar to help you confirm the direction and then use the star chart to help you have a general idea about the position of the star you want to find. Yes, by using this method, I found Pleiades. That’s really the most thrilling moment. One more thing, next time do not forget to bring a jacket, otherwise your are going to freeze.

Hemiao

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

Optical aberrations

To those who like optics, this is probably one of the simplest summary of optical aberrations that I came across in a thread from Cloudy Nights forum (: Something good to refer to (:

WHAT DO ABERRATIONS LOOK LIKE

ON_AXIS
Generally, not all aberrations are seen on-axis. The on-axis image created by aberrations is as follows:

curvature not seen on-axis.

coma not seen on-axis.

If the stars seem never to focus to a fine point, but at best remain slightly bloated and are still circular, and it cannot be focused out it is probably spherical aberration.

If the star seems to not come into sharp focus it may be astigmatism. If astigmatism is severe, then on-axis focused images will show a very small cross, never a fine pinpoint. Passing in and out of focus will show the out-of-focus image to flip orientation by 90°.

Longitudinal CA will produce softness of image focus of perfectly on-axis objects because all colors in the spectrum will not come to focus at the same point. Sometimes seen as a small circular band of color arounnd a finely focused star point.

OFF_AXIS
As for how you notice stars in the outer fov, the image created by aberrations is as follows:

If the star seems slightly bloated, but it can be refocused down to a finer point, then it is curvature.

If the stars seem flared as wedges with the point towards the middle and the flared wedge toward the outer edge, then it is coma. It cannot be focused out.

If the stars seem slightly bloated but are still circular, and it cannot be focused out it is spherical aberration.

If the star seems slightly bloated and slightly elongated than it is astigmatism. Astigmatism will show elongated images off axis. If astigmatism is severe, then on-axis focused images will show a very small cross, never a fine pinpoint.

If you have both astigmatism and coma, the off axis images will look like comets with an oblong axis, or like seagulls.

Longitudinal CA will produce softness of image focus of perfectly on-axis objects because all colors in the spectrum will not come to focus at the same point.

Lateral CA will produce color fringes around all bright objects when viewed slightly off axis, but you should see a different color towards the lens center than you see towards the lens edge.

Clear skies,
Anne (:

Mooooooooon

The moon taken by my lousy camera phone through a Baby-G Takahashi refractor at Astronomy 2008 today (: No processing. Because I don't know how :|

Clear skies,
Anne (:

13 Zodiacal Counstellations

I just now know that there are actually 13 zodiac constellations. Ophiuchus is added in. It is not the latest news, but already dated. But I still want to share with those who do not know it. Modern constellation boundaries were established around 1930, putting part of the ecliptic in Ophiuchus. The astrologers insist on 12 counstellations, because the concept of the astrological zodiac is to divide the ecliptic into twelve equal segments. These signs are named after the constellations they aligned with in the time of Ptolemy, who invented "modern" astrology about 1850 years ago, but really have nothing to do with the constellations. Since Ptolemy, precession of the equinoxes has shifted the alignment by about 25 degrees.

Interesting question

In Pole to Pole, an early science fiction story by George Gtiffith, three explorers attempt to travel by capsule through a naturally formed tunnel directly from the South Pole to the North Pole. According to the story, as the capsule approaches Earth’s centre, the gravitational force on the explorers becomes alarmingly large and then, exactly at the centre, it suddenly but only momentarily disappears. Then the capsule travels through the second half of the tunnel, to the North pole.
Check Griffith’s description by finding the gravitational force on the capsule of mass m when it reaches a distance r from Earth’s centre. Assume that Earth is a sphere of uniform density p.

This is a question I saw from a physics book. If you work it out, you can find the interesting part.
Hint: use Newtonian Gravitation law. F=G(Mm)/r^2. Remember Newton’s shell theorem: a uniform shell of matter exerts no net gravitational force on a particle located inside it.

I will show the answer SOON! ^.^

Announcement

Astro members:
Please take note of this announcement. Pls check your mail for the schedule and the allocation of the group presentation. There is also an attatched file of the EXCO's email address.
!!!Bring $29 dollars in next session for the astro jackets if you have ordered it.

Event: Astronomy 2008

Hi all! Sorry for the lack of updates recently :P

Anyway! There'll be no astro session next week, so if you're free on Saturday, then do come for Astronomy 2008, an event organised by Singastro forum, at Singapore Art Museum, 10am-5pm 16th August. After that there'll be mass stargazing session outside SMU nearby, so you can stay and join the fun as well!
More details can be found here.

Clear skies,
Anne

P.S. I'm going! So if anyone else is, do tell me, then we can all go together yeah! :D

Circumhorizontal arc

Anyone can spot a tiny rainbow among the cirrus cloud?
*hint hint: look above the lamppost!*
If you can't, never mind then, because I think my camera is quite lousy afterall. Anyway, for those who can, what you see is essentially a phenomenon called circumhorizontal arc.

A circumhorizontal arc is created when light is refracted through ice crystals in cirrus clouds. It occurs when the sun is at least 58 degrees above the horizon, and only in presence of cirrus clouds. In contrast to rainbow, circumhorizontal arc is seen on the same side of sky as the sun (so in case you are wondering, the sun in the picture is blocked by the trees).

Below are more pictures of this beautiful phenomenon:

(from http://upload.wikimedia.org/wikipedia/en/2/2d/Circumhorizontal_arc.jpg)

(from http://upload.wikimedia.org/wikipedia/commons/2/22/CircumhorizonArcIdaho.jpg)

(from http://upload.wikimedia.org/wikipedia/en/0/09/Circumhorizon_Arc.jpg)

(from http://upload.wikimedia.org/wikipedia/commons/c/c8/Ohlookarainbow.jpg)

Other related phenomena include iridescent cloud, circumzenithal arc, Kern arc, infralateral arc, supralateral arc, tangent arc, Parry arc, halo, parhelic circle, sundog, etc. in case this is not enough for your knowledge greed :D

I'm still wondering whether this is astro-related. lols

Clear skies,
Anne (: