Index of Topics
1. When is the Observatory open?
We are open once a week from January to mid-November, every Friday night (except on public holiday). You may arrive and leave at any point between 7.45pm and 10pm.
We are open on every Tuesday and Friday between mid-November and December, 10am to 12pm. There is no night stargazing during this period of time.
For updates, please check out our Facebook page.
2. What is there to do on stargazing nights?
The main activity is to take turns looking through the telescopes at various objects visible in the sky. There are basic astronomy talks every 2nd Friday of the month and talks by other invited guests on special nights. For updates, please check out our Facebook page.
3. How many people attend each week?
Non-peak (school term time): About 50-100 people
Peak times (Public and School holidays): About 100-200 people
Queuing time at the telescope may vary between 2mins and 20mins, depending on the number of people attending that night.
Queuing time at the telescope may vary between 2mins and 20mins, depending on the number of people attending that night. For your safety, only a limited number of people may be up at the big telescope per 15 minutes. You may collect a time card outside the classroom to select a time slot to view the big telescope.
4. Will there be people giving explanations on what can be seen in the sky?
Yes, Science Centre staff will be on duty to operate the telescopes, give explanations and point out objects in the sky. Student volunteers may also be on duty to answer questions. In addition, Science Centre also receives help from members of The Astronomical Society of Singapore, TASOS, who assist in explanations and sometime bring along their own telescopes.
5. Can I take photographs?
Yes, photography is permitted inside the Observatory. However, during the viewing of objects that require the darkest conditions, flash photography may be prohibited. Taking a photograph through the telescope is not recommended and will only be permitted when the queuing/waiting time is very short.
1. What planets can we see?
At various times of the year we will look for at least one of the four brightest planets - Venus, Jupiter, Saturn and Mars. Uranus and Neptune are also visible but are so faint and small (due to being far away) that they are seldom viewed. Mercury is often too close to the Sun to see or is too low to see by the time stargazing session begins.
2. How big do planets look through the telescope?
Due to their great distance from Earth all planets will appear small in most telescopes; their apparent diameter being no more than 1cm. Despite the small image, many good quality telescopes give incredibly sharp and detailed views.
3. Can we see the Moon through the telescope?
Yes, enough to magnify small areas of the Moon’s surfaces to give close up views of craters and mountains. Crescent Moons and Half Moons are one of the best sights through the telescope. Full Moons are not good for viewing through telescopes because the brightness and lack of shadow on the surface make it difficult to see under high magnification.
4. Can we see the American flag on the Moon?
No. Not even with the world’s biggest telescope. It’s too small.
5. What do stars look like through a telescope?
Stars are incredibly far out in space, beyond the Solar System. In all telescopes, stars will always be points of light no matter how much magnification is used. Through the telescope we are able to see a star’s colour. We also use the telescope to view stars that cannot be seen with our own eyes such as double/binary stars and star clusters (small faint groups of stars).
6. Can we see Galaxies?
Yes. They are best seen using low magnification and with dark, moonless skies. They are very difficult to see in Singapore’s brightly lit sky.
1. How far can the main telescope see?
How far it can see depends on sky conditions,light pollution, brightness and size of the object. It can see things 100 metres away, like buildings and things millions of light-years away, like distant galaxies. A distant bright object may be seen but a close faint object may not be seen.
2. How many telescopes does the Observatory have?
The Observatory has one large, main telescope (16”/40cm aperture) and several smaller telescopes. The main telescope is situated on the roof of The Observatory building and is used during most stargazing nights. A smaller Observatory or smaller portable telescopes are used during special events and busy periods.
3. What type of telescope is in the main Observatory?
The main telescope is a reflector (Cassegrain type) meaning it uses mirrors to focus light into the eyepiece lens. It has an aperture of 40cm (16 inch) and a total focal length of 5.2 metres.
The main telescope is also equipped with a second/sub telescope mounted on the side. The sub telescope is a Kepler refractor (using lenses) it has an aperture 150mm (6 inch) and focal length of 1.5 metres.
4. What is the magnification?
In all telescopes, magnification can be altered to suit a variety of purposes by changing the power of the eyepiece lens. Different objects require different magnifications. Magnification depends on the focal length of the telescope and eyepiece.
Common magnifications used in the main telescope:
Using a 40mm eyepiece gives 130x magnification
Using a 26mm eyepiece gives 200x magnification
Using a 15mm eyepiece gives 347x magnification
5. What makes a good telescope?
Aperture (diameter, width) is an important factor. The wider the telescope, the more light can enter it, the better it can see. Telescopes can be refractors (using lenses) or reflectors (using mirrors) of which there are many types (e.g. Cassegrain, Newtonian, Dobsonian, Maksutov).
Sturdiness is also an important factor to minimise shaking and vibration. Standard beginner scopes: S$200-S$1000 (depending on quality and whether they are computerised or not)
There are many good brands, e.g. Celestron, Meade, Orion, Televue, Vixen and many more.
1. What is a light-year?
The distance light travels in a year through space, about 9.5x1012 km.
2. What is the difference between stars and planets?
Stars are huge and made of hydrogen, which under immense pressure is converted to helium and energy. Stars are very far away. In our sky they appear fixed in defined patterns called constellations.
Planets are large round objects that orbit stars. The planets in our solar system travel around the Sun, they are much closer than stars. In our sky they appear to move in front of the stars, gradually changing position from one constellation to another.
3. What is a Dwarf Planet?
In 2006 the International Astronomical Union defined a dwarf planet as having a round shape like a planet and orbiting around the Sun. The key difference being that a dwarf planet does not orbit in the same way as a planet. Dwarf planets do not have a clear orbit; they share their orbit with other rocky objects or cross the path of planets. As of September 2008, 5 objects have officially been named dwarf planets: Pluto, Eris, Ceres, Makemake and Haumea.
4. What is a Constellation?
A shape made out of stars, some represent animals, people, or objects. There are currently 88 defined constellations, of which 48 are based on ancient Greek mythology and stories.
5. What is the Zodiac?
An imaginary line that travels through 12 constellations or star signs as it encircles the Earth. These constellations lie in the same line of sight (or plane) as our solar system. This means that from our position on Earth we see the Sun, Moon and planets appear to move in front of these 12 constellations.
6. When can I see my star sign?
The dates given for the 12 star signs (constellations) used in zodiac horoscopes indicates the time of year in which the Sun is located in front of that specific star sign/constellation. This occurs in the daytime meaning the star sign cannot be seen due to the Sun’s brightness.
To see your star sign you have to wait 6-8 months after the horoscope date, at which time the star sign will be visible in the night sky. For example, the horoscope date for the star sign Sagittarius is given as November 23rd to December 22nd. The constellation Sagittarius is visible at night from July to September.
7. What is the difference between astronomy and astrology?
Astronomy is a science. Information is obtained by direct observations, taking measurements, critical analysis and mathematical predictions. This information is used to give a greater understanding of the universe as a whole.
Astrology is a belief that celestial bodies (stars, planets, Sun and Moon) influence our life, behaviour and events. Although it uses some astronomical observations and predictions it is based upon the arrangement and movement of celestial bodies as seen from Earth.
8. Is there a best time to see each constellation?
Yes. As the Earth travels around the Sun during the year it points towards different constellations.
Constellations are seasonal, for example:
Jan-Mar – Orion, Taurus, Gemini, Canis Major
Mar-May – Canis Major, Leo, Ursa Major
May-Jul – Virgo, Southern Cross, Centaurus
Jul-Sep – Scorpius, Sagittarius, Aquila, Cygnus
Sep-Nov – Cygnus, Aquarius, Capricorn, Pegasus
Nov-Jan – Pegasus, Andromeda, Taurus, Orion.
Click here to access the Glossary of Astronomical Terms.