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Stargazing Basics

 
 

Getting Start

 

A pair of bright eyes, a small flashlight covered with red cellophane and a star map are all you need. Binoculars is a plus but not a must. You don't need telescope unless you want to study the deep sky objects like nebulae and clusters or the planetary features. But then you won't be able to spot a whole constellation as the field of vision is too narrow.

Don't forget to bring along a jacket with you as the temperature will fall at night.

Magic of Star Map

 

Usage of star map

Rotary star map is best for beginners, while monthly star map usually gives more details of the night sky.

Keep in mind that the night sky changes from days to days and hours to hours. A monthly star map shows the night sky at about eight or nine o'clock of that particular month. For every two hours gone, use the star map for the following month.

Star map is simple to use. Just hold it over your head and turn it until the direction indicated on the map points to the same direction in the field.

However clear the sky, only about 3,000 stars at most can be seen with naked eyes. Astronomers rate the brightness of stars by a system of numbers called magnitudes. The fainter the stars, the greater the number they are. The faintest stars that can be seen with naked eyes are of sixth magnitude.

Where To go?

 

Stargazing can be a luxury in Hong Kong where light pollution and high-rise buildings are almost everywhere. To look for a starry sky, the suburb of the city such as Lantau Island and Sai Kung are ideal places. But for beginners, places where street lights, buildings or trees are not obscuring your view too much will be pretty good. Examples are beaches in Southern District on Hong Kong Island, the Shing Mun Reservoir or even the recreational grounds nearby some housing estates.

Clear moonless nights are ideal for stargazing but these might be rare. Even with some moonlight or clouds, you can still see quite a number of stars. They won't be such a nuisance for it could make the finding of the constellations more challenging.

Starry Starry Nights

 

Spotting a constellation with star maps is similar to locating yourself in the field with a terrestrial map. You have to take the bearings, understand the scale and then look for any prominent stars.

To identify directions, use a compass or just to remember the direction where the Sun sets. The Dipper or the big "W" of Cassiopeia are also obvious signs of directions if you already know something about stargazing.

The postures in the diagrams (with arm stretching) illustrate how to measure roughly the distance between two stars.

Measuring hand postures for 20° Measuring hand postures for 10° Measuring hand postures for 1° Measuring hand postures for 6°, 3° & 2°

Starting with Bright Stars

 

Identification of constellations can be made easy by observing the patterns formed by bright stars in the sky.

Spring Curve

The curve stretches from the handle of the Dipper to Arcturus in Bootes all the way down to Spica in Virgo.

(Bright constellations: Ursa Major, Bootes and Leo)

Summer Triangle

This isosceles triangle is composed of Vega in Lyra, Altair in Aquila and Deneb in Cygnus.

( Bright constellations: Lyra, Aquila, Cygnus, Scorpius and Sagittarius )

Autumn Square

This is the abdomen of Pegasus, the Horse. The four stars just give the shape of a square.

( Bright constellations: pegasus and Cassiopeia )

Winter Triangle

It looks like an equilateral triangle. The three bright stars are Procyon in Canis Minor, Sirius in Canis Major and Betelgeux in Orion.

( Bright constellations: Orion, Taurus, Auriga, Gemini and Canis Major )

Stargazing Manner

 

Stargazing Manner - Do not use flashlight to take photos Do not use flashlight to take photos

In a dark place, our pupils dilate. A person will feel discomfort and lost his dark adaptation if a strong light shines on his eyes suddenly. Photos of wispy nebulae and galaxies can only be taken with extended exposure. Not only flashlight will not help, it will become a nuisance.

Stargazing Manner - Use Red Torch for Lighting Use Red Torch for Lighting

Red light is less irritating to the eyes and helps to preserve our night vision. A red torch can be prepared easily by wrapping a sheet of red cellophane, cloth or even a plastic bag over an ordinary torch.

Stargazing Manner - Do not start a fire close to somebody's telescope Do not start a fire close to somebody's telescope

Since flames are bright and the hot air around causes the image to shiver, the surface details of the celestial body cannot be resolved when a fire is around. Use a warm pack or put on more clothes to keep warm.