In the Sky Tonight

last SG · 2005-08-23T14:26:28+00:00

Spotting the Summer Triangle Wednesday, May 17, 2006 Looking East-Northeast in Late Evening In the east-northeast in late evening, you'll find a famous...

poon cho tang SG

Wednesday, August 17, 2005
Looking West-Southwest After Sunset

There are three bright objects lighting up the western sky this evening after sunset. Low in the western horizon is the sky's brightest star-like object, Venus. If you look to Venus' upper left about fifteen degrees, you will encounter the planet Jupiter. If you turn your gaze eight degrees to the left of Jupiter, you will find the bright alpha star Spica, of the constellation Virgo the Maiden. Since the month of May, viewing of Venus in the west-northwest for us in the Northern Hemisphere has been poor, and confined to early evening twilight. This will continue to be the case until September. By October of 2005, Venus will be visible until two hours after sunset, when it will then set. In November, when Venus reaches greatest elongation, or greatest angular separation from the sun (47 degrees for Venus), it will continue to improve its visibility for the northern hemisphere. This visibility will continue to improve until December 9, 2005, when Venus will attain its greatest brilliancy in its cycle. At this point, it will be setting about three hours after sunset, and is located high in the southwest just before the end of evening twilight.

BabyLover SG

mi wun get to c it again… y not d eastern sky…

poon cho tang SG

u dun have to stay in the west to look at the western sky, just look towards the west Laughing

SBS1908B SG

Seen liao.

BabyLover SG

huh? u seen it ardy??

BabyLover SG

oso cant c de...

hope bissy doesnt miss it dis time Laughing

poon cho tang SG

y? u r blocked by bukit timah? Laughing

BabyLover SG

actually hor.. i dunno my hse which part is west leh..kekeke... but the lastime i look every window oso cant c.. so conclusion is im blocked Mr. Green

BabyLover SG

upz for pple to c!

BabyLover SG

how was it? did u c? anyone seen it??

poon cho tang SG

nothing, it was cloudy Laughing

BabyLover SG

har....

den tonite wil stil hv??

poon cho tang SG

Friday, August 19, 2005
Looking East-Southeast Before Dawn

If you are up in the early hours of dawn, youll find that one of the most prominent constellations in our skies has returned. The constellation Orion the Hunter can be found in the east-southeast a couple of hours before sunrise.

In the constellation Orion, if you were to draw a line from Earth to each star would their distances be the same? The stars in Orion aren't the same distance from Earth. Most stars in constellations aren't physically bound to each other in any way. A notable exception is in the case of the stars of the constellation Scorpius the Scorpion. Instead, they lie at very different distances from Earth. In the case of Orion, the brightest stars in the constellation lie at similar distances, hundreds of light-years away. Rigel is 773 light-years away, Betelgeuse 522 light-years, Bellatrix 243 light-years. These are all just estimates, of course. That's in contrast to the nearby bright star Sirius, which is only 9 light-years away. It's no coincidence that these stars in Orion lie at such similar distances.

When we look toward Orion, we're looking toward the outer edge of the galaxy . . . but into the very arm of the galaxy in which our sun resides (or near which our sun resides . . . astronomers aren't sure). So these bright stars in Orion just happen to be giant stars in that nearby spiral arm of our Milky Way galaxy.

poon cho tang SG

they will still be there Laughing

jay_rocks SG

hah. ytd saw a veri bright moon. dunno izzit one of the planets. veri bright sia. the light shone onto my bed sia.

jay_rocks SG

pct, remind me when i at the blog

poon cho tang SG

Friday, August 19, 2005
Looking East-Southeast At Nightfall

Why does the moon appear so large when close to the horizon; as opposed to high in the sky? Is it the perspective of being close to the Earth and trees, etc.?

The moon illusion is a pretty confusing phenomenon. Lloyd Kaufman and James Kaufman, a father/son team of scientists, published what still stands as the best explanation of the moon illusion -- in part because it's based on experimental studies on how people perceive the moon. The Kaufmans basically concluded that people perceive a moon on the horizon to be farther away than a moon seen overhead. Of course, it's not true, but our brains think it is. Then our brains appear to drive home this perception by exaggerating the moon's apparent size to our eyes.

Tonight's full moon is considered to be a blue moon, as it is the third full moon of four between the June solstice and the September equinox.

poon cho tang SG

Sunday, August 21, 2005
Looking East-Southeast Before Dawn

A skywatcher wrote, I wanted to ask about the brightest Dog Star Sirius. You are right to suggest that theres more than one Dog Star. The other one is Procyon in the constellation Canis Minor the Lesser Dog. The brightest Dog Star, Sirius, is in the constellation Canis Major the Greater Dog. Its visible now in the east-southeast before dawn. You can always find Sirius by noticing that the three medium-bright Belt stars in the constellation Orion point to it.

The name Sirius comes from a Greek word that means the "sparkling one" or "trembling one." Sirius got this name because, when it begins its ascent in the southeast each year, we see this bright star through an extra thickness of Earths atmosphere. The atmosphere causes Sirius to flash its many colors as the star's light is refracted or bent. But, when this star is at its highest in the south, its light appears more steady, and the star shines with the fierce brightness of a diamond.

People sometimes refer to the hottest part of summer as the dog days of summer. The dog days are named for the Dog Star Sirius, which is the brightest star visible from either of Earth's hemispheres. It's prominent in the evening during the Northern Hemisphere winter. But its appearance in the summer has also been noticed for many thousands of years. Around this time of year, after being behind the sun for awhile, the Dog Star reappears before dawn.

The early stargazers believed the combination of the sun and Sirius actually caused the hot weather, when the two are so near each other in the sky. The dire influence of the Dog Star was also said to cause fever in men, and madness in dogs.

BabyLover SG

hope can c sumting dis time Laughing

poon cho tang SG

Monday, August 22, 2005
Looking East-Southeast Before Dawn

On todays chart, we have marked the most prominent constellations in the east and southeast before dawn now. You might notice that you can draw a circle on the sky, using most of the bright stars here. If you start at Capella, you can draw the imaginary circle clockwise to Aldebaran, Rigel, Sirius, Procyon, Pollux and Castor.

This pattern of stars on the skys dome is sometimes called the Winter Circle. All of these stars, along with the planet Saturn, will be shifting into the evening sky by this winter. These same bright stars can be seen before dawn every late summer and early fall. And they can be seen in the evening every winter.

Saturn moves around the sun only once in every 30 earthly years, and thus it moves only very slowly on our skys dome. Its been moving among these stars for several years now. The planet Mercury wont be following these bright stars into the evening sky. Mercury orbits the sun inward from Earths orbit, and so its visible only in the west after sunset or in the east before dawn. Mars, however, is now making its way into our evening skies as we speak. You can find it rising now in late evening before midnight in the east-northeast. By dawn, the red planet is high in the southwest.