Year: 2013

Daily cosmobite: meteor shower

December 13, 2013

Early on Saturday and Sunday mornings we can view the Geminid Meteor Shower, one of the year’s best. The meteors or streaks of light can appear all over the sky, but those associated with the shower can all be traced back to a point in the north near the constellation of Gemini, the Twins.

Daily cosmobite: the life of stars

December 12, 2013

Some stars live longer than other ones. It all depends on their mass. Hot massive stars use up their fuel very quickly and die spectacularly after only a few million years. In contrast a cooler, less massive star like our own Sun is expected to keep shining for 10 thousand million years.

Daily cosmobite: happy birthday Annie!

December 11, 2013

Pioneering female astronomer Annie Jump Cannon was born on this day in 1863 at Dover, Delaware in the United States. Working at Harvard College Observatory she classified almost 400,000 stars by their spectra and sorted them into spectral classes in a scheme of her own devising.

Harry lists the super flares of the current solar cycle 24 and hopes for more

December 10, 2013

Flares stronger than class X1 during the current solar cycle plotted as bars. Some have been shifted a little to avoid overlapping. Sketch and copyright Harry Roberts ©, all rights reserved Witnessing a ‘great’ solar flare is one of astronomy’s rare ‘treats’: they are uncommon at any time – and seeing one is a revelation!

Daily cosmobite: the wonderful star II

December 10, 2013

The variable star Mira is high in the northern sky. It is a red giant star with a bloated atmosphere that is 200 times the width of our Sun. When the star is at its faintest its temperature is only (!) 2000 degrees Celsius.

Daily cosmobite: the wonderful star

December 9, 2013

In the early evening the star Mira, "the wonderful", is high in north in the constellation of Cetus the Whale. Mira's brightness varies over a cycle of about 11 months. At its brightest it is easily visible to the unaided eye while at its dimmest it is far too faint be seen even from a dark spot.

Daily cosmobite: Mt Wilson telescope anniversary

December 7, 2013

On this day in 1908 the first large reflecting telescope since Melbourne’s Great Melbourne Telescope received its 60-inch or 1.5-metre wide mirror at Mt Wilson outside Los Angeles. The next evening was “first light” for the telescope, which astronomers still use to observe the activity of Sun-like stars.

Daily cosmobite: stars in the south

December 6, 2013

In the early evening we see Canopus the brightest star of Carina the Keel high in the southern sky. To its right or west is Achernar the brightest star of Eridanus the River. Further to the right, almost due west, is Fomalhaut the brightest star in Piscis Austrinus the Southern Fish.

Bright star explosion near the Southern Cross_Nova Cen 2013

December 5, 2013

Where to look for Nova Cen 2013 from Sydney at about 11:30 pm on 5 December 2013. Finding chart Nick Lomb Australian amateur astronomer John Seach who lives on Chatsworth Island, which is between Grafton and Lismore in northern NSW, has discovered a star explosion known as a nova near one of the pointers to the Southern Cross.

Daily cosmobite: Venus and the Moon

December 5, 2013

The bright planet Venus is low in the western sky each evening. Through a telescope it now appears as a large crescent that is becoming thinner each evening. Tonight the crescent Moon is below Venus, while on Friday evening it is above and to the right or north of the planet.

Venus is at its best in December 2013

December 4, 2013

Venus photographed through a small telescope during evening twilight on 30 November 2013. Though by eye the planet appeared as a crescent, the compact camera held up to the eyepiece could only indicate that Venus was not a complete disc.

Daily cosmobite: Rogerfederer approaches

December 4, 2013

Is champion tennis player Roger Federer coming early to play at the Australian Open? No, but today the space rock named after him, 230975 Rogerfederer, is at its closest to Earth for the year at a distance of 264 million km.

Harry welcomes the re-emergence of active sunspot group AR11875

December 3, 2013

A comparison of sunspot AR11875 on 26 October 2013 and the new sunspot AR11890 17 days later. Sketch and copyright Harry Roberts ©, all rights reserved The Sun poses many puzzles – some yield to a bit of sleuthing; others remain inscrutable.

Daily cosmobite: stars in the east

December 3, 2013

At this time of the year we can see many bright stars in the evening sky. If we start from the east we find Sirius, the brightest star in the sky. Procyon, the brightest star of the constellation Canis Minor the Little Dog is below and to the left or north.

Daily cosmobite: start of summer

December 2, 2013

Summer started yesterday in Australia. This convention is different to that in many other countries which start their summer three weeks later on the date of the solstice. Starting at the beginning of the month suits the Australian climate as the hottest days tend to come in the middle of the three summer months.