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Posts from the ‘Planetarium’ Category

Barely a minute to capture information about Pluto

An artist's impression of the New Horizons spacecraft flying past Pluto.  The closest approach will be on July 14.  CREDIT: JHUAPL/SwRI

An artist’s impression of the New Horizons spacecraft flying past Pluto. The closest approach will be on July 14. CREDIT: JHUAPL/SwRI

The QVMAG Planetarium is partnering with astronomers from the Southwest Research Institute in the USA to carry out valuable observations of Pluto next Tuesday morning.
QVMAG Acting Director Andrew Johnson said US astronomers Jeff Regester and Charles Watson will gather data as Pluto briefly passes in front of a distant star just before 3am.
‘QVMAG Planetarium staff, including QVMAG astronomer Martin George, will monitor the changing light,’ said Mr Johnson.
Martin George described the event in which the star will fade gradually before being completely obscured as occurring for the same reason that the Sun and Moon appear much less bright when their light passes through more of our atmosphere at rising or setting.
As Pluto passes in front of the star, the astronomers will monitor the drop in the star’s light.
‘If the sky is clear, these observations will enable us to learn more about Pluto’s atmosphere, and even Pluto’s exact position in space.
‘The whole event, known as an occultation, will take little more than a minute,’ he said.
‘In addition, accurate timing of the event assists with information about the exact direction of Pluto in relation to the star,’ Mr George said.
This study enhances information gathered from prior observations. US Astronomer Jeff Regester said this is the third visit to Tasmania for such observations. Mr Regester said the occultation, in conjunction with the arrival of New Horizons at Pluto, is especially important.

‘The New Horizons spacecraft is the very first mission to Pluto, and will make a flyby on 14 July.
‘The Tasmanian observations, combined with results of the mission, will provide more information about Pluto,’ he said.
An additional six teams will make observations of the occultation at the Greenhill Observatory north of Hobart, on New Zealand’s North and South Islands, and at Siding Spring Observatory in New South Wales.
Demoted from planetary status in 2006, Pluto is now called a dwarf planet.

For further information
Irene Burlein,  Media Officer
T 03 6323 3758

One is an image of Charles Watson (left) and Jeff Regester.  Suggested caption:  US astronomers Charles Watson and Jeff Regester testing their portable equipment in readiness for the Pluto occultation.   CREDIT: QVMAG

L-R:  Charles Watson and Jeff Regester, US astronomers testing their portable equipment in readiness for the Pluto occultation. CREDIT: QVMAG

Easter Eclipse

A total lunar eclipse will, weather permitting, be seen on Saturday evening, 4 April with Tasmanians well located to obtain a good view.

The event will be visible in its entirety from here and from all over Australia but at only five minutes long, totality will be very short indeed. Indeed, it is the shortest period of totality for a lunar eclipse since the year 1529!

A lunar eclipse occurs when the Moon moves through the Earth’s shadow in space.  An eclipse does not occur every month, because the Moon’s orbit is tilted with respect to the Earth’s orbit around the Sun, and so it usually misses the shadow.

I saw my first total lunar eclipse when I was growing up in Sandy Bay, a Hobart suburb. I can remember sitting on the lawn with a school friend and watching the Moon turn a deep red colour. It was very impressive!

The Moon is a reddish colour even when it is completely within the Earth’s shadow because some sunlight is bent in the Earth’s atmosphere and falls within the shadow cone onto the Moon. Less blue light than red passes through, leaving an obvious red colour.

It is completely safe to watch lunar eclipses, because they do not involve looking at the Sun. Binoculars offer an excellent view and I recommend doing this especially during the partial phases of the eclipse, to see more clearly the curvature of the Earth’s shadow.

The event begins at 9:16pm (Daylight Saving Time), when the full Moon will start to move into the main part of the Earth’s shadow. By 10:58pm, the Moon will be entirely within the shadow, but it will remain completely engulfed only until 11:03pm.

Because the Moon will be just grazing the shadow’s inner edge, defining the exact beginning and end of totality is difficult. For this event the quoted duration is anything from 5 to 12 minutes. So the Moon will be a beautiful sight through the main five-minute period and for a few minutes before and after, changing little in appearance through that time.

Although during some total lunar eclipses, the Moon becomes so dark that it is hard to see at all, for this event it is expected to remain very easy to see and more orange-red than deep red because the Moon will be so close to the interior edge of the Earth’s shadow.

After totality, the Moon will gradually once again become bathed in sunlight, and by 12:45am, it will appear as a normal, bright full Moon.

The next total lunar eclipse visible from Tasmania will not occur until 2018.

Caption for photo:  Last October's lunar eclipse at the beginning of totality.  Photo:  Martin George

Last October’s lunar eclipse at the beginning of totality. Photo: Martin George

Martin George, QVMAG Planetarium Manager