Mars up close Above us, our nearest, potentially habitable planet is being explored by three spacecraft in its orbit and two on its surface. But the closest the rest of us are likely to come to Mars will be on April 14, when the red planet will be at its closest approach to Earth - a relatively short hop of 90 million kilometres away. On average, Mars laps our planet every 780 days. On Tuesday of next week, Mars will reach what astronomers call "opposition" as Earth overtakes it in its orbit, although it is actually closest to Earth six days later. At opposition means that the object - in this case, Mars - along with Earth and the sun are 180 degrees apart in the sky, so the object rises as the sun sets. While it will be even closer in 2018, this is the closest to Earth it has been since 2003, when Mars came within 58 million kilometres of our planet. To the naked eye, Mars will be very bright and noticeably reddish in colour, and at the moment can be seen in the northeast of our sky at mid-evening. Its distinctive dark markings, viewable through a good telescope, have been noted for centuries, but it has only been in the last 40 years that they have been understood as sporadic global dust storms and seasonal changes in polar ice coverage. "Although tiny Mars is at its closest, a clear view even with a good sized telescope can be rather difficult," said Stardome astronomy educator David Britten. "A steady tripod is essential, and you need to be patient and wait for the local cloud and atmospheric conditions to settle. "The surface is clear at present, but there could be a massive Martian dust storm that clouds the atmosphere and blocks the view of the entire surface for months."
This year brings us two lunar eclipses, the first at a family-friendly time on April 15, the second shortly before midnight in October. This month's eclipse will be special because it starts soon after the sun sets, and from a high vantage point looking east, spectators will be able to see the moon rise from 6pm and move within the Earth's shadow to be completely eclipsed by 7.08pm. Andrew Buckingham of the Auckland Astronomy Society said that the moon would appear a blood red. This was because light from the sun was being reflected off the Earth on to it, creating a reddish colour that can often be seen at sunset or sunrise. At that point, the eclipse would be at "totality", when the moon will be 15 degrees above a flat horizon, but less if there are hills.
By 7.46pm, the moon will be at maximum eclipse, and when totality ends at 8.23pm the moon will be sitting 30 degrees above the eastern horizon. Mr Britten said watching the full moon rising darker and darker, rather than the usual large bright disc, would feel quite strange. "To see the moon disappear during the eclipse, all you need is a good view of the eastern horizon." By 9.32pm, the moon will be completely out of the Earth's umbra (full) shadow, and will appear slightly dim because it will still be within the penumbral shadow until 10.36pm, when the eclipse finally ends. Mr Buckingham said while lunar eclipses were not uncommon, this month's event would be special as it came at a time of year and night when we could all appreciate it. "It's April, so it will be warm enough to go down to the beach with a picnic and watch it happen." Members of the society will be gathering at Browns Bay, Cheltenham Beach, Eastern Beach, One Tree Hill and the Arataki Visitors Centre in the Waitakere Ranges. "People are welcome to join us, but anywhere you can get up a high hill or out to an eastern beach with a clear view across ocean is the place to be."
First human in space
For space enthusiasts keen for more than just an overhead spectacle, Stardome is celebrating the anniversary of the first time a human journeyed into outer space. On April 12, 1961, at the height of the space race between the United States and the Soviet Union, Russian cosmonaut Yuri Gagarin completed an orbit of the Earth in the Vostok 3KA spacecraft. The date - on which Nasa also launched its space shuttle Columbia in 1981 - is named the "International Day of Human Space Flight" and "Yuri's Night", celebrated by space lovers each year. Stardome is marking the night by screening a special planetarium show about the Google Lunar XPRIZE, Back to the Moon for Good
, and a presentation on Gagarin. "It is interesting that the first man in outer space was selected based on his ancestry, and stature - there was no room in the space craft for someone of large build," Mr Britten said. "Gagarin [who was 1.57m tall] orbited Earth once, which took just 108 minutes, but his legacy of adventure and bravery is still celebrated today." Tickets can be booked online at www.stardome.org.nz