Galilean moon mutual events

Galilean Moon

There are some great mutual satellite events between Jupiter’s moons this month. On 6 December between 22:11 UT and 22:19 UT, Ganymede almost totally occults Io. On 12 December, it’s Europa’s turn to pass across Io. Although this isn’t such a complete occultation, both objects...

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The Geminid meteor shower

Geminid Meteor Shower

The Geminid meteor shower arguably puts on the best display of the year, although fans of the Perseids, which peak on 13 August, may disagree. The reason why this split occurs is that the Perseids peak when the nights are shorter and warmer. Mid-December has around 12...

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Lunar libration favours the north polar region

Lunar libration

The moon presents the same face towards Earth throughout the course of the lunar month, by virtue of the fact that it rotates once on its axis for every revolution around our planet. However, the fact that the Moon’s orbit is elliptical means that its orbital speed...

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Starry Night Pro Plus 7

Starry Night Pro Plus 7 Review

Starry Night Pro Plus 7 Review – Planetarium programs help us to make sense of the sky above on any given date, from any location – even from the surfaces of distant worlds. Some are more sophisticated than others, allowing us to explore the bodies...

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Olivon 10×50 QB binoculars

Olivon 10x50 QB binoculars Review

Olivon 10×50 QB binoculars Review – The 10×50 has become a standard for handheld binoculars, offering a good compromise of light-gathering, magnification and weight. Olivon’s 10×50 QBs are also water-resistant, a quality that is highly desirable on a dewy night. These binoculars are supplied with a...

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Celestron Cosmos 90GT

Celestron Cosmos 90GT Review

Celestron Cosmos 90GT Review – Celestron’s Cosmos 90GT is a beginners’ telescope with a twist – there is no handset. That’s because this system is specifically designed with smartphone and tablet users in mind. The scope is supplied with 25mm and 10mm eyepieces, a star diagonal...

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European Extremely Large Telescope (E-ELT)

European Extremely Large Telescope (E-ELT)

Despite downsizing its plans over the past 15 years or so, the European Southern Observatory (ESO) will still be building the largest telescope ever. In the late 1990s, engineers came up with an ambitious proposal for developing the 100m Overwhelmingly Large Telescope, but ESO later committed...

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Giant Magellan Telescope (GMT)

Giant Magellan Telescope

Like The Thirty Meter Telescope and the European Extremely Large Telescope, the international Giant Magellan Telescope will have a segmented mirror. But instead of many hundreds of hexagonal pieces, the GMT’s primary consists of just seven 8.4m mirrors – about the largest that can be cast...

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Thirty Meter Telescope (TMT)

Thirty Meter Telescope

As its name implies, the Thirty Meter Telescope will be outfitted with a 30m mirror. That’s far too big to cast in one piece, so the TMT’s primary consists of 492 hexagonal segments. As such, the TMT can be regarded as a scaled-up version of...

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