Transit of Mercury

The Blackett Observatory will be open for the Transit of Mercury on Monday 9th May.

The planet Mercury transits across the face of the Sun roughly 12 times a century, whilst not as rare as a Venus transit, it is not always well placed for observation.

Last time it was well viewed from Marlborough was May 2003. This year’s event is well placed as the Sun is high in the sky and the entire transit (7.5 hours) is visible (weather permitting). The next Transit on 11th November 2019 will not be as well situated.

The planet appears only as a tiny black dot against the immensely bright photosphere of the Sun and at no time is it safe to view without professional filters. It is too small for viewing with solar goggles (as used at the March 2015 Eclipse) and even hard to see when projected. The only safe method is through a properly equipped instrument as at the Observatory.

The Observatory will be open from 12 noon till 7.45pm. There will be three instruments in use with professional solar filters. Mid-Transit is at 3.57pm.

The event is open to non-College members and families, though children under 7 years are not recommended.

The Observatory will not be open if it is cloudy. Click here for updates on Monday.

Charlie Barclay
Director of the Blackett Observatory

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