Spending A Night With The Stars – the Ideal Christmas Gift

November 24, 2009 by admin · Leave a Comment
Filed under: Refractor Telescopes

The ideal Christmas present for any astronomers in the family is spending a night with the stars looking through the Britain’s largest refractor telescope at the Royal Observatory.

Places are limited for this special treat observing double stars and star clusters with a professional astronomer on nine dates in December using the observatory’s 28” refractor telescope – that ranks as the seventh largest in the world.

These sky watches are only available in the lead up to the winter solstice because they are the shortest and darkest days of the year and often have clear skies due to the colder weather.

Completed in 1893, it was designed to keep the Royal Observatory at the forefront of contemporary astronomy at the start of the 20th century.

Astronomers utilised the telescope for research in to double star systems until its retirement in the late 1960s. It is now a central part of educational programmes at the Royal Observatory. A computer-aided guidance system and CCD camera have3 recently been added to the set up.

Cannonball bearings for rotating mount

Not only is the view of the night sky spectacular from the telescope, but the setting at the observatory in Greenwich, London, is also fascination as the telescope is now housed in an ‘onion dome’ resembling the Taj Mahal in India.

The dome’s shape was a solution to a design problem. The smaller predecessor to the 28-inch telescope had been housed in a flat-topped wooden ‘drum’ mounted on cannonballs which acted as ball bearings.

As the new 28-inch was eight feet longer than the previous telescope, a new dome was needed to avoid major rebuilding of the supporting brick tower. The answer was the 'onion dome', which bulges to a maximum radius of about five feet wider than the supporting tower walls. The cannonballs were also replaced with a more modern system.

Water powered drive froze in winter

The 28-inch lens weighs 200lbs and only two glassmakers in the world were capable of producing it, Commission to completion took eight years.

The telescope sits on an English Equatorial mount made for another telescope that was in use 30 years before the current refractor was built. The original drive was falling water that froze in the winter. Now the telescope is electric powered.

* Booking is required for the star nights by calling the Royal Observatory (020 8312 6608) for dates and availability. Tickets are £5 with concessions at £3.50.