You may have noticed that the Edith Winstone Blackwell Zeiss telescope is out of operation for a few weeks. Over the weekend, the mirrors were carefully removed and sent away to be resurfaced to restore them to optimal reflectiveness. The very delicate reflective coating is aluminium deposited as a vapour in a vacuum chamber. It is only a few atoms thick, but when fresh reflects about 92% of incident light.

The telescope tube weighs about 500kg; thankfully, so does the counterweight. The total weight of the telescope and mounting from the top of the concrete pier is 2,300kg. The mount stands on a massive concrete pier beneath the floor that has three legs that go a further 6m down to solid rock (volcanic lava). While the mirrors are removed, the counterweight is propped up, a critical measure to ensure it doesn’t cause extensive damage! The mirrors are carefully removed, packaged up and sent away to Wellington for the resurfacing process.

The Edith Winstone Blackwell 0.5m Zeiss Telescope is our most powerful telescope available for public viewing. It is in a dome which opens up to the night sky. The main eyepiece used in the Zeiss gives a magnification of about 208 times. Manufactured by Carl Zeiss of Jena, East Germany, the Edith Winstone Blackwell Zeiss Telescope was installed at the Auckland Observatory in early 1967, and is one of only 20 such telescopes built.

Telescope Type: Cassegrain
Diameter of Primary Mirror: 0.5m
Effective Focal Length: 6.65m (focal ratio F13.3)

The Zeiss will be back in business in a few weeks. It will be back in business from March 17,  so if you’re coming along to a Night Sky show on a Thursday, Friday or Saturday night, book yourself in for the Zeiss experience. Led by one of our fantastic volunteers, you’ll get a special tour of the visible astronomical wonders- book a spot here.