Cosmos Observatory

Two sundials at Cosmos Observatory, near Lattrop

Analemmatic and equatorial sundials in Astro-garden (May 2000)

'Cosmos Observatory', a sturdy name. Much better than "Euregio Public Center for Astronomy", as it used to call itself until recently.

The observatory houses a 40 cm (16") telescope and a planetarium. The "Astro garden" is situated aside from the buildings. It is surrounded by a "Stonehenge Circle". An analemmatic sundial is right in the center, and an exceptional armillary sphere can be seen at right, in front of one of the megaliths.
Additional features are a Planet Trail and a Rainbow Garden. So there is something for everyone.

Website: Cosmos Observatory



Analemmatic summer dial

Some hour points of the analemmatic dial The analemmatic dial has a major axis of 6 meters (20 ft), which goes along fine with a human gnomon. It reads daylight saving time. The hour points are round, concrete plaques with Roman numerals in bronze. The grounds in between are covered with sea shells. That's why contrast is low in the picture at left.


Date line of analemmatic dial

It took me a while to realize what was the matter with the date line. It looks much too short, as you might have noticed already from the picture at the top.
The answer: it is just the summer half of the date line. Quite clever, actually: few visitors will dwell here in winter. And that's why it is reading daylight saving time. In addition, the treasurer loves it. The date line indicates the zodiacal months.


Location: 52.4° N, 7.0° E
Design: B.P.U. Holman
Inauguration: ?



Armillary sphere with corrector

Half-open armillary sphere

The half-open armillary sphere has a diameter of about 90 cm (36") and is crowned by a rising Phoenix.
The dial has two time rings. Apparent local time is read from the lower ring, civil time from the upper one.

Civil time is obtained by a corrector, which takes care of the equation of time. It is a plate that can rotate around the pole-style. It has to be reversed each half year. The corrector has to be aimed at the sun by minimizing the shadow of the small stub (as is done below at left). Time is then read at the right-hand edge of the shadow.

Corrector for the equation of time Accurate to the minute...

The reading is said to be accurate to the minute. Well, let's check that. My watch reads 14:48, the dial 13:47. Daylight saving time has been introduced in the Netherlands only in 1977; the dial is older. Aside from that hour, the difference is one minute. Afterwards I checked my watch against the radio beeps, and guess what? It was one minute fast!


Location: 52.4° N, 7.0° E
Design: J.N.A. Gerard



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