Heavenly light and darkness on Öland

Öland is an island in the south-western part of the Baltic Sea, a 150 km long and 35 km wide island, 7-15 km outside the south-eastern Swedish coast. Since we have a bridge to our island, according to EU we do not have island status. But still, we’re are an island, with 23.000 souls and far more livestock, mainly sheep and cattle. Often grazing on the steppe-like “Alvar”, covering a lot of the inner of the island. A flat, treeless plain. Creating the island’s open sky with its special island light; sunlight during day or full moon over open countryside at night. A three-dimensional experience, that can give an existential feeling, having a lot of artists coming here to paint it.

Sometimes the sky is covered with clouds, but often the skies proves themselves from their best side. Especially between August and October or mid-March to early May, when clear nights are more common than during the rest of the astro year and shows the sky in all its dark splendor. Öland often during the first three months shows some 10 to 15 clear nights per month and the latter some 5-10 nights per month, which is a lot and a premium for us in GAF. Unfortunately June 1 to Aug 1 is a no-astro period for us, to much midnight sunshine.

For the amateur astronomer or the astronomical interested, it is the moon free nights that is the price. Getting to see the Milky Way in all its splendor., with very little ambient light around.

Even if you do not see much more than the intense white band of stars with the naked eye, with only some binoculars as help, night sky give us an entirely new perspective, of what is above us. The moon with its craters, mountains and valleys, the mountain range, Appenines, with Mons Huygens, +5000 m.

The late summer belongs to the constellations of Lyra, the Swan and the Eagle. With their strong stars, Vega, Deneb and Altair, characteristically forming “Summer Triangle” pointing down towards southern horizon, toward the constellation Sagittarius. Seen only a couple of weeks around Aug 20:th, it is the telltale to when GAF holds our yearly star party, aptly named Sagittarius, for members of Swedish Amateur Astronomical Guild, SAAF.

Around the Öland Harvest Festival, end September/October 1, is the time for Andromeda, M31, and the Triangulum (M33) galaxies to show up. Most people with good vision can a dark evening, out on the Alvar, see M31 as a “dew cloud” at Andromeda’s top edge. Thats how many club members evaluate the astro evening’s good or bad “seeing”. M33, for its part, requires a really, really clear and dark night, at one of our +22 SQM sites, and perfect (20/20) vision. But if so, it is visible from our island. That is about how far you can see from Öland, at least without binoculars or telescopes.

This darkness, the often good seeing and the normally good visiting services (mid- winter we’re more like a bear, hibernating 😉 , we are not picky, we like to share information of our Island of whcih we asre proud. Therefore we have published a visitors guide where to find good and relatively dark spots (SQM values 20-22) easy accessible for visitors with a car/camper wan. We also have more comprehensive measurements uploaded to the “light pollution map” available from our web page and also through the links below.

Lightpollution map

If you have questions about GAF and our island, just contact us via our contact form on the web site.