Places · Observatory
Effelsberg 100-m Radio Telescope
Sited in a valley that shields it from terrestrial radio noise, and a regular station in the global VLBI networks that imaged a black hole shadow.
- Where
- North Rhine-Westphalia, Germany
- Coordinates
- 50.52°N 6.88°E
- Since
- 1972
- On the map
- Show me
The sky from here
Measured at these coordinates the sky is zone 5: suburban, which is Bortle 5–6 and a naked-eye limit of about magnitude 5.2–6.0. The Milky Way is invisible or nearly so. Clouds are lit from below. You can read a newspaper outside on a clear night.
Of the 110 Messier objects, 15 are an unaided-eye target from a sky this dark, 82 are comfortable in 10×50s and 85 in a 130mm reflector. You would have to get roughly 329 km north-west before the sky reaches Bortle 2.
For 48 nights of the year — 29 May to 15 July — the sky here never reaches astronomical darkness, because the Sun stays within eighteen degrees of the horizon all night. Distance from the nearest town makes no difference to that.
The galactic centre tops out at 10° from this latitude — low enough that the busiest part of the Milky Way is always behind the most atmosphere, which is what separates this sky from a southern one. Of the 110 Messier objects, 21 never set from here and every one of them rises at some point in the year.
Owl Nebula, Spindle Galaxy and Sunflower Galaxy pass close to the zenith from this latitude — an object at the zenith is being seen through the least air it will ever be seen through, and the difference against the same object low in the south is not subtle.
Little Dumbbell, Whirlpool Galaxy and Pinwheel Galaxy never set from this latitude, so they are available on any clear night of the year rather than for one season of it.
Read at 50.52°N 6.88°E. Darkness is estimated rather than measured; everything else follows from the latitude and holds along the whole parallel. How accurate this is.
Nearby
Questions
What part of the sky never rises at Effelsberg 100-m Radio Telescope?
Everything south of declination −39°. From 50.5°N that is a cap 51° in radius centred on the south celestial pole, which is 18% of the whole celestial sphere. Nothing about the calendar or the aperture changes that — the cap is below the horizon at every hour of every night. Its mirror image, the same 18% around the north celestial pole, is circumpolar here and never goes down.
How many hours of true darkness does Effelsberg 100-m Radio Telescope get?
Anything from 11 hours 58 minutes down to none whatsoever. Around 21 December the night is as long as it gets here, and around 29 May the sky simply never finishes darkening — a problem no amount of driving solves, because it is the Sun's depression angle and not the streetlights. That counts only proper astronomical night, with the Sun eighteen degrees down; the merely-dark hours either side of it are longer.
When is the Milky Way best from Effelsberg 100-m Radio Telescope?
Not when it is highest, which is the frustration of observing from 50.5°N. Mid-June puts the galactic centre on the meridian at midnight and also falls inside the weeks when this latitude has no true darkness, so the two best things about summer cancel each other out. The answer in practice is late August, with the core lower in the south but a genuinely dark sky behind it.
How far is Effelsberg 100-m Radio Telescope from the other sites on this map?
The nearest is ESOC — European Space Operations Centre, about 144 km to the south-east. The nearest other observatory is Jodrell Bank — the Lovell Telescope, 698 km to the north-west. These are straight-line distances over the surface, not driving distances, and in this part of the world the two can differ considerably.