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Places · Ground station
Jet Propulsion Laboratory
Builds and operates the robotic missions: the Mars rovers, both Voyagers, Cassini, Europa Clipper. The Deep Space Network is run from here too.
- Where
- Pasadena, California
- Coordinates
- 34.20°N 118.17°W
- Since
- 1936
- On the map
- Show me
- More
- jpl.nasa.gov
The sky from here
This is a zone 6 sky — bright suburban on the nine-grade scale, Bortle 6–7, reaching roughly magnitude 4.7–5.5 unaided. The sky within thirty degrees of the horizon glows greyish white. Only the brighter constellations survive.
That grade puts 37 of the catalogue within easy reach of 10×50 binoculars and 37 within a 130mm — 9 of them need no instrument at all. Genuinely dark sky — zone 2 or darker — starts about 134 km south-west.
There is no season here in which the sky fails to get properly dark — the Sun clears eighteen degrees below the horizon on all 365 nights.
The centre of the galaxy reaches 27° at its highest, which puts the brightest part of the Milky Way clear of the horizon murk without ever being overhead. Of the 110 Messier objects, 5 never set from here and every one of them rises at some point in the year.
Of everything in the catalogue, Ring Nebula, Hercules Cluster and Triangulum Galaxy are the best served here, climbing to within a few degrees of straight up — 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.
Bode's Galaxy and Cigar 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 34.20°N 118.17°W. Darkness is estimated rather than measured; everything else follows from the latitude and holds along the whole parallel. How accurate this is.
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Questions
What part of the sky never rises at Jet Propulsion Laboratory?
Everything south of declination −56°. From 34.2°N that is a cap 34° in radius centred on the south celestial pole, which is 8.6% of the whole celestial sphere. It is out of reach permanently rather than seasonally: no time of year and no instrument brings it above the horizon. The matching 8.6% around the north celestial pole is the same geometry inverted, and never sets.
How many hours of true darkness does Jet Propulsion Laboratory get?
11 hours 8 minutes on the best night, around 21 December, falling to 6 hours 3 minutes around 21 June. That counts only proper astronomical night, with the Sun eighteen degrees down; the merely-dark hours either side of it are longer. Every night of the year gets there eventually, which is the quiet advantage of not being any further from the equator than this.
When is the Milky Way best from Jet Propulsion Laboratory?
Around 17 June, when the galactic centre transits at local midnight, and usefully from about May to September — earlier each evening as the season goes on. 34.2°N is close enough to the equator that the sky reaches full astronomical darkness on every night of the year, so unlike sites further north there is no part of the season where the core is high and the sky refuses to cooperate.
How far is Jet Propulsion Laboratory from the other sites on this map?
Mount Wilson Observatory is the nearest thing to it here — 11 km to the east. The nearest other ground station is Goldstone Deep Space Complex, 180 km to the north-east. These are straight-line distances over the surface, not driving distances, and in this part of the world the two can differ considerably.