July Sky and Space Station(s)
By Chuck McPartlin
On Monday, July 5, we are at aphelion, our most distant from the Sun for the year, about 3.4% farther away than we were at perihelion in January.
At sunset on Monday, July 12, catch Venus and Mars only half a degree apart low in the western sky, with a thin crescent Moon to their upper left.
Look with binoculars or a telescope along the Moon's day/night terminator on Friday, July 16, between 3 PM and 5:30 PM PDT to see the Lunar X formed by illuminated crater rims peeking out of the darkness.
The International Space Station will be making some visible passes through our evening skies during July. It will also be appearing in the predawn sky, and its orbit may change from time to time, so to get the latest and most complete predictions, visit Heavens Above.
You can also get predictions for the new Chinese space station, Tianhe-1. It is much smaller and dimmer than the ISS, but I've included its three brightest passes.
On Saturday, July 3, Tianhe-1 will rise at 9:14 PM PDT in the WSW, and pass overhead from Crater, through Virgo and Hercules, and bisect the Summer Triangle to set in the ENE at 9:20 PM.
On Monday, July 12, the ISS will make two passes, starting at 8:47 PM in the SSE, going low through the stinger of Scorpius to below the Summer Triangle in the E at 8:51 PM. On its next orbit, it will appear at 10:22 PM in the WSW, starting in Corvus, then between Leo and Virgo, the handle of the Big Dipper, above Polaris, and setting in the NE, in Cassiopeia, at 10:29 PM.
Tuesday's first pass of the station will start in the SW in Corvus at 9:35 PM, and pass overhead by Spica, the head of Draco, and then set in the NE at 9:41 PM. This is the brightest pass of this sequence. It will show up again briefly at 11:14 PM very low in the NW.
On Wednesday, the ISS will once again make two passes, beginning at 8:48 PM in the SSW in Centaurus, sailing through the head of Scorpius, Ophiuchus, and the Summer Triangle to end in the ENE at 8:54 PM. At 9:18 PM, Tianhe-1 will show up in the WNW at 9:18 PM, going by the junction of the bowl and handle of the Big Dipper, then by Vega and Altair along the top edge of the Summer Triangle to the ESE, where it will fade away at 9:23 PM. Then the ISS will skim low over our mountain horizon from the WNW to the NNE between 10:26 PM and 10:30 PM.
Thursday's pass will be a higher version of Wednesday's second pass, starting at 9:38 PM in the W, visiting Leo, the forebody of Ursa Major, and Cassiopeia, where it will disappear at 9:43 PM in the NNE.
On Friday, it will rise at 8:50 PM in the WSW, going a bit higher through the hindquarters of Leo, the bowl of the Big Dipper, just above Polaris, and setting in the NE in Cepheus at 8:56 PM. It will be joined by Tianhe-1, which rises at 8:52 PM in the WNW in Leo, cruises by Mars and bright Venus, then near orange Arcturus and through Ophiuchus to set in Sagittarius at 8:57 PM in the SE. It'll take some effort to watch them both at once!
Saturday, July 17, the ISS will appear in the NW at 9:42 PM for a brief mountain horizon skim ending in the N at 9:44 PM.
On Sunday, the station will repeat a higher version of that trajectory, rising at 8:53 PM in the WNW by Mars and Venus, and setting at 8:57 PM in the NNE in Cassiopeia.
The ISS will be absent from our evening skies for a week, and return for a series of brief and low appearances late in the evenings along our mountain horizon from July 25 to July 30. It will end July with a bright pop-up on July 31, starting in the NW at 9:59 PM in the legs of Ursa Major, and climbing to the middle of Draco, where it will fade into our shadow in the NNW at 10:02 PM.