Forty-eight years ago on Thursday, the Apollo 11 LEM (Lunar Excursion Module) touched down on the Moon carrying Neil Armstrong and Buzz Aldrin. It was the farthest place humans had ever ventured. This week as you see the Moon in the morning take a moment to remember that historic time. Here is your guide to the sky for July 17 to 23, 2017…
Sun and Moon
The Moon is a waning crescent this week visible in the morning sky, try seeing it on Thursday (July 20) when it makes a brilliant site with Venus before dawn. It is at perigee on Friday and New Moon is on Sunday at 5:46 am finishes out the week. Sunrise this week is at 5:09 am and sunset at 8:14 pm as the Sun passes into the constellation of Cancer the Crab. If you happen to have solar eclipse glasses or a solar filter available, there is a large sunspot visible – just make sure to view it safely!
Planets for the week
Mercury is low in twilight after sunset in the western sky and quite a challenge to spot this week. Brillian Venus is in Taurus and on Thursday will be 3 degrees from a waning crescent Moon rising just after 2:15 am. Jupiter is in the southwest at sunset in Virgo setting just before midnight this week, while the ringed jewel Saturn is visible from sunset until around 3:00 am when it sets in the west. Mars continues to be lost in the glare of the Sun and is not visible this week as it moves toward conjunction with the Sun on July 26th.
Summer Dolphin…What’s in a name?
Last week we followed the Milky Way rising out of Sagittarius (the teapot) up through the Summer Triangle of Vega, Deneb, and Altair. If you can find those three stars, look to the eastern side of the triangle for a faint grouping of stars called Delphinus the Dolphin. While the group is small, it does jump out because the 5 stars are close together. A fun Delphinus story explains the names of its two brightest stars, Sualocin and Rotanev. They are the result of a practical joke by Niccolo Cacciatore who worked at Palermo observatory in Italy in the early 1800’s. While compiling a new edition of the Palermo Star Catalog, he inserted a Latinized version of his name (Nicolaus Venator, meaning Nicolaus Hunter in English) into Delphinus. Sualocin and Rotanev spelled backwards is? You guessed it, Nicolaus Venator! Star names are normally Arabic in origin, so these stick out as a bit out of the ordinary. The constellation itself goes back to the Greeks. Poseidon, god of the sea, built himself a magnificent underwater palace, but for all its opulence it felt empty as he had no wife. Searching for a wife he came across Amphritrite, a sea nymph. She fled from him to hide among the Nereids. Poseidon sent a messenger after her, a dolphin which found her and convinced her to marry the sea god. As a reward, Poseidon placed the image of the dolphin in the stars.
Some bright passes of ISS
Tuesday morning from 1:39 am to 1:43 am catch the International Space Station moving from northwest to northeast. On Wednesday look for it from 3:58 am to 4:04 am moving from northwest to east. On Friday see it from 12:39 am to 12:42 am travelling from north to east, and it’s brightest pass for this week is the same day from 3:50 am to 3:56 am moving from northwest to east-southeast.
Check out the Moon and Venus while remembering human space history on Thursday, check out some bright planets in the evening sky, or see if you can spot that dolphin with the backward astronomer star names. Happy summer stargazing and keep your eye on the sky!