Constellations of All Sizes
While more inconspicuous autumn constellations take hold in the southern sky, the Summer Triangle is still high in the west.
One of the distinguishing features of Summer is the extended triangle of Vega (Alpha Lyrae) in Lyra, Deneb (Alpha Cygni) in Swan, and Atair (Alpha Aquilae) in Eagle. This month it is still found high in the west on our general map, giving us enough time to view three small but subtle constellations in and around it before they set during the night. The Arrow ("Sagitta", Sge) and the fox ("Vulpecula") lie mostly within the Summer Triangle.
On our overview map you will only find the arrow because the fox does not contain sufficiently bright stars and is therefore not shown. However, in the small constellation is one of the most interesting objects from the Messier catalogue: M 27. It is a planetary nebula like M 57, the Ring Nebula in Lyra. This is a cloud expelled by an aging star that subsequently shrank into a white dwarf. However, he sees fully
different than the Circular Ring Nebula. M 27 was given the name Dumbbell Nebula more than a hundred years ago. It owes its name to its shape, which actually resembles old dumbbells from the 19th century. At that time they consisted of two bells joined at the top without a clapper.
Another tiny constellation just outside the Summer Triangle is the Dolphin ("Delphinus"). With a little imagination, you really recognize a jumping marine mammal in this group. Much further south is the large but inconspicuous ibex ("Capricornus"), which according to legend is actually a sea goat. The front part of this mythical creature comes from a goat, but the rear part from a fish. However, should you identify even one of the two animals in the constellation, you could be hallucinating. The arrangement of the stars reminds me more of a rounded boat.
Alpha Capricorni is a beautiful double star that you can separate with the naked eye if you have good visual acuity. Beta Capricorni is also a double star, but you can only see this with binoculars or a telescope. Farther east on the ecliptic, i.e. to the left of Capricorn, is the faint but elongated Aquarius ("Aquarius", Aqr). However, its stars do not form a memorable figure, let alone a man. After all, he has at least one distinctive arrangement of five stars, which is also called a pitcher.
If you haven't spotted the constellation in the sky yet, associate Deneb with bright star Fomalhaut (Alpha Piscis Austrini, 1st mag) deep in the south-southeast on our survey star map. Aquarius lies right between the two. Fomalhaut can be found by extending the western edge of the Pegasus Square well down.
Planets in October
Jupiter is deep in the southwest. At the beginning of the month it is still clearly visible, but towards the end it sinks earlier and earlier into the haze of the horizon. Mercury shows up below Jupiter in the second half of October. Without binoculars, it might be difficult to spot it at dusk. Saturn rises at around 2 a.m. at the beginning of the month and appears just after midnight towards the end of the month it is very high and only a few atmospheric disturbances distort the picture. He is then in the east-southeast, right above Regulus.
Mars and Venus are both hiding in the bright daylight of the sun. On the night of October 6th to 7th there is a full moon. It is the first since the equinox, which was 14 days ago. The waning Moon will be close to Saturn at dawn on October 17th. At sunset on the 25th there is a thin crescent low in the southwest near Antares, a little to the left of Jupiter and Mercury - not an easy target as the horizon haze makes observation difficult. © astronomy today