Night Sky Highlights for October-December 2019
Solar System
Transit of Mercury
November 11
This fairly rare event occurs only about 13 time a century. If we have clear skies, this transit will be nicely placed for observers throughout the eastern US. Using a proper solar filter or eyepiece projection is essential for your safety! With proper precautions, you can see Mercury as a small round ball slowly crossing the disk of the Sun.
Here are the times of the main events (EST):
First contact: 7:35 am
Mid-transit: 10:19 am
Last contact: 1:04 pm
Mercury
In addition to its transit across the Sun in November, you can spot Mercury low in the west right after sunset during mid-October. It reaches it greatest eastern elongation (when it is farthest from the Sun) on October 20.
Venus
Venus can be spotted low in the western sky after sunset, passing by Jupiter and Saturn at different times. It will pass by Jupiter on November 24 (though the two planets will be very low in the sky), and it will be 2 degrees south of Saturn on December 11. Venus will appear much brighter than either Jupiter or Saturn, but if you look through a telescope it will have a much smaller disk (just 10 to 12 arcseconds in diameter).
Mars
In mid-October, the red planet starts to appear in the eastern sky before dawn. It gets higher in the eastern sky as we move into November and December, but it is still very far from the Earth, and its disk will appear very tiny through a telescope, even with high magnification.
Jupiter
Look for Jupiter early in the fall while it is still visible. It will be in the southwest after sunset on October evenings. It is moving toward the Sun, and by the end of November it will be too low in the evening twilight to see.
Saturn
Through October and November, you can spot Saturn in the western part of Sagittarius. Besides observing its rings through a telescope, see if you can spot a few of its moons nearby. By December it will be so low in the west after sunset that it will be hard to spot.
Uranus and Neptune
Autumn is the best time of year to look for these two gas giants. (In fact, this will be true for many years to come because the positions of these distant planets change very slowly from year to year.) Uranus is in Aries and Neptune is in Aquarius. Both can be seen in even the smallest of telescopes if you take the time to find them. You will need a finder chart such as the one in this article from the Sky & Telescope website:
www.skyandtelescope.com/observing/planets/ice-giants-neptune-and-uranus/
Deep Sky Objects
Many deep-sky objects can be exciting targets to find on a crisp, clear fall evening. Here is just a small sample, ranging from a nearby double star to very distant galaxies. If you need directions, the online version of this newsletter has links to get printable star-hop charts for these objects.
Eta Cassiopeiae (Achird)
Double star in Cassiopeia
This is one of the easiest double stars in the sky to locate because it is the “sixth star” of the W-shape of Cassiopeia, near the second bend in the W. It is one of the nearest stars, just 19.4 light years away, and the brighter component is about the same size and brightness as our Sun. Look for the contrasting colors in this pretty pair. Star-hop chart
Messier 103
Open cluster in Cassiopeia
This cluster is easy to find near the first bend in the W-shape of Cassiopeia. It is a small but distinct cluster with a triangular shape. Star-hop chart
Messier 29
Open cluster in Cygnus
This is a small cluster of a few dozen stars that is just a few degrees away from the central star in the cross shape of Cygnus. Star-hop chart
Messier 39
Open cluster in Cygnus
This is a large and loosely structured open cluster that can be easily seen in binoculars and is a nice target for a telescope with a wide-field eyepiece. Star-hop chart
NGC 7009, the Saturn Nebula (Caldwell 55)
Planetary nebula in Aquarius
This unique planetary nebula has two thin projections that make it resemble the planet Saturn, although it has a blue-green color. At magnitude 7.8, it can be seen in even small telescopes. It is estimated to be about 3000 light years away. Star-hop chart
Messier 76, the Little Dumbbell Nebula
Planetary nebula in Perseus
This planetary can be seen as a rectangular patch in a low-power eyepiece, but with a larger scope and higher power its two lobes can be seen, and its shape is somewhat similar to the much larger dumbbell nebula (M27). Star-hop chart
NGC 457, the Owl Cluster (Caldwell 13)
Open cluster in Cassiopeia
This is also known as the ET cluster. Looking through a low-power eyepiece, the observer can imagine either an owl shape with two bright eyes and outstretched wings, or the character ET from the movie. It is about 7,900 light years away. Star-hop chart
NGC 253, the Silver Coin Galaxy (Caldwell 65)
Galaxy in Sculptor
Because it is relatively nearby (9.8 million light years), this galaxy appears very large through a telescope, and it would probably receive much more attention except that it is found fairly low in the sky at mid-northern latitudes. It is the largest member of the Sculptor group of galaxies, the closest group to our own Local Group. Through a large telescope on a dark night it shows a lot of internal structure, and the entire galaxy has a mottled appearance.
NGC 7331 (Caldwell 30)
Galaxy in Pegasus
About 47 million light years away, this fairly bright spiral is magnitude 9.3, and offers a good target for any telescope. Larger scopes will show some structure in its oblong shape. There are four smaller and dimmer galaxies just to the east of NGC 7331 that may be seen with medium to large scopes. Star-hop chart
Perseus I
Galaxy cluster in Perseus
If you want to look very deep into the universe, try spotting the brighter members of this galaxy cluster. The group is 240 million light years away, making it one of the most distant galaxy clusters that can be observed through typical amateur telescopes. Two of its brightest members are galaxies NGC 1272 and 1275 (both around magnitude 11.9). Other dimmer galaxies can be also spotted in medium to large scopes. Star-hop chart