July/August 2014 Sky Watcher’s Guide

This will be an every-two-months guide to what you can see in the night sky, geared to mid-latitude northern hemisphere observers. The original post with more detailed guidance can be found here. What can you expect to see in July and August 2014?

JULY, 2014

Moon Phases: Full on July 12th; new on July 26th. On the 26th, the Moon passes almost five degrees south of the Sun, which is about as far away from the Sun as it can get. It does this because the orbit of the Moon around the Earth does not precisely align with the orbit of the Earth around the Sun. They are actually tilted about five degrees (of course) away from each other. The Earth’s orbit defines the plane of the ecliptic.

Last year the first photograph of the Moon taken at the exact instant of its new phase was taken at a similar moment.

You can’t get a thinner sliver of moon! What you are seeing is actually just sunlit mountains along the moon’s limb.

Planets: Now is the time to see Mars and Saturn while you still can. Both appear in the southern sky, but Mars is farther along and sets earlier. By the end of the month however, Saturn will set before midnight.

Meteor Showers: Nothing too exciting this month for Northern Hemisphere observers.

Deep Sky: Around the time of new moon, make arrangements to be somewhere far from city lights, with an unobstructed view to the southern horizon. This is the time of year when the center of the Milky Way, our galactic home, is most easily visible. It’s low on the horizon for those of us in the north, which provides an excellent rationale for a trip to the Southern Hemisphere that will put it overhead! But I digress.

The center of the Milky Way is in the constellation of Sagittarius, whose teapot-shaped asterism makes it easy to find low in the south. The exact center is shown in this image.

At the center, as there is at the center of most galaxies, is a supermassive black hole.  We don’t “see” a black hole—by definition it absorbs rather than emits light—but we can infer its presence by its effects on nearby objects. Here is a diagram that shows stellar orbits near our galactic center.  The stationary image shows the view from our perspective.

The image is small, but the 3-D rotation should convince you that there is something quite massive at the center—and that is the black hole.

Sky Charts:

Looking south, 10 pm, July 15th.

2014 July South Sky

Looking north, 10 pm, July 15th.

2014 July North Sky

Southern-facing view in chart form.

2014 July South Chart

Northern-facing view in chart form.

2014 July North Chart

AUGUST, 2014

Moon Phases: Full on August 10th; new on August 25th. In the summer, full moons are lower in the sky (more southerly) and the Sun is higher (more northerly). In the winter this is reversed: full moons are high on winter nights and the Sun is low during a winter day. All of this is from a northern hemisphere perspective.

Planets: Mars and Saturn are already low in the west by the time of full dark; you’ll need to catch them early in the evening.

Venus is still the bright “morning star”, but it rises a little later each day as it moves closer to the Sun in our sky.

Meteor Showers: Probably the most famous meteor shower of all takes place in August. Although it peaks on the night of August 12-13, Perseid meteors can be seen for a few nights both before and after this peak. This year the moon will prevent your seeing the dimmest of these—it is just past full–but you should still be able to see plenty of meteors, perhaps as many as one every minute or so. The best viewing time is in the early morning hours between midnight and dawn. Lie flat on a blanket or a lawn chair and look up. You don’t really need to look in any particular direction.

Deep Sky: If you are willing to stay up a little later, the most distant object visible to the naked eye can be your reward. To the northeast, the Andromeda Galaxy (also known as M 31) has already risen at 10 pm in the middle of the month, and will rise further as the night progresses. A better time will be later in the month when the moon will not interfere and M 31 will rise earlier in the evening. At new moon on the 25th, it will be at an altitude of around 45 degrees (halfway to the zenith) at midnight, and at its highest point around 4 am. The Andromeda Galaxy is the nearest spiral galaxy to our similar Milky Way, 2.5 million light years away. To the naked eye, it is a noticeable fuzzy patch of light as in the center of this image.

In binoculars, the densely packed central nebula is visible, along with some of the spiral structure if the skies are dark.

In telescopic photos its full extent is revealed.

Its apparent size is actually wider than the full moon as seen from Earth, but of course it is too dim to be seen as in the image below.

Sky Charts:

Looking south, 10 pm, August 15th.

2014 August South Sky

Looking north, 10 pm, August 15th.

2014 August North Sky

Southern-facing view in chart form.

2014 August South Chart

Northern-facing view in chart form.

2014 August North Chart

 

Posted in Sky Phenomena

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