Saturday: The
Southern Delta Aquarid meteor shower peaks this week and on into mid-August.
Meteor showers are named after the constellation from which the meteors appear
to originate. These meteors appear to come from a point in Aquarius near the
star Delta Aquarii, also known as Skat. This point is about one and a half
fists held upright and at arm’s length above the southeastern horizon at 1 am
tonight. You can follow this point throughout the night, as it will remain a
fist above Fomalhaut, the brightest star in that section of the sky. Since the
New Moon is this week, the skys will be exceptionally dark during prime meteor
watching time. For more information about this year’s shower, go to https://earthsky.org/?p=159138. As your
Mother might say, dress warm and sit in a comfortable chair for maximum
enjoyment. Meteors are tiny rocks that hit the Earth and burn up in the
atmosphere.
Sunday: Aldebaran
and the Hyades Cluster are one fist to the upper right of the Moon at 5 a.m.
Monday: Mizar is a
well-known binary star in the constellation Ursa Major. You can find it at the
bend in the Big Dipper handle, five fists above the west-northwestern horizon
at 10 p.m. Its name is Arabic for waistband. Mizar has an optical double called
Alcor, which is less than a pinky width away and can easily be seen with the
naked eye. Optical doubles are stars that are close together in the sky but do
not orbit a common center of mass as true binary stars. Not wanting to deceive
sky gazers who call Alcor and Mizar a binary star, two stars that DO orbit a
common center of mass, Mizar actually is a binary. It was the first binary star
system discovered by telescope. Mizar A and Mizar B are about 400 astronomical
units apart from each other and about 80 light years from Earth. 400
astronomical units is about 10 times the distance between the Sun and Pluto.
Tuesday: Jupiter is
two fists above the southern horizon and Saturn is a little less than two fists
above the south-southwestern horizon at 10 p.m.
Wednesday: What you
see with the naked eye isn’t all that can be seen. While astronomers can learn
a lot from observing the sky in the visible wavelengths, many celestial objects
radiate more light, and more information, in wavelengths such as radio,
microwave, infrared, ultraviolet, x-ray, and gamma ray. In 2012, NASA launched
the Wide-field Infrared Survey Explorer (WISE) to study objects that radiate in
the infrared range such as asteroids, cool dim stars, and luminous galaxies. For
an interesting comparison of how different wavelengths show different aspects
of celestial objects, go to http://goo.gl/nvuax. For example, if it weren’t for
infrared telescopes such as WISE, astronomers would not know about the
significant amount of dust in galaxies. We also wouldn’t know how much
brighter than the Sun red supergiant stars are. Antares is a red supergiant
star, currently sitting at one and a half fists above the south-southwestern
horizon and one fist to the lower right of the much brighter (and much closer)
Jupiter. In the visible wavelengths, Antares shines 10,000 times brighter than
the Sun. But since Antares is much cooler that the Sun, its energy distribution
peaks in the infrared. So across all wavelengths of light, Antares shines 60,000
times brighter than the Sun.
Thursday: The
planet Mercury is less than a half a fist above the east-northeastern horizon
at 5 a.m., just ahead of the rising Sun. It is about a fist to the lower right
of the Gemini twin stars, Pollux and Castor.
Friday: It is not
winter yet. But Orion, thought of as a winter constellation, is just above the
east-southeastern horizon at 5 a.m. By the actual winter, it will be visible in
the evening sky.
The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm.
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