Time-lapse image of the Meteor Outburst which occurred during the annual Perseid Meteor Shower in 2009. (Image Source: NASA / Jet Propulsion Laboratory)
By Glenn A. Walsh
Reporting for SpaceWatchtower
During tonight's
peak of the annual Perseid Meteor Shower, NASA is predicting a
possible “Meteor Outburst,” when 150-to-200 meteors per-hour
might be visible under ideal conditions. Internet web-casts of
this Shower / “Outburst” are available (Internet links to these web-casts are listed at the end of this blog-post), for areas which
experience cloudy weather. This comes 150 years from the time that
famous Italian astronomer Giovanni Schiaparelli discovered that
comets are the cause of Meteor Showers.
This year's Perseid Meteor Shower and
possible “Meteor Outburst,” which peaks tonight (Thursday Evening
/ Friday Morning), is expected to be one of the best of the last few
years, due to no moon-light obscuring the dimmer meteors after
moon-set. And, before the best viewing time period for the Meteor
Shower / “Outburst,” a conjunction of the Moon, two planets, and
a bright star are prominent.
“Forecasters are predicting a Perseid
outburst this year with double normal rates on the night of Aug.
11-12,” said Bill Cooke with NASA’s Meteoroid Environments Office
in Huntsville, Alabama. “Under perfect conditions, rates could soar
to 200 meteors per hour.”
An “Outburst” is a Meteor Shower
with many more meteors than usual. The last Perseid Outburst occurred
in 2009. The next Perseid Meteor Outburst is expected around 2027.
After evening twilight in the southern
sky on Thursday night, well before the best time to view the Meteor
Shower, the waxing-gibbous Moon can be seen forming a quadrangle or
diamond with the Planets Mars and Saturn, and the bright Star Antares
(the Moon will be a little further to the left on Friday night). At
about an hour after sun-set, Mars, appearing as a small red dot, can
be seen below the Moon. Saturn can be seen to the lower left of the
Moon, and Antares (Alpha Scorpii – the brightest star in the
Constellation Scorpius the Scorpion, as well as the 15th
brightest star in the night sky), also reddish, can be seen below
Saturn and to the left of Mars.
The peak of the Perseid Meteor Shower,
this year, actually occurs Friday Morning, 2016 August 12 at 9:00
a.m. Eastern Daylight Saving Time (EDT) / 13:00 Coordinated Universal
Time (UTC). Since the peak time is closest to the early morning
hours of Thursday Night / Friday Morning, this is considered the very
best time to see Perseids. However, as the early morning hours of
Friday Night / Saturday Morning are less than 24 hours after the
peak, this time period may also feature a good share of Perseid
Meteors.
This year, by around 2:00 local time
both Friday and Saturday mornings, the waxing-gibbous Moon is setting
or has set. The Moon had reached the First Quarter Phase yesterday,
Wednesday Afternoon, 2016 August 10 at 2:21 p.m. EDT / 18:21 UTC.
Bright moon-light, before moon-set, prevents the dimmer Perseid
meteors from being seen. But once the Moon has set, more meteors can
be seen, until astronomical twilight starts interfering with
observing a little before dawn. So, looking for the many dimmer
meteors which may be visible in the Meteor Outburst would be best
after local moon-set.
During the peak time of most normal
Perseid Meteor Showers, often 50 to 80 meteors can be seen per-hour,
if observing conditions are ideal. As previously mentioned,
NASA predicts the hourly rate of meteor visibility could be nearly
doubled during the Meteor Outburst—again, under ideal observing
conditions.
Well, what are ideal or perfect
observing conditions? Ideal Meteor Shower observing conditions
and viewing tips would include ---
Ideal Meteor Shower Observing Conditions & Viewing Tips
- Clear sky – Of course the sky has to be clear, or nearly clear, to be confident of viewing meteors.
- View meteors away from bright lights - As most meteors are often dim, it is best to view a Meteor Shower away from city lights, which cause a brightening of the sky at night, and hence, the dimmest meteors are often missed.
- If possible, wait until after local moon-set – Due to the dark sky, our close Moon looks very bright in that sky, particularly when near the Full Moon phase. This bright light can also drown-out some of the dimmer meteors. So, it is best to wait until after local moon-set for meteor watching.
- Find a good observing site where the entire sky, or nearly the entire sky with a minimum of obstructions, is visible.
- Observe between, approximately, local midnight and local dawn - The best time to watch most Meteor Showers, when most meteors are entering Earth's atmosphere, is usually between local midnight and dawn, when the Earth is rotating into the Meteor Shower.
- Use your own “one-power,” unaided eyes (i.e. naked-eyes) – Use your own eyes to scan the entire sky looking for meteors. Binoculars and telescopes are not very useful for finding meteors. Meteors streak across the sky in a very brief period of time, too short to aim binoculars or a telescope. So, the best way to view a Meteor Shower is to lie on a beach towel or blanket on the ground, or sit in a reclining chair, in an area with a good view of the entire sky (with few obstructions such as buildings, trees or hills), and keep scanning the entire sky.
- Always scan the entire sky for meteors - Meteor Showers appear to emanate from a radiant point in the sky. As an example, for the well-known Perseid Meteor Shower, the radiant appears to be the Constellation Perseus, named for the hero of Greek mythology. However, you should not, necessarily, be looking only at Perseus, when looking for meteors in this shower. Meteors can appear in any part of the sky at any time. In fact, looking towards Perseus may not result in finding the best meteors, as meteors coming from the apparent radiant may be seen for a shorter time in the sky.
- Go out to the night sky early, before you truly start observing, to adapt your eyes to the dark sky - Dark-adapting your eyes for meteor watching could take up to a half-hour.
Now, the information in the previous
eight items are ideal Meteor Shower observing conditions
and viewing tips, which would
most likely result in the maximum meteors than could be observed.
However, even if your conditions can not reach the ideal, so long as
you follow these eight guidelines as close as possible, it is likely
that you will see a fair number of meteors during a typical Meteor
Shower.
Viewers in the Northern Hemisphere are
fortunate that the Perseid Meteor Shower arrives during the Summer
month of August, when temperatures are comfortable for nighttime
viewing. Although, sometimes August can be very humid and muggy with
poor seeing conditions.
A Meteor Shower normally consists of
dust particles related to a comet. Each time a comet approaches the
Sun, the comet loses dust particles following the melting of ice on
the comet. These dust particles, called meteoroids, continue to
follow the same orbit as the comet and form a meteoroid stream. Each
year, as the Earth orbits the Sun, the Earth passes through several
of these meteoroid streams, becoming Earth's Meteor Showers.
The Earth's gravity then attracts many
of these meteoroids to fall to Earth, and they are viewed by people
as meteors, as they burn-up in the atmosphere. Most are extremely
small and burn-up completely. From time-to-time, larger particles
enter the atmosphere and create brilliant displays known as fireballs
or bolides. If these particles are large enough, they may not
completely burn-up and land on Earth as a meteorite.
Most years, Earth might graze the edge
of Comet Swift-Tuttle’s debris stream, the source of this
well-known Meteor Shower, where there is less activity. Occasionally,
though, Jupiter’s gravity tugs the huge network of dust trails
closer, and Earth plows through closer to the middle, where there’s
more material.
This may be one of those years. Experts
at NASA and elsewhere agree that three or more streams are on a
collision course with Earth.
“Here’s something to think about.
The meteors you’ll see this year are from comet flybys that
occurred hundreds if not thousands of years ago,” said NASA's Bill
Cooke. “And they’ve traveled billions of miles before their
kamikaze run into Earth’s atmosphere.”
Meteors can be seen any night of the
year, although they are not predictable and are rare outside of one
of the annual Meteor Showers. The vast majority of meteors that can
be seen during the Perseid Meteor Shower originate from the Comet
Swift-Tuttle, which has an orbital period of 133 years, leaving
behind a trail of dust and grit. Comet Swift-Tuttle was discovered in
1862 and returned for viewing in 1992.
Comet Swift-Tuttle measures about
16-miles across, much larger than the object that is thought to have
fallen to Earth which resulted in the extinction of the dinosaurs.
Comet Swift-Tuttle will make a very close approach to the Earth in
the year A.D. 4479. Scientists are now studying whether some day
Comet Swift-Tuttle could impact the Earth. Comet Swift–Tuttle has
been described as "the single most dangerous object known to
humanity."
It was 150
years ago that famous Italian astronomer Giovanni Schiaparelli
discovered that comets are the cause of Meteor Showers. Of course,
Schiaparelli is best known for observing, what he called, “canali,”
on the surface of Mars during the “Great Opposition” of Mars in
1877. In English, “canali” translates as channels. However, some
people, particularly American businessman and amateur astronomer
Percival Lowell, mistranslated the word to mean canals, giving the
impression that such infrastructure may have been constructed by
intelligent Martians.
In
1862, two American astronomers independently discovered (within three
days of each other), what was originally designated Comet 1862III.
Today, this rather famous comet is known by the name Swift-Tuttle, in
honor of these two astronomers: Lewis Swift, his first comet
discovery using a 4.5-inch refractor telescope, and Harvard College
Observatory Astronomer Horace P. Tuttle, using the Observatory's
15-inch refractor telescope.
It
was four years later, in 1866, when Schiaparelli matched the orbit of
Comet Swift-Tuttle and the orbit he had previously plotted for the
annual Perseid Meteor Shower. This was the first direct correlation
between comets and Meteor Showers. The same year, he calculated the
orbit of the Leonid Meteor Shower, and it was soon found that this
orbit coincided with the orbit of the newly-discovered, but small,
Comet Temple-Tuttle. From Schiaparelli's work, it was established
that Meteor Showers came from comets.
So, the time for viewing is right and
the lack of moon-light is great. And, of course, with the warm
weather most of us experience in the Northern Hemisphere, this time
of year, what could be better for viewing meteors?
Of course, Meteor Showers. like all
celestial observations, are weather-permitting. If the weather in
your area does not permit direct viewing outdoors of this Meteor
Shower, it can be viewed during special web-casts on the Internet.
A cautionary note for those who find it
necessary to watch the Perseid Meteor Shower on the Internet. The
video camera, used for each web-cast, can only aim at one part of the
sky at a time. Hence, do not expect to see as many meteors as you
might see with your own eyes outside. Outdoors, you can easily scan
the entire sky for meteors, while a camera aimed at one area of the
sky will only be able to see the meteors that enter that particular
part of the sky.
Internet Sites for Viewing Perseid Meteor Shower Near Peak ---
Bareket Observatory, Israel - Aug. 11, 3:00 to 8:00 p.m. EDT / Aug. 11, 19:00 UTC to Aug. 12 0:00 UTC (Using CCD camera, which automatically refreshes):
Link >>> http://www.bareket-astro.com/en/astronomical-webcasts/2016-s-perseids-meteor-live-webcast.html
Slooh Community Observatory - Aug. 11, 8:00 p.m. EDT / Aug. 12, 0:00 UTC:
Link >>> http://main.slooh.com/event/the-perseid-meteor-shower-2016/
NASA - BOTH on Aug. 11 and on Aug. 12 at 10:00 p.m. EDT / Aug. 12 and on Aug. 13 at 2:00 UTC: Link >>> http://www.ustream.tv/channel/nasa-msfc
Internet Links to Additional Information ---
History of the Perseid Meteor Shower:
Link >>> http://meteorshowersonline.com/perseids.html
Perseid Meteor Shower: Link >>> https://en.wikipedia.org/wiki/Perseids
Comet Swift-Tuttle: Link >>> https://en.wikipedia.org/wiki/Comet_Swift%E2%80%93Tuttle
Constellation Perseus: Link >>> https://en.wikipedia.org/wiki/Perseus_%28constellation%29
Meteor Shower: Link >>> https://en.wikipedia.org/wiki/Meteor_shower
Meteor: Link >>> https://en.wikipedia.org/wiki/Meteoroid#Meteor
Meteoroid: Link >>> https://en.wikipedia.org/wiki/Meteoroid
Meteorite: Link >>> https://en.wikipedia.org/wiki/Meteoroid#Meteorites
Fifth largest fragment of the meteorite which struck Barringer Meteor Crater near Winslow, Arizona, which was displayed at Pittsburgh's original Buhl Planetarium and Institute of Popular Science:
Link >>> http://buhlplanetarium2.tripod.com/Buhlexhibits.htm#meteorite
Related Blog Post ---
"NASA: Perseid Meteor Shower Has Most Fireballs." 2013 July 27.
Link >>> http://spacewatchtower.blogspot.com/2013/07/nasa-perseid-meteor-shower-has-most.html
Sources:
Glenn A. Walsh Reporting for SpaceWatchtower, a project of Friends of
the Zeiss; NASA.
2016 Aug. 11.
2016: 75th Year of Pittsburgh's Buhl Planetarium Observatory
Link >>> http://spacewatchtower.blogspot.com/2016/01/astronomical-calendar-2016-january.html
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gaw
Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://buhlplanetarium.tripod.com/fotz/ >
Electronic Mail - < gawalsh@planetarium.cc >
SpaceWatchtower Blog: < http://spacewatchtower.blogspot.com/ >
Also see: South Hills Backyard Astronomers Blog: < http://shbastronomers.blogspot.com/ >
Barnestormin: Writing, Essays, Pgh. News, & More: < http://www.barnestormin.blogspot.com/ >
About the SpaceWatchtower Editor / Author: < http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod. com/#news >
Twitter: < https://twitter.com/spacewatchtower >
Facebook: < http://www.facebook.com/pages/ SpaceWatchtower/ 238017839577841?sk=wall >
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
< http://www.planetarium. cc >
* Adler Planetarium, Chicago:
< http://adlerplanetarium. tripod.com >
* Astronomer, Educator, Optician John A. Brashear:
< http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
< http://www.andrewcarnegie. cc >
* Civil War Museum of Andrew Carnegie Free Library:
< http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
< http://inclinedplane.tripod. com >
* Public Transit:
< http://andrewcarnegie2.tripod. com/transit >
2016: 75th Year of Pittsburgh's Buhl Planetarium Observatory
Link >>> http://spacewatchtower.blogspot.com/2016/01/astronomical-calendar-2016-january.html
Like This Post? - Please Share!
Want to receive SpaceWatchtower blog posts in your inbox ?
Send request to < spacewatchtower@planetarium.cc >..
gaw
Glenn A. Walsh, Project Director,
Friends of the Zeiss < http://buhlplanetarium.tripod.com/fotz/ >
Electronic Mail - < gawalsh@planetarium.cc >
SpaceWatchtower Blog: < http://spacewatchtower.blogspot.com/ >
Also see: South Hills Backyard Astronomers Blog: < http://shbastronomers.blogspot.com/ >
Barnestormin: Writing, Essays, Pgh. News, & More: < http://www.barnestormin.blogspot.com/ >
About the SpaceWatchtower Editor / Author: < http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/ >
SPACE & SCIENCE NEWS, ASTRONOMICAL CALENDAR:
< http://buhlplanetarium.tripod.
Twitter: < https://twitter.com/spacewatchtower >
Facebook: < http://www.facebook.com/pages/
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
< http://www.planetarium.
* Adler Planetarium, Chicago:
< http://adlerplanetarium.
* Astronomer, Educator, Optician John A. Brashear:
< http://johnbrashear.tripod.com >
* Andrew Carnegie & Carnegie Libraries:
< http://www.andrewcarnegie.
* Civil War Museum of Andrew Carnegie Free Library:
< http://garespypost.tripod.com >
* Duquesne Incline cable-car railway, Pittsburgh:
< http://inclinedplane.tripod.
* Public Transit:
< http://andrewcarnegie2.tripod.
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