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Cosmic Rebels & Celestial Farewells · Star Trails: From Backyard Astronomy to Cosmic Wonder

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  Howdy Star Gazers and welcome to this episode
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  of Star Trails. I'm Drew and I'll be your guide
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  to the night sky for the week starting April
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  27th through May 3rd. This week a new moon promises
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  darker skies, the summer triangle points the
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  way to warmer days, and did you know stars sometimes
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  run away from home? More on that weird phenomenon
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  later. So grab a comfortable spot under the night
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  sky and let's get started. Before we dive into
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  this week's highlights, a quick update about
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  Comet C2025F2, also known as Comet Swan. Last
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  week we talked about this comet potentially putting
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  on a good show. Unfortunately, after the episode
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  aired, astronomers reported that Comet Swann
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  began to disintegrate as it approached the Sun.
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  This was likely due to the comet's first venture
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  into the inner solar system, where intense heat
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  and gravitational forces broke its nucleus apart.
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  Interestingly, a cloud of debris remained visible
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  shortly after the breakup, but of course that's
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  fading fast. With that, we say goodbye to Comet
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  Swan. As of now, I don't know of any other comets
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  expected to make a splash this year, but you
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  never know what might turn up. Keep in mind,
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  we didn't know Swan was out there until about
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  a month ago. Closer to home, tonight marks the
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  new moon, meaning our skies will be beautifully
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  dark and ideal for observing those fainter celestial
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  objects, such as galaxies and nebula. As the
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  week moves on, the moon will gradually brighten
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  into a delicate waxing crescent, reaching about
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  40 % illumination by the week's end. This crescent
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  will be visible shortly after sunset. Speaking
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  of bright sights, Venus reaches its greatest
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  illuminated extent this week, blazing in the
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  pre -dawn eastern sky. Venus will be exceptionally
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  bright, making it hard to miss if you're an early
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  riser. On the very next morning, April 28th,
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  Saturn joins Venus, creating a lovely close pairing
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  just under 4 degrees apart. Mars continues its
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  journey across the sky, now moving closer to
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  the famous Beehive Cluster, or M44. Binoculars
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  will show you Mars as it passes near this sparkling
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  open star cluster in the constellation Cancer.
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  Jupiter remains a prominent evening planet easy
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  to spot after sunset toward the western sky.
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  With a telescope, you'll easily spot its Galilean
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  moons dancing around it. For an added challenge,
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  look for a transit of one of the moons and see
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  if you can spot its shadow moving across Jupiter.
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  You can use an online tool such as Sky & Telescope's
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  Jupiter's Moons Calculator to determine when
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  events like this happen. I'll include a link
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  in the show notes. While the Lyrid meteor shower
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  peaked last week, keep an eye out, you might
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  still catch some lingering meteors streaking
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  across the sky, especially in the early part
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  of the week. Additionally, the Eta Aquarid meteor
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  shower is starting to ramp up, and although it
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  peaks next week, you might still see a few early
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  meteors during the pre -dawn hours, particularly
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  from darker locations. Now, shifting our gaze
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  to constellations, let's explore the emerging
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  summer triangle. This well -known trio of bright
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  stars, Vega, Deneb, and Altair, begins to rise
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  in the east around 10 pm, signaling the approach
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  of warmer months. Vega, in the small yet vibrant
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  constellation Lyra, is the brightest of the three,
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  and has been central to myths connected to music
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  and poetry. Lyra is home to the Ring Nebula.
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  M57, a beautiful planetary nebula visible as
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  a tiny smoke ring in small telescopes. Also noteworthy
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  is Epsilon Leary, famously known as the Double
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  Double, where careful observation reveals not
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  just one, but two pairs of stars orbiting closely
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  together. The constellation Cygnus the Swan is
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  marked by Deneb, one of the farthest bright stars
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  visible without optical aid. Within Cygnus, you'll
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  find the impressive North America Nebula, NGC
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  7000, named for its striking resemblance to our
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  continent, and the elegant Veil Nebula, the ghostly
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  remnants of a supernova explosion. Don't miss
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  Alberio at the Swan's Head, a double star pairing
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  with golden and blue hues. Have you ever heard
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  of a runaway star? These cosmic rebels have broken
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  free from their stellar neighborhoods and are
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  now barreling through the galaxy at astonishing
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  speeds. sometimes fast enough to escape the Milky
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  Way altogether. In simple terms, a runaway star
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  is a star moving significantly faster than the
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  stars around it, often hundreds of kilometers
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  per second. These stars don't just meander along
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  with the gentle galactic rotation like most of
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  their neighbors. They're hurtling through space
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  like they've got somewhere to be. Many are on
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  paths that suggest they've been violently ejected
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  from their original homes, flung out into the
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  galaxy by powerful forces. There are two main
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  mechanisms thought to be responsible for this
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  high -velocity behavior. One theory involves
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  supernova explosions in binary systems. In this
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  scenario two stars orbit one another in a binary
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  system. When the more massive star reaches the
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  end of its life and explodes in a supernova,
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  the sudden release of mass can destabilize the
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  system. The surviving star might be sent flying
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  off into space at tremendous speeds. The violence
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  of a supernova is enough to break the gravitational
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  bond and the energy imparted can slingshot the
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  remaining star into a lonely galactic journey.
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  Another theory points to gravitational interactions
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  in star clusters. In dense star clusters, particularly
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  those near the galactic center or in globular
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  clusters, three - or four -body interactions
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  can fling a star out at high velocity. This is
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  a bit like a cosmic game of pool. One star gets
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  knocked out of the cluster owing to complex gravitational
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  interactions with multiple other stars or a massive
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  black hole. One of the most exciting subsets
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  of runaway stars are hypervelocity stars. These
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  are moving so fast they're on escape trajectories
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  out of the galaxy entirely. These were first
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  predicted theoretically in the 1980s and confirmed
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  observationally in the 2000s. They often originate
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  from interactions with the supermassive black
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  hole at the center of the Milky Way. In a tight
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  dance between stars and the black hole's immense
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  gravity, one member of a binary pair can be captured
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  while the other is flung away at speeds exceeding
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  a million miles per hour. Among these standout
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  objects is HV2112, and I don't know if that's
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  a rush reference, but it would be appropriate.
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  2112 is a curious and controversial star located
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  in the small Magellanic cloud. While not technically
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  a hypervelocity star, it's earned attention for
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  its bizarre chemical makeup and potential status
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  as a thorn -zeitkau object, a theoretical hybrid
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  of a red supergiant and a neutron star. In terms
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  of observational characteristics, runaway stars
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  don't look all that different from other stars,
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  at least not through traditional telescopes.
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  They may appear as hot blue O or B -type stars,
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  large, young, and luminous. In other cases, they
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  might be older or redder stars. The key difference
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  is not what they look like, but how they move.
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  Their proper motion, that's their movement across
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  the sky relative to more distant stars, can be
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  measured over time with the help of space telescopes
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  and long -term sky surveys. Modern surveys like
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  Gaia have been instrumental in identifying runaway
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  stars. Gaia precisely measures the positions,
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  motions, and distances of more than a billion
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  stars in the Milky Way. By plotting the motion
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  vectors of these stars, astronomers can spot
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  the few that are zooming through the galaxy in
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  ways that don't conform to the general structure
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  and rotation of the Milky Way. As for backyard
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  astronomy, runaway stars aren't something we
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  normally seek out. They don't emit unique light
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  or have any distinguishing visual characteristics.
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  But some of the most famous runaway stars, like
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  Zeta Ophiuchae, are visible with amateur telescopes
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  or even binoculars. Zeta Ophiuchae is a massive
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  hot blue star that's plowing through space and
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  creating a visible bow shock. That's an arc -shaped
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  wave in the interstellar medium, much like a
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  boat cutting through water. Infrared images reveal
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  this shock wave in beautiful detail. So next
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  time you're under a clear sky, remember, somewhere
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  out there, maybe even above your head, a star
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  is fleeing a supernova. escaping a black hole,
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  or wandering alone from a starry birthplace it
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  no longer calls home. If you found this episode
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  helpful let me know and feel free to send in
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  your questions and observations. The easiest
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  way to do that is by visiting our website StarTrails
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  .Show. This is also a great way to share the
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  show with friends. Until next time, keep looking
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  up and exploring the night sky. Clear skies everyone!