Latest / Star Trails: From Backyard Astronomy to Cosmic Wonder / Dark Skies, Elusive Light, and Pluto’s Legacy

Transcript

Dark Skies, Elusive Light, and Pluto’s Legacy · Star Trails: From Backyard Astronomy to Cosmic Wonder

• 0:00
  Howdy Stargazers and welcome to this episode of Star Trails.
• 0:11
  I'm Drew and I'll be your guide to the night sky for the week starting February 23rd through
• 0:16
  March 1st.
• 0:19
  This week we welcome darker skies thanks to an upcoming new moon.
• 0:23
  Mercury returns to the dusk sky and right now is a great time to hunt for the elusive
• 0:29
  zodiacal light.
• 0:31
  Later in the show we'll cover some low-key deep sky objects that are worth tracking down
• 0:36
  in binoculars and small telescopes and we'll journey way out to the edge of the solar system
• 0:42
  and celebrate the anniversary of Pluto's discovery.
• 0:47
  But first let's take a look at what you can see from your backyard.
• 0:53
  This week the moon will be a thin waning crescent rising just before dawn.
• 0:59
  The new moon occurs on the evening of February 27th.
• 1:03
  Nights around the new moon are perfect for stargazing and astrophotography due to the
• 1:08
  absence of moonlight.
• 1:12
  Mercury returns to our night skies this week completing the parade of visible planets.
• 1:18
  Look for a close encounter between Mercury and Saturn very low on the western horizon
• 1:23
  just after sunset on the 25th.
• 1:26
  The other planets are strewn out along the ecliptic plain.
• 1:31
  Venus remains in the west and extremely bright.
• 1:34
  Jupiter is still nearly directly overhead after sunset and Mars is toward the east in
• 1:40
  Gemini.
• 1:42
  On the evening of February 28th immediately after sunset look towards the west to spot
• 1:48
  a wisp of a crescent moon just above the horizon.
• 1:52
  You'll find Mercury less than 5 degrees above the moon.
• 1:57
  For a rough estimate hold your fist out at arm's length.
• 2:01
  That spans roughly 10 degrees.
• 2:04
  The brilliant Venus will be easily visible above the moon and Mercury.
• 2:09
  Plan to start your observations shortly after sunset to catch the planetary alignments.
• 2:15
  As the night progresses and the sky darkens further shift your focus to constellations
• 2:20
  and deep sky objects.
• 2:28
  This is one of the best times of the year to catch the subtle but fascinating phenomenon
• 2:33
  known as the zodiacal light.
• 2:36
  A soft ethereal glow that appears in the sky just after sunset or before sunrise.
• 2:42
  It's often mistaken for lingering twilight but it's actually something much more cosmic.
• 2:49
  The zodiacal light is a faint triangular glow that extends from the horizon tapering upward
• 2:55
  along the path of the ecliptic.
• 2:58
  The same celestial highway where the sun and planets travel.
• 3:03
  Unlike city light pollution this glow isn't artificial.
• 3:08
  It's sunlight scattering off a vast cloud of interplanetary dust.
• 3:13
  Many particles left behind by comets and asteroid collisions over billions of years.
• 3:20
  In the northern hemisphere late winter and early spring are the best times to catch the
• 3:25
  zodiacal light in the evening.
• 3:28
  Look to the western horizon about 90 minutes after sunset in a dark sky away from city
• 3:34
  lights.
• 3:35
  It appears as a soft milky glow stretching upward from the horizon.
• 3:40
  If you're an early riser you can spot it before dawn in the opposite season.
• 3:45
  So for the northern hemisphere that means late summer and early autumn in the east before
• 3:50
  sunrise.
• 3:52
  The dust creating this glow isn't just floating aimlessly.
• 3:56
  It's caught in the gravitational grip of the sun forming a disk shaped cloud along the
• 4:01
  plane of our solar system.
• 4:04
  NASA's Juno spacecraft even detected signs that some of this dust originated from Mars.
• 4:10
  Meaning our cosmic neighborhood is constantly exchanging material.
• 4:16
  This same dust also plays a role in meteor showers when Earth plows through denser regions
• 4:22
  of it.
• 4:24
  Ancient sky watchers noticed the zodiacal light long before we understood its origin.
• 4:30
  Some early astronomers thought it was part of the milky way while in the middle ages
• 4:35
  it was sometimes linked to supernatural omens.
• 4:39
  The name zodiacal comes from the fact that the light follows the zodiac constellations,
• 4:45
  the backdrop for the sun's annual journey across the sky.
• 4:49
  Remember you'll need very dark, clear skies to catch it so make sure you let your eyes
• 4:55
  adjust the darkness when you go out to try and observe it.
• 5:06
  This week's new moon brings some of the darkest skies of the month so what better time to
• 5:11
  chase down some deep sky objects?
• 5:15
  While the Orion Nebula or the Andromeda Galaxy are always standouts, I want to highlight some
• 5:21
  hidden gems that are often overlooked.
• 5:24
  The best part is that you don't need a giant telescope to see them, just grab your binoculars
• 5:29
  or a small scope.
• 5:31
  For best results use 10x50 or larger binoculars.
• 5:36
  The Fainter targets will require a 4-6 inch telescope.
• 5:40
  A quick side note, many of these objects are from the New General Catalog of Nebula and
• 5:47
  Clusters of Stars, which contains some 7,840 objects.
• 5:54
  So when we refer to items as NGC, followed by a number, know that it's from the New
• 5:59
  General Catalog.
• 6:02
  Many of you are probably familiar with the Messier Catalog and those objects simply start
• 6:07
  with an M.
• 6:09
  The first target on our list is NGC 2362, also known as the Tau Canis Majoris Cluster.
• 6:19
  This bright open cluster sits in the constellation Canis Major, not far from the brilliant star
• 6:25
  Sirius.
• 6:27
  What makes it special is that a single intensely bright blue star, Tau Canis Majoris, sits
• 6:34
  at its center, outshining the surrounding stars.
• 6:38
  This cluster almost looks three-dimensional as if the stars are floating at different
• 6:43
  depths in space.
• 6:46
  It's sometimes called the Mexican Jumping Star because the central star appears to hover
• 6:51
  or jump out of the neighboring stars.
• 6:55
  To find it, look just south of Sirius and a pair of binoculars will reveal a tight glowing
• 7:00
  cluster of stars.
• 7:03
  In a small telescope, the surrounding stars become sharper, giving the cluster a jewel-like
• 7:08
  appearance.
• 7:10
  If you're a Star Trek fan, you'll love this next object, NGC 1662, also known as the Klingon
• 7:19
  Bird of Prey Cluster.
• 7:22
  This small open cluster is located in Orion, near the bright star Bellatrix, which marks
• 7:28
  Orion's left shoulder.
• 7:31
  What makes it unique is its distinctive V-shape, which strongly resembles a Klingon Bird of
• 7:37
  Prey from the Star Trek universe.
• 7:40
  With binoculars, you'll notice a scattered V-shaped group of stars, but in a small telescope,
• 7:47
  the pattern stands out even more clearly.
• 7:50
  It's a fun target and an easy one to find.
• 7:53
  Now, let's take a look at NGC 2232, a fantastic open cluster that often gets overlooked because
• 8:02
  it sits in the faint constellation Monoceros, the unicorn.
• 8:07
  It lies roughly between Betelgeuse in Orion and Procyon in Canis Minor.
• 8:14
  Through binoculars, you'll see a beautiful, loose scattering of stars with one noticeably
• 8:19
  bright central star.
• 8:21
  A small telescope will enhance the fainter members of the cluster, but it's truly a binocular
• 8:26
  friendly target that's easy to spot even in suburban skies.
• 8:31
  If you're looking for an open cluster that's simple but rewarding, this is a great choice.
• 8:37
  Now, if you're looking for a challenge, try tracking down NGC 247, also known as the
• 8:45
  Needle's Eye Galaxy.
• 8:48
  This elongated spiral galaxy is located in Cetus, south of Pisces.
• 8:54
  What makes it interesting is that it appears lopsided with a dark void on one side.
• 9:01
  Under dark skies, a small telescope will show an oval-shaped patch of light, though binoculars
• 9:07
  may only reveal a faint smudge.
• 9:11
  This galaxy is part of the Sculptor Group, a collection of galaxies that includes the
• 9:16
  brighter Sculptor Galaxy NGC 253.
• 9:21
  So if you're in a truly dark location, it's worth scanning the area for more galaxies.
• 9:27
  Up next, we have a two-for-one special, M46 and M47, a stunning pair of open clusters
• 9:36
  in Pupus.
• 9:38
  These two clusters are located close together and look fantastic in binoculars.
• 9:43
  M47 is bright and sparse, while M46 is fainter but more densely packed with stars.
• 9:52
  Inside M46, a small telescope reveals a faint planetary nebula, NGC 2438.
• 10:01
  It appears as a tiny glowing disk, almost like a ghostly bubble floating among the stars.
• 10:08
  This is a fun target to observe because it lets you see both a young star cluster and
• 10:13
  the remnants of a dying star in the same view.
• 10:18
  For something unique, check out NGC 2683, often called the UFO Galaxy.
• 10:26
  This spiral galaxy is located in the constellation Lynx, which sits between Gemini and the Big
• 10:32
  Dipper.
• 10:33
  NGC 2683 is seen edge-on, meaning it looks like a classic saucer-shaped UFO.
• 10:42
  On a small telescope, you'll see a thin elongated glow with a slightly brighter center.
• 10:48
  It's a great alternative to the Andromeda Galaxy, especially if you're looking for a
• 10:52
  new galaxy to track down.
• 10:55
  The final target on our list is NGC 281, also known as the Pac-Man Nebula.
• 11:03
  This faint emission nebula is located near Shadar, the brightest star in Cassiopeia.
• 11:10
  It gets its nickname because a dark notch in the nebula gives it the shape of Pac-Man
• 11:15
  from the classic arcade game.
• 11:18
  While binoculars won't reveal much, a small telescope equipped with a nebula filter, like
• 11:24
  an O3 or UHC filter, will bring out its faint glow.
• 11:30
  If you've already observed the Orion Nebula and want to try something more subtle, the
• 11:35
  Pac-Man Nebula is a fun challenge.
• 11:38
  As always, to get the best views, find the darkest sky possible.
• 11:43
  Use low magnification for clusters.
• 11:46
  And if you're looking at nebula, a filter will improve contrast.
• 11:51
  Remember to consult with a night sky app like Sky Safari or Stellarium if you're having
• 11:56
  trouble locating your target.
• 11:59
  That wraps up this week's hidden deep sky gyms.
• 12:02
  If you happen to catch any of these objects, let me know what you saw.
• 12:14
  In case you missed it, February 18 was Pluto Day.
• 12:19
  On that day in 1930, astronomer Clyde Tombaugh made history when he discovered Pluto at the
• 12:25
  Lowell Observatory in Flagstaff, Arizona.
• 12:29
  At just 24 years old, Tombaugh had been systematically searching for a ninth planet, known then as
• 12:36
  Planet X, which had been predicted by Percival Lowell in the early 1900s.
• 12:42
  Tombaugh used a device called a blink comparator, which allowed him to compare photographic
• 12:48
  plates taken on different nights to spot moving objects against the background of fixed stars.
• 12:55
  After months of painstaking work, he noticed a tiny dot shifting across the plates.
• 13:01
  That was Pluto.
• 13:02
  The discovery was formally announced on March 13, 1930, which happened to be both Percival
• 13:09
  Lowell's birthday and the anniversary of William Herschel's discovery of Uranus in
• 13:14
  1781.
• 13:16
  The name Pluto was suggested by an 11-year-old girl from England, Venetia Bernie, who was
• 13:23
  fascinated by mythology.
• 13:25
  The name was fitting as Pluto, the Roman god of the underworld, matched the distant and
• 13:31
  mysterious nature of the new planet, plus its first two letters, P.L., honored Percival
• 13:37
  Lowell.
• 13:39
  For 76 years, Pluto remained the ninth planet in our solar system, but as astronomers discovered
• 13:46
  more Pluto-like objects in the Kuiper Belt, like Eris, discovered in 2005, it became clear
• 13:53
  that our definition of a planet needed refining.
• 13:57
  On October 24, 2006, the International Astronomical Union redefined what it means to be a planet.
• 14:06
  Under the new criteria, a planet must, one, orbit the sun, two, be massive enough to be
• 14:13
  rounded by its own gravity, and three, have cleared its orbit of other debris.
• 14:20
  Pluto failed the third criterion as it shares its orbit with other Kuiper Belt objects.
• 14:26
  It was reclassified as a dwarf planet, sparking widespread controversy.
• 14:32
  The debate continues to this day, with some scientists arguing that Pluto should still
• 14:36
  be a planet due to its complex geology, atmosphere, and possible subsurface ocean.
• 14:43
  Interestingly, Pluto never completed a single orbit around the sun in the 76 years it was
• 14:49
  considered a planet.
• 14:52
  While Pluto may have been demoted, the New Horizons spacecraft, which flew past Pluto
• 14:57
  in July 2015, revealed it to be one of the most fascinating objects in the solar system.
• 15:04
  We now know Pluto has towering mountains made of water ice, nitrogen glaciers that flow
• 15:10
  like rivers, and a thin atmosphere that changes over time.
• 15:15
  Pluto's surface even features a giant heart-shaped plane called the Tombow Regio, in honor of
• 15:22
  its discoverer.
• 15:24
  So while Pluto's classification may have changed, its status as one of the most interesting
• 15:29
  worlds in our solar system remains unchallenged.
• 15:34
  And every February, we can celebrate the discovery that forever changed our understanding of the
• 15:39
  outer solar system.
• 15:44
  If you enjoyed this episode, let me know.
• 15:47
  The easiest way to do that is by visiting our website StarTrails.Show.
• 15:52
  This is also a great way to share the show with friends, and you can find transcripts
• 15:57
  of every episode.
• 15:59
  You can also find us on Blue Sky and Mastodon, and if you'd like to support the show by
• 16:05
  buying me a cup of coffee, be sure to visit the links in the show notes and on the website.
• 16:11
  Until next time, keep looking up and exploring the night sky.
• 16:15
  28 5 KAZA
• 16:18
  Another top watching episode is coming up soon.
• 16:29
  0 TAUN