Space and astronomy news
A relatively obscure meteor shower may put on a surprise performance in early December 2018. Chances are, you’ve never heard of the Andromedids, though it’s worth keeping an eye out for these swift-moving meteors over the next week. Continue reading “A 2018 Outburst From the December Andromedids?”
UPDATE – SpaceX has now set a firm date and time for the Spaceflight SSO-A launch from Vandenberg Air Force Base for Monday, December 3nd at 18:31 Universal Time (UT).
A unique smallsat mission promises to be the latest satellite “brighter than a Full Moon!” in the night sky… or not.
The Mission: We’re talking about Orbital Reflector, conceived by Trevor Paglen and fielded by the Nevada Museum of Arts. Dubbed as the “first art exhibit in space,” the $1.3 million dollar project seeks to put a smallsat payload with a deployable reflector in low Earth orbit. Continue reading “SpaceX to Launch 64 Satellites, Including Orbital Reflector”
You just never know when it comes to comets. Here it is mid-November, and we’d thought we had finished up writing about bright comets for 2018. That was until this past weekend, when a flurry of messages flashed across the Yahoo! Comets mailing list hinting that a new, possibly bright comet had been discovered. Come Monday morning November 12th, long period Comet C/2018 V1 Machholz-Fujikawa-Iwamoto was formally added to the International Astronomical Union’s Minor Planet list.
Continue reading “New Comet V1 Machholz-Fujikawa-Iwamoto Takes Observers by Surprise”
Not all oppositions are created equal. This week’s sky target offers a good case in point, as asteroid 3 Juno reaches its most favorable viewing position for the decade. Continue reading “Catching Asteroid 3 Juno at Its Best”
One. More. Comet. Though the next great ‘Comet of the Century’ has yet to make its appearance in 2018, we’ve had a steady stream of binocular comets this year, including Comets C/2017 S3 PanSTARRS, 38P Stephan-Oterma, and 21P Giacobini-Zinner.
Now, the calendar year may have saved the best for last, as periodic Comet 46P Wirtanen takes center stage. Continue reading “Comet 46P Wirtanen Rounds Out 2018”
Ready for one more? While all eyes are still following Comet 21/P Giacobini-Zinner as it glides through northern hemisphere skies, we’d like to turn your attention towards another icy interloper: periodic Comet 38P Stephan-Oterma. Continue reading “2018 Prospects for Obscure Comet 38P Stephan-Oterma”
Following the Moon lately? The up and coming Full Moon is the most famous of them all, as we approach the Harvest Moon for 2018. Continue reading “Heralding the 2018 Harvest Moon”
Watching the heavens on a nightly, or even casual basis? The web and modern technology has certainly altered the landscape of modern astronomy, (mostly) for the better. Once, we all huddled around cardboard planispheres, illuminated by red flashlights; now, it’s now a common sight to see illuminated smartphone apps accompanying telescopes at star parties, all waving skyward with virtual planetarium programs guiding users around the night sky.
Continue reading “Cosmic Watch Review: A Unique Perspective on the Night Sky”
A periodic comet may put on a fine show for northern hemisphere viewers over the next few months.
Comet 21/P Giacobini-Zinner is currently a fine binocular comet, shining at +8th magnitude as it cruises across the constellation Cassiopeia. This places it above the horizon for the entire night for observers north of the equator in August, transiting the local meridian at dawn. And unlike most comets that get lost in the Sun’s glare (like the current situation with C/2017 S3 PanSTARRS), we’ll be able to track Comet 21/P Giacobini-Zinner right through perihelion on September 10th.
This is because the comet is on a short period, 6.6 year orbit around the Sun that takes it from an aphelion of 6 Astronomical Units (AU) exterior to Jupiter’s orbit, to a perihelion of 1.038 AU, just 3.3 million miles (5.2 million kilometers) exterior to Earth’s orbit. The 2018 apparition sees the comet pass 0.392 AU (36.5 million miles/58.3 million kilometers) from the Earth on September 11th.
This is the closest passage of the comet near Earth since September 14th, 1946, and won’t be topped until the perihelion passage of September 18th, 2058. Its next cycle of passes to Earth closer than 0.1 AU aren’t until next century in the years 2119 and 2195, respectively.
Discovered by astronomer Michel Giacobini at the Côte d’Azur Observatory in Nice, France on the night of December 20th, 1900 as it was crossing the constellation Aquarius, the 21st periodic comet was recovered two orbits later by Ernest Zinner on October 23rd, 1913 as it passed a series of variable stars near Beta Scuti.
Though the comet generally tops out at +8th magnitude, it has been known to undergo periodic outbursts near perihelion, bringing it up about 3 magnitudes (about 16 times) in brightness. This occurred most notably in 1946.
Comet 21/P Giacobini-Zinner is also the source of the Draconid (sometimes referred to as the Giacobinid) meteors, radiating from the constellation Draco the Dragon on and around October 7th and 8th. Feeble on most years, this shower can produce surprises, such as occurred in 1998, 2005 and most recently in 2011, when a Draconid outburst topped a zenithal hourly rate of 400 meteors per hour, flirting with ‘meteor storm’ status. And while we’re not expecting a meteor storm to accompany the 2018 perihelion passage of Comet 21/P Giacobini-Zinner, you just never know… it’s always worth keeping an eye out on early October mornings for the “Tears of the Dragon,” just in case. Note that the Moon reaches New phase on October 9th, just a few days after the meteor shower’s expected annual peak, a fine time to watch for any unheralded Draconid outbursts.
Prospects for Comet 21P
The comet is visible from the northern hemisphere through the remainder of August and all through September as it glides across Auriga, Taurus and Gemini and visits several well known celestial sights. In fact, it actually transits in front of several deep sky objects, including Messier 37 (Sept 10th), and Messier 35 (Sept 15th).
The comet will be moving at about two degrees per day when it’s nearest to the Earth, on and around September 11th.
We begin to lose the comet, as it heads southward in late October. Still, the comet is over 50 degrees above the eastern horizon at dawn come October 1st as seen from latitude 30 degrees north, having maintained a similar elevation throughout most of September. Not bad at all.
Here are some upcoming dates with destiny for Comet 21/P Giacobini-Zinner:
August 19: Crosses into the constellation Camelopardalis.
August 29: Crosses into the constellation Perseus.
August 30th: Crosses into the constellation Auriga.
September 2: Passes one degree from the bright star Capella.
Sept 7-8: Grouped 2 degrees from the open clusters M36 and M38.
Sept 10: Photo-Op: Skirts very near the open cluster M37. Also reaches perihelion on this date, at magnitude +7.
Sept 11: Passes closest to the Earth, at 0.392 AU distant.
Sept 13: Nicks the corner of the constellation Taurus.
Sept 14th : Enters the constellation Gemini.
Sept 15th: Photo-Op: crosses in front of the open cluster M35.
Sept 16: Crosses the ecliptic southward and near the +3.3 magnitude star Propus (Eta Geminorum).
Sept 17: Crosses into Orion.
Sept 21: Crosses into Gemini.
Sept 23: Crosses into Monoceros.
Sept 24: Passes near the Christmas Tree Cluster, NGC 2264.
Oct 1: Crosses the galactic plane and the celestial equator southward.
Oct 7: Crosses in front of the open cluster M50.
Oct 10: Crosses into Canis Major.
Oct 31st: Passes near the bright star Aludra and may drop below +10th magnitude.
Binoculars are your best friend when you’re looking for comets brighter than +10th magnitude. With a generous field of view, binoculars allow you to sweep a suspect area until the faint fuzzball of a comet snaps into view. I like to ‘ambush’ a comet as it passes near a bright star, and a good time to spot comet 21/P Giacobini-Zinner is coming right up on September 2nd when it passes less than one degree from the bright +0.1 magnitude star Capella.
Don’t miss this year’s fine apparition of Comet 21/P Giacobini-Zinner, coming to a night sky near you.
How about that Total Lunar Eclipse this past July 13th? It has been a busy year for astronomy for sure, with two total lunar eclipses, a comet fading out from an unexpected burst of glory, and Saturn, Jupiter and Mars reaching opposition in quick succession.
Now, watch for a rare event this weekend, with the final eclipse for 2018 coming up on Saturday, August 11th, with a partial solar eclipse spanning northern Europe and the Arctic.
What’s so unique about this eclipse? Well, not only is it the last one for 2018, but it’s part of three eclipses in the second eclipse season of the year. Most seasons only feature two eclipses (one lunar and one solar) but every few years or so, it is possible to have a season with three: either lunar-solar-lunar (such as occurred in 2013) or solar-lunar-solar.
This is only possible when the middle eclipse occurs very near ascending or descending node along the ecliptic. The nodes are where the path of the Moon, inclined 5.1 degrees relative to the ecliptic plane intersect it—when these nodes are occupied by an alignment of the Earth, Sun and Moon (known as a syzygy, a fine word in Scrabble to land on a triple word score, though you’ll need a blank tile for the third ‘y’) a solar or lunar eclipse occurs. For an eclipse triple play, the middle eclipse needs to happen very near a node crossing, producing a fairly long eclipse. That’s exactly what happened on July 28th, when the Moon crossed through descending node just over an hour after crossing out of the Earth’s umbral shadow after the longest lunar eclipse for the 21st century.
This also leaves the Moon close enough to the opposite ascending node two weeks post and prior to July 28th on July 13th and August 11th to just nick the Sun for a partial solar eclipse, one over the Antarctic and one over the Arctic.
Eclipse Circumstances
Saturday’s partial eclipse touches down over the eastern coast of Canada at sunrise. From there, it sweeps eastward over Greenland, Iceland and the North Atlantic, with the Moon’s penumbra just grazing the northern United Kingdom before crossing over Scandinavia. Then, the shadow crosses over Asia, with a photogenic partial solar eclipse wrapping up at sunset over eastern China, the Koreas and the Russian far east.
Note that this eclipse is also a relative newcomer for its particular saros 155, as it is member 6 of a series of 71 eclipses. The saros just began less than a century ago on June 17th, 1928, and won’t produce its first total solar eclipse until September 12th, 2072 AD.
As of this writing, we’ve yet to see evidence of anyone carrying the eclipse live, though we’ll note it here if any webcast(s) surface.
When is the next one? Well, the next partial solar eclipse is on January 6th 2019, and the next total solar eclipse occurs on July 2nd, 2019.
Enter the Perseids
This weekend’s eclipse at New Moon also sets us up for a fine display of the Perseid meteors for 2018. This year, the Perseids are expected to peak on the morning of August 12th and August 13th. Watch for a zenithal hourly rate of 100 meteors per hour at the peak. A dependable annual favorite, the Perseids are debris remnants of period comet 109/P Swift-Tuttle.
Astronomer Gianluca Masi and the Virtual Telescope Project 2.0 will host a live webcast for the 2018 Perseids on August 12th starting at 20:30 UT.
Don’t miss the astronomical action worldwide this weekend, either live or online.
