Travel journal

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Impact Alert on Jupiter

Something struck the largest planet in the solar system last week.

Impact flash on Jupiter. Credit: the Société Lorraine d’Astronomie (Screen Capture).

It’s always worth keeping an eye out for the unexpected, even during routine observations. Just such a surreptitious occurrence happened just last week, when observers from South America to Europe caught sight of a bright flash on Jupiter.

The Impact: The event occurred around 22:39:37 Universal Time (UT) 6:39:37 AM Eastern Daylight Saving time (EDT) on September 13th in the equatorial zone of Jupiter. The event also happened to transpire during an ongoing shadow transit of the innermost Galilean moon Io, while it was casting its shadow back on to the cloud tops of Jove. Most likely, the flash was due to a comet or asteroid a few hundreds of meters across, burning up in the atmosphere of Jupiter. No impact scar was noted on the evenings after the event. The discovery sent observers around the world scrambling to review video and photos taken around the same time, yielding multiple confirming views of the same impact flash. News of the impact made its way around the astronomical community via online message boards and social media, most notably Twitter, the first place we heard about the sighting.

This impact occurred at an ideal time, as Jupiter just passed opposition early last month. As the name implies, this is the point when Jupiter is ‘opposite’ to the Sun as seen from the Earth, rising in the east as the Sun sets in the west. Orbiting the Sun once every 11 years, Jupiter reaches opposition once roughly every 13 months, moving about one constellation eastward along the zodiac annually as it does so. Jupiter is also a fast rotator, spinning on its axis once every 10 hours. This also means that you can see the entirety of the planet around opposition, in one night.

History of impacts: Of course, the memory of that most famous of all planetary impacts is still a fresh–that of Comet Shoemaker-Levy 9 hitting Jupiter back in 1994. At the time, it was thought that such impacts were relatively rare.. but no less than seven impacts have been witnessed on Jupiter in the quarter century since Comet Shoemaker-Levy 9 made its cosmic crash into Jove. This is a testament to the rise of modern planetary imaging and video technology, allowing for nearly constant coverage of the planet worldwide… how many impacts managed to sneak by the eyes of observers before the 21st century?

Current thinking among planetary astronomers is that Jupiter acts as a sort of goal tender for the inner solar system, deflecting and taking hits from many of the incoming intruders from the distant outer solar system. In fact, any incoming comet stands about a 40% chance of having its orbit altered by Jove during a perihelion passage… this famously happened to Comet Hale-Bopp in the late 1990s, which had its orbit shortened by several thousands of years.

Be sure to keep a sharp eye out, even during routine astronomical observations… you never know what might just turn up.

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Enter the Equinox: Top Astronomy Highlights for September 2021

September is equinox month. Nights are getting longer in the northern hemisphere, meaning more time under dark skies before the chill of northern hemisphere winter sets in.

The September Sky: The glories of the summer Milky Way still linger post dusk. Up north, the famous summer triangle asterism rides high, with the stars Deneb, Altair, and Vega at its three corners.

The biannual equinox is short for ‘equal nights,’ a moment twice a year (once in March and again in September) when the rotational pole of the Earth is at a 90 degree perpendicular angle to the Sun, and day and night are equal worldwide. The equinox season is also special for a few other reasons: One is because it also marks GEOSat eclipse season. This is the period of a few weeks on either side of the equinox where distant satellites in geostationary/geosynchronous orbit seem to flare briefly into visibility, before vanishing into Earth’s shadow. Another phenomenon to watch for near the equinox is a peak in aurora activity. This biannual surge used to be a complete mystery until it was explained by what’s known as the Russell-McPherron Effect, which posits that solar wind streams through fissures opened in the Earth’s magnetic field. This occurs because the opposing magnetic field of the Earth is at its weakest angle right around the equinox. In 2021, we’re just now coming off a profound solar minimum, as Solar Cycle #25 gets underway in earnest. The jury is still out on whether or not the next solar cycle will ‘dazzle’ or ‘fizzle,’ though we’ve already seen some heightened solar activity worldwide in late August.

The Moon in September 2021: First Quarter Moon occurs on September 13th, and Last Quarter Moon occurs on September 28th, meaning the dark of the Moon (the best times for deep sky observations in the evening) runs from the 1st to the 13th centered on New Moon around September 7th, and resumes at the end of the month on September 29th and 30th. Of course, the Moon is a fascinating object to study in its own right, especially near Quarter phase when mountains and craters stand out in sharp contrast along the daylight/terminator.

The Planetary Rundown for September 2021: This month offers a true treat for evening skywatchers, as every naked eye planet is visible immediately after sunset. Mars is toughest, at just 12 degrees from the Sun at the start of the month, well below Mercury and Venus to the west. The gas giant planets Jupiter and Saturn rule the night rising in the east, fresh off of opposition last month. As an extra challenge, try spotting +8th magnitude Neptune with binoculars or a telescope in Aquarius this month. Fun fact: Neptune was discovered in the same constellation in 1846 after predictions made by astronomer Urbain Le Verrier), and has only completed one orbit in the last decade since discovery.

Highlighted object (northern hemisphere) Messier 57 The Ring Nebula – it was one of the first deep sky objects I ever went after. Situated in the constellation of Lyra the Lyre, M57 is a fine planetary nebula located about midway between the bright stars Beta and Gamma Lyrae, making it an easy find. I can just spy the ‘ghostly doughnut’ of M57 with binoculars from a dark sky site, and it really jumps out in a telescopic view. M57 is located approximately 2,300 light-years distant.

What you’re seeing is a star at the end of it’s life, ejecting gas and dust in its final death throes back into space. A challenging +15th magnitude white dwarf sits in the center of M57. Our Sun may do the same about 5 billion years from now, though a 2013 study cast doubt on whether we will also one day host a planetary nebula for future denizens of the Milky Way to enjoy at star parties. Fun fact: the term ‘planetary nebula’ actually has very little to do with planets: rather, early astronomers such as Charles Messier thought they appeared ‘planetary-looking’ while he was compiling his famous deep-sky catalog… and the name stuck.

Highlighted object (southern hemisphere): The Wild Duck Cluster Messier 11 – Many observers tend to overlook open clusters, which is a shame. Often, these loose stellar groupings still have enough ‘punch’ to go after, even from light-polluted urban sites. One of my favorites is M11. I often think of it as in the constellation of Aquila as it lies just off of the Eagle’s tail, but it’s actually just across the border in the tiny constellation of Scutum the Shield.

M11 is at southern declination of just over -6 degrees, making it a fine object for either hemisphere. At 6,200 light-years distant, M11 lies in the Sagittarius Arm of the Milky Way, towards the galactic center. At the eyepiece, M11 has a ‘powdered sugar’ look.

Challenge object (Northern Hemisphere): While you’re in the constellation Lyra checking out M57, try and see if you can resolve the famous ‘Double-Double’ star Epsilon Lyrae. The quadruple system is about 1.5 degrees from the brilliant Vega. Splitting the 210” pair is easy, even in binoculars; the challenge is to split the ‘pair into pair(s),’ both of which are only about 2.5” apart. This amazing system lies 162 light-years distant.

Challenge object (Southern Hemisphere): It’s a true irony of the night sky. Red dwarf stars, the most common type of stars in the universe are too faint to see with the naked eye. One of the brightest is the +6.6 magnitude star AX Microscopium in the obscure constellation of the Microscope. This star is 12.9 light-years distant, and offers a fine example of a nearby solitary red dwarf to check off of your life observing list. The coordinates for AX Microscopium are: RA: 21 Hours 18’ 35”, Declination -38 Degrees 46’ 49”.

Top Astronomy Events for September 2021

7th-New Moon

14th-Mercury greatest elongation (27 degrees east of the Sun at dusk)

14th-Neptune at opposition

15th-GEOSat eclipse season

17th-Comet 6P/d’Arrest at perihelion (+9th magnitude, 93 degrees east of the Sun in Sagittarius at dusk)

20th-Full Harvest Moon

20th-762 Pulcova occults +7 magnitude star for Mexico and US, in the brightest asteroid stellar occultation for 2021.

22nd-Southward Equinox

23rd-Aurora season


Nébuleuse de la méduse
Travel journal

Monday, February 8

1h12 AM

Today we embarked on a journey twenty thousand leagues under the sea aboard the Stellina station. We never imagined meeting a huge celestial jellyfish on our way. Bewitched by the movements of her radiant and transparent body, we spent 5 hours watching her swimming majestically in this sea of ??stars called Gemini. What marine animal are we going to meet again?

Nébuleuse de la méduse Object: IC 443 Jellyfish Nebula
Date: 08/02/2021
Total exposure time: 5 hours
Location: United-States
Auhor: Brian P.

m8 process
Travel journal

Friday, July 31

12:56 AM

This month, we’re heading to the constellation of Sagittarius from our base in Namibia. Fleeing the overwhelming heat of the world’s oldest desert, the Namib, we’re diving into the heart of the pink Lagoon. The nebula stretches deep over 100 light years. On our way, we cross star reefs and Bok globules. We narrowly avoid being engulfed by a tornado caused by the emission of ultraviolet rays from a massive star, tunneling into an even darker region. Halfway in, we find ourselves in the area called the Hourglass Zone and witness, with awe, the birth of young stars that will in turn illuminate this immense expanse of cosmic gas..

m8 process

Object: M8 Lagoon Nebula
Date: 01/07/2020
Stacked images: 360x10s
Total exposure time: 1 hour
Location: Namibia
Author: Sebastien A.

NGC5128 (233 exp)
Travel journal

Monday, June 1

02:12 AM
Fifth-brightest galaxy in the sky, Centaurus A mesmerized us all.

Glaciers melting in the dead of night.
And the superstars sucked into the supermassive blackhole*
You set our Stellina alight.

NGC5128 (233 exp)

Object: Centaurus A Galaxy
Date: 01/06/2020
Stacked images: 174x10s
Total exposure time: 30 minutes
Location: Namibia
Author: Sebastien Aubry

*Extract from Supermassive Black Hole (Muse)


Travel journal

Tuesday, May 5

01:34 AM
Off we go, on the wings of adventure, riding the Atlas comet through outer space. Into the roaring unknown, we’re uncovering space’s mysteries, remembrance of things past. As we retreat, temperatures warm and our comet is fading away. Farewell Atlas!
Let take the Swan’s way.


Object: Comet SWAN C/2020 F8
Date: 05/05/2020
Stacked images: 103x10s
Total exposure time: 1 hour and 46 minutes
Location: Keetmanshoop, Namibie
Author: Sebastien Aubry and Pierik Falco


Object: Comet ATLAS
Date: 23/04/2020
Stacked images: 535x10s
Total exposure time: 1 hour and 37 minutes
Location: Switzerland
Author: Pierik Falco

Travel journal

Friday, April 3

At first, we thought that someone had thrown a snowball on our lens. But is was not melting. The smear became crispier, ready to bang in the universe.

Object: NGC 5139 Omega Centauri
Date: 03/04/20
Stacked images: 147x10s
Total exposure time: 24min
Location: Namibia
Author: The Adventurer of the Third Planet for Vaonis

Travel journal

Thursday, March 19

We were cruising through the Carina, heading to HD95358 star’s station for a research project, when we got lost on our way, deviated by unexpected interstellar winds. It was darkness into darkness, a space where time seemed like it has never begun. We managed to find our way back, annoting our discovery in our journal, determined to unveil the secrets of this dark nebula some day.

Object: Dark nebula near HD95358
Stacked images:
Total exposure time:
2 hours and 7 minutes

Travel journal

Wednesday, February 26

We thought we had discovered two dusty seashells in the midst of the sky. Around them, tiny lights sparkling like cristals in the sand. Estimating their distance to be 12 million light-years away, we prepared our engine for a long road at the speed of light.
Half-way, we spot a bizarre object: an intriguing cone. A Brownish red, as though wrapped in crispy dried leaves. It seems to be burning from one end. It was not a seashell after all… We could smell its warm flavors.

Object: M81 Bode’s Galaxy (left) M82 Cigar Galaxy (right)
Stacked images:
Total exposure time:
38 minutes
Montpellier, France