Sanctuary among the stars

A quaint corner for avid sky watchers and space enthusiasts alike 🪐 All celestial observations and guides are made from a perspective of 4°N

[stellarluminosity]

The Star Compass

I have plunged deep into the rabbit hole of yet another fascinating art of ancient astronomy: Polynesian Wayfinding. I have been deeply intrigued the moment I learned that Scorpio is known as Manaiakalani, name of Maui's fishhook in Hawaiian mythology. So here's the main gist: Imagine travelling thousands of miles of nothing but the ocean in search of new islands. Compass? Sextant? Non-existent in that timeline. The only thing you can rely on? The sun, stars, current swells, winds, birds, clouds and any other signs of nature to anchor yourself as you look upon the endless horizon. For this post I will be focusing on navigation with the stars.

May I present the Star Compass! This is a modernized version of a star compass by Nainoa Thompson, the first native Hawaiian to practice ancient polynesian wayfinding techniques since the 14th century under the tutelage of the master navigator, Mau Piailug. For decades, it was only speculated that the pacific islanders 'stumbled upon' or discovered the islands by chance. To prove that they did not just drift passively with the currents and travel was intentional, the Polynesian Voyaging Society rebuilt a double-hulled voyaging canoe (waʻa kaulua). The canoe was named Hōkūleʻa, hawaiian name for Arcturus, brightest star of Bootes. (Funfact: Arcturus/Hōkūleʻa was chosen for the name as it is an important zenith star in Hawaii.). The voyage from Hawaii to Tahiti in 1976 using only traditional navigation techniques was a success. This has led to countless other successful voyages across Polynesia, Micronesia, Japan and US.

This star compass is more of a mental map, not an actual physical compass. The bird is where you are, on the canoe at the center. The compass is divided into 32 houses (11.25° each).

We have the cardinal points: Akau (N), Hema (S), Hikina (E), Komohana (W) Each quadrant represents the main winds: Ho'olua (NW), Ko'olau(NE), Kona (SW), Malanai (SE)

Then the 7 houses in each quadrant:

La: position of the sun, rising and setting

Aina: Land

Noio: A Hawaiian black noddy tern - also used in navigation since their flight paths indicate land.

Nalani: the Heavens

Naleo: Voices - the stars speak to the navigator

Haka: Empty - usually these spots are empty skies

Manu: Midway point of the cardinal directions

Each house acts as a bearing on the horizon. Master navigators memorized all key stars that can be used only when they are rising or setting. If a star has risen too high, they simply switched to another. For example, a star rising from Ko'alau La (NE) will set in Ho'olua La (NW). Every island also has a zenith star, the star declination matches the latitude of the location directly 90° overhead. For example seeing Hōkūleʻa (Arcturus) passing directly overhead indicates you are at Hawaii. The name also means "Star of Joy" or "Star of Gladness" because seeing it means they are "home". The zenith star for Tahiti is A'ā (Sirius) Remember, the star compass is not a static map. As you move further north or south, positions of the stars in the houses may change! Hōkūleʻa at the bottom of aina in Tahiti will be nearly touching Noio when near Maui. It requires dynamic calibration from the master navigators! This art was nearly lost had it not been revived by the efforts of the Polynesian Voyaging Society. May this knowledge be passed down for generations to come.

[stellarluminosity]

I got a cool book!!! I've always wanted a more in-depth guide as opposed to those that offer only bite size info.

As compared to other books I have, this one has info for each and every constellation, along with it's stars.

I have overspent yet again

[stellarluminosity]

BLOOD MOON TONIGHT!!

And this time it can be seen across Asia, western Australia, Africa, and some parts of Europe! I always remember saying "why every single eclipse or <insert any other cool celestial event> happens elsewhere?? NOT this time! This time about 70% of the world's population can witness it!

From 7 - 8th September

The Moon will be fully immersed in Earth’s darkest shadow. It will last around 82 minutes, making it one of the longest in recent years since 2022.

Prime Visibility Regions

Anyone in the dark pink region can see the eclipse in its entirety.

Best views and timings for key cities:

Mumbai (IST): ~11:00 PM on Sept 7 to 12:22 AM on Sept 8

Bangkok (ICT): ~12:30 AM – 1:52 AM (Sept 8)

Beijing (CST): ~1:30 AM – 2:52 AM (Sept 8)

London (BST): ~7:30 PM – 8:52 PM (Sept 7)

Istanbul / Cairo / Nairobi: ~8:30 PM – 9:52 PM (Sept 7) .

[stellarluminosity]

It's been a while since I saw such a glorious sunset as it has been nothing but rain the past few months. The colours just danced and swirl in such a magical way✨✨✨ Just right opposite this marvelous display, I am mesmerized by the stark contrast of the moon glowing brightly against the twilight sky.

[stellarluminosity]

When Horus Blinked: The Oldest Record of a Variable Star

The Cairo Calendar, also known as Papyrus Cairo 86637, dates back to around 1244 - 1163 BC. At a glance, it looks like a list of superstitions. Informing the reader which days were considered lucky or unlucky with each entry tied to mythological events involving Egyptian gods like Horus, Seth, and Ra.

A typical entry might read: “Day 12, Month III: Unlucky. On this day Seth fought with Horus. Do not begin a journey.” But behind the superstition lies the earliest record of a variable star, Algol, the "Winking Demon Star."

Algol is an eclipsing binary system, where one star periodically passes in front of the other. This causes the system’s brightness to dip, creating the illusion of a star that "blinks". Hence, in Greek mythology, Algol represents the Gorgon’s sinister winking eye. Today, we know Algol dims for about 10 hours, dropping to from mag 2.1 to 3.4, on a cycle of 2.867 days (2 days, 20 hours, 48 minutes).

In the records, Algol was likely represented as Horus with its periodic brightness influencing the calendar’s lucky days. Researchers from the University of Helsinki found that the calendar encoded two cycles:

a 2.85 day cycle matching Algol’s variability

a 29.6 day cycle lining up with the Moon

The ancient cycle for Algol (2.85 days) is just slightly shorter than the modern cycle (2.867 days). That tiny shift may be telling us something about how Algol’s orbit has evolved over thousands of years.

Variable stars were once thought to have been first described in the 17th century, but this discovery pushes their recognition back nearly 3,000 years. It fundamentally changes the history of astronomy! What seems like a superstitious almanac turns out to be a celestial logbook, disguising astronomy within myth. If you’d like to dive deeper, you can check out the full research paper HERE

[stellarluminosity]

The Summer Triangle

The summer triangle is a famous asterism in the northern hemisphere made up of 3 brightest stars from 3 constellations:

Vega (0.03) -a bright blueish star from Lyra the lyre. 26 LY away. (I can really see the light blue from my binoculars!)

Altair (0.77) - the 12th brightest star in the night sky from Aquila the eagle. 16.8 LY away

Deneb (1.25) - from Cygnus the swan. It is dimmest of the 3 even though it is a blue-white supergiant because it is 1500 LY away.

These 3 stars are so bright you can easily spot them in urban skies. From 4N, it can be seen as early as June after midnight rising above the eastern horizon as seen in this picture here, lying on its side. It can be seen all the way till early October. The first constellation that I always see will definitely be Cygnus as its 5 main stars makes up another asterism called the Northern Cross. Then followed by Aquila and lastly Lyra. I'd like to think the lyre's body as a parallelogram. Other than Vega, its other stars are quite dim and with the light pollution I see it clearly with my pair of cheap binoculars.

You can use the summer triangle to find north too!

Starting from Altair -> Deneb-> Vega-> Polaris. The pathway forms a "lightning bolt" pointing to the north star.

Another method involves imagining a mirror image of the triangle and move downwards from the tip of the triangle to find the north star a few degrees west. Honestly, I find the lightning bolt method much easier.

[stellarluminosity]

The Astrolabe

What's an astrolabe? its a celestial calculator, aiding in navigation by locating celestial bodies, finding latitudes of stars or even track celestial events. Basically, it's an old timey Stellarium™. Persian astronomer, Al-Fazari, is often credited with building the first astrolabe in the Islamic Golden Age. During this era, there were significant advancements in astronomy which explains why so many stars have Arabic names. Its usage was eventually phased out in the 18th century when sextants were introduced. Modern astrolabe replicas can be found even today as it is such a fascinating device.

I made an astrolabe to test it out

Well technically not really "made it" more like put the pieces together with glue and laminating paper after I printed out the templates from this website. The makeshift fastening pin was from cooper wires that I use for wire wrapping and I added a straw on the alidade as a sighting hole. It worked out in the end. I did tested it out and I won't say it is super accurate maybe the lowest latitude of the template I could get was 10N while I'm at 4N which could have contributed to its off-ness. Modern day astrolabes use clear plastic for the rete instead of brass with star pointers. So far I know how to tell the time from the stars. Still figuring out how to predict sunrise/set and determining the date using sun.

[stellarluminosity]

THE GREAT Planetary Alignment of 2025

FROM TODAY ONWARDS till early Feb we will be able to see the most planets present in the night sky, a "planet parade"

25 Jan will be the best time to start an hour after sunset:

West: Saturn and Venus will be hanging low & close to each other

East: Jupiter is seen in Taurus near the bull's eye (aldebaran). Mars will be in Gemini. Uranus is there too but cannot be seen unless with a telescope Mercury joins in by the end of February 25-26:

You will be able to catch a glimpse of Mercury (very close to Saturn) but this can be quite tricky because it happens as soon as the sun is setting. It will also be very close to the western horizon.

[stellarluminosity]

Constellation: Centaurus

For stargazers living between the latitudes of 25°N to 90°S, look towards the southern skies for Centaurus as May approaches.

Being the 9th largest constellation, it covers an area of 1060 square degrees. This particular patch of sky has a lot to offer since it is embedded in a splendidly bright and intricate part of the Milky Way. For me, the entire expanse of sky encompassing Scorpio, Sagittarius and Centaurus? *chefs kiss* (There are so many interesting deep space objects to see in Centaurus so I’ll probably talk more about it in another post)

For most of the illustrated star maps, Centaurus was always shown to be spearing or sacrificing Lupus, the adjacent wolf constellation. It is said to represent an ancient pagan festival known as Lupercalia and Centaurus is bringing Lupus to the sacrificial altar, Ara. In Babylonian culture, the constellation was depicted as the Bison-man and associated it with their Sun god Utu. Others relate the constellation to the wise Chiron, mentor of great Greek heroes such a Achilles, Asclepius and Heracles to name a few.

Stars of Centaurus

Its a wonderment to stare at this patch of sky since it contains approximately 281 stars below the mag. 6.5 (the dimmest stars that can be observed by the unaided eye) within its borders. It can be overwhelming but 11 main stars can be joined to resemble the outline of a classical centaur. Only 9 stars have official names recognized by the IAU. I have them labelled in the image above along with the meanings behind those names for a lil trivia. The names are mostly of Arabic and Chinese origins.

It boasts magnificent star clusters and home to the two brightest stars of the night sky. Leading the way are Rigel Kentaurus (α-cen) and Hadar (β-cen) forming the front feet of the centaur. These 2 stars are also an important asterism in navigation as mentioned in a previous post called as “the pointers” aiding in identifying the Southern Cross. Holding the position as the 4th and 10th brightest star in the night sky, α & β-cen blazes at an apparent mag of -0.27 & 0.61. They are hard to miss.

Rigel Kentaurus is a triple star system consisting of:

Rigil Kentaurus itself (α-centauri A) & Toliman (α-Centauri B)- 2 sun-like stars locked in a binary orbit of 79.9 years.

Proxima Centauri (α-Centauri C) – An 11th magnitude red dwarf that needs a telescope to be seen. Famously known as the closest star to our Sun only 4.24 LY away. Only discovered in 1915 since it was so faint. It is an outlying member of the triple star system with an orbital period around 550,000 years!

I must at least mention the Omega Centauri Cluster

That fuzzy spot on the centaur's back is one of the oldest star clusters. Believed to be at least 12 million years old. Almost as ancient as the universe itself. It is also the largest known globular cluster in the Milky Way, estimated to have 1 million stars. This cluster holds many titles along with being the closest cluster to our solar system at 17,000 LY away. With that, it shines as the brightest globular cluster in the night sky.

Identifying Centaurus

There are 2 known patterns for Centaurus as you can see here. The one on the left is official pattern recognized by the IAU. The right side is more commonly used in other star maps or references. When it comes to identifying constellations, its better to stick with anything less convoluted so we'll go for the right side. This version simplifies Centaurus's upper body into a stick figure.

The easiest way to locate Centaurus is by looking for Crux first facing southward. The pointers (α&β-Cent) & Crux are basically a matching set and the fact that they are fairly bright stars make it even easier to locate! Once you got the Pointers, make your way up to Alnair, Muhlifain & Birdun. These are fairly bright stars of mag. 2 that form a right-angled-triangle-lower-body. When you get a hold of that triangle, you're all set! Simply move upwards and try to visualize a stick figure.

Most of the stars that make up the torso are quite dim (mag. 2.5 -4) making it even harder to make anything out of it for beginners. I used to call that area as "a huge mess" It helps to start from Alnair (top of the triangle) and go upwards to the center, Mu & Nu- Cent. Then, upwards to Menkent, a fairly bright orange star of app. mag. of 2.04. From there work your way out to the arms. Same goes for the hind legs. Best time to view the centaur is in May where it is fully upright in the sky in its full glory at 10pm onwards.

Happy star hunting!

[stellarluminosity]

Here's some sunset pictures I took:

Not my usual space posts but the SKY is sort of related to space. I might as well share some sunset pics that I took over the years with my phone.

Other planets can be cool with their perpetual storms or diamond showers but do they have marvelous sunsets like the Earth? Don't think so! It's undeniable that sunsets on Earth are amazing and you'll probably never see anything like it anywhere else in the universe. Let us all bask in its beauty!

And no two sunsets are alike so each time you observe a sunset, know that you'll only be seeing it once! Oh how wondrous the sky can be!

As usual click on the pics for better quality

Location: where I live

[catwinterberry]

˚*•̩̩͙✩•̩̩͙*˚

[spacetelescopescience]

Like a shiny, round ornament ready to be placed in the perfect spot on the holiday tree, supernova remnant Cassiopeia A gleams in a new image from the James Webb Space Telescope.

Webb’s high-resolution look at Cassiopeia A in the near-infrared is adding to the treasure trove of information from the telescope’s recent image taken in mid-infrared light.

The most noticeable colors in Webb’s near-infrared image are clumps of bright orange and light pink that make up the inner shell of the supernova remnant. These tiny knots, comprised of sulfur, oxygen, argon, and neon from the star itself, are only detectable by its Near-Infrared Camera’s exquisite resolution, and give researchers a hint at how the dying star shattered like glass when it exploded.

The outskirts of the main inner shell, which appear as a deep orange and red in the mid-infrared image, now look like smoke from a campfire in near-infrared. This marks where ejected material from the exploded star is ramming into surrounding gas and dust.

Credit: NASA, ESA, CSA, STScI, D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (University of Gent).

[stellarluminosity]

Deep Space Objects: Crux, The Southern Cross

Crux sits in the heart of the Milky Way, making this a wonderful spot for dazzling deep space objects.

Jewel Box Cluster (NGC 4755)

Located at an approx. distance of 6440 LY from Earth, it is regarded as one of the finest open star clusters. It resembles a fuzzy star of mag. 4 to the naked eye. With just a good pair of binoculars, its 4 bright multicolored stars form an A-shaped asterism. One of the main stars is a red supergiant and stands in contrast to the nearby luminous, massive blue stars. They are also referred as the "traffic lights" due to its varying colours. The name was originates from John Herschel's description: "...this cluster, though neither a large nor a rich one, is yet an extremely brilliant and beautiful object when viewed through an instrument of sufficient aperture to show distinctly the very different colour of its constituent stars, which give it the effect of a superb piece of fancy jewellery."

Coal Sack Nebula (Caldwell 99 / C99)

Through the naked eye, it appears like as if someone cut a hole in the star-filled milky way. It does not signify an absence of stars, but rather is formed by thick interstellar dust clouds obstructing starlight from behind. This dark nebula is approx. 600 LY away, one of the nebulae close to us.

In Australian aboriginal culture, the Coalsack is recognized as the head of an Emu and Great Rift that trails all the way to Cygnus makes up the body and legs. Depends on where you are, the emu could be lying on its belly or upright. (Pic) Imagine a floppy yellow rubber chicken.

NGC 4103

One of the less significant open clusters in Crux along with NGC 4349 & NGC 4609. It has moderately bright stars. It is a fairly young open cluster located 5000 LY away from Earth.

[stellarluminosity]

Constellation: Crux, The Southern Cross

Crux may be the smallest out of the 88 constellations but it is certainly not to be passed by. Simple and compact, it is a distinctive cross made up of 4 bright stars. Acrux (α-Cru) and Mimosa (β-Cru) are multiple star systems. The double star to look out for is Acrux which is distinguishable by a telescope revealing twin blue-white stars of magnitude 1.3 and 1.7. The red giant Gacrux (γ-Cru) of mag 1.6 contrasts with the constellations other blue-white stars with its notable reddish hue. The pulsating variable, Imai (δ-Cru), is the dimmest out of the 4 which shines with an apparent mag of 2.8. There is a 5th star, Ginan (ε-Cru) that is not included as part of the cross but crucial when it comes to identifying the cross. With a mag of 3.58, this orange giant star can be snuffed out in light polluted skies.

Like its northern counterpart, the big dipper, Crux can be used as a signpost to find the south celestial pole. It can be quite confusing since any random stars can be used to form a cross in the sky. The False Cross asterism is a common navigation error when 2 stars from Vela and another 2 from Carina was mistaken for the Southern Cross constellation. 4 neighbouring stars from Carina also form another asterism called the Diamond Cross. The key is to always look out for a lil star, ε-Crucis, between Acrux (α-Cru) and Imai (δ-Cru). They are almost in line with each other. Another key element is that Crux will always be accompanied by The Pointers, consisting the stars Rigel Kentaurus (α - Cen) & Hadar. (β- Cen). They are 2 stars of somewhat equal brightness from the constellation Centaurus just east of Crux.

How to find south with Crux and the Pointers

Firstly, perpendicularly bisect the line formed by α & β-Cen and extend the line all the way down. Then followed by a straight line going downwards from γ-Cru to α-Cru. The point where these 2 lines meet will mark the southern pole.

Where to look? (From a perspective of 4°N)

Being a prominent southern hemisphere constellation, those living way down south will see it as a circumpolar constellation meaning it will never set. If you're living in latitudes above 20°N, it will not be visible. In the picture, I've included the "Pointers" as well for ease of identification and orientation. From 4°N, Crux can be seen as early as April at sundown at SSE. Both the Pointers and Crux are fully visible late April. Best time for viewing will be in May where it is high up in the sky when you're facing exactly South (Duh). As July went by, it makes its way towards western horizon. It will not be seen again until January but only appearing in the wee hours of the morning.

[stellarluminosity]

Venus Approaching Greatest Elongation

The “evening star” takes center stage this month and all the way till June as soon as the sun sets. Venus hangs about 25° above the horizon upon sunset and outshines everything other than the moon. Venus will continue to inch higher in the sky with every sunset up to its greatest elongation on June 4th with its highest altitude at 43°. This also gives us about 3½  hours  to observe Venus before it sets every night. Just from observation, Venus blazes with a distinct golden hue at magnitude -4, (a whooping magnitude -4.5 at greatest eastern elongation!)

Venus also passes by the seven sisters from 8th – 14th April. A great astrophotography opportunity for sky watchers. Venus will be closest to the Pleiades on 10th – 11th April, just 2.5° from each other.

Venus is so bright, it is visible even in the dusty twilight sky through the lens of my crappy phone camera. (That lil white dot on the upper right)

[pokeprincess]

The most beautiful thing 🌙✨

[septemberkisses]

There really is such a softness in knowing that you look up at some of the same stars as people who lived 5000 years ago did.