Are NFT stars getting too hot?
How rare is a star?
Star-naming space enthusiasts have recently paid 0.5, 1, and 2 ETH trading Astro Ledger NFT star cards, leading to some excitement — but also a lot of questions. With billions of stars out there, what makes a specific star card worth something to a collector? (To get up to speed, first check out our introduction post, “Funding space grants with blockchain star naming.”) TLDR; each Astro Ledger trading card is mapped to a real star (or other astronomical object), so to understand how special your card is, you have to understand that star’s place in our galaxy.
That’s why we made a guide to help you learn how to identify the rarest and most awesome stars in Earth’s neighborhood. In other words… a crash course about stars!
Here we will explain the important star features that the Astro Ledger team are particularly excited about (though it’s too early to know which properties the collectors are after):
- Brightness — can you see the star in the sky?
- Location in the sky/zodiac — is it in your favorite constellation
Coming soon: - Type of color/size — those rare blue supergiants are pretty!
- Distance from Earth — will James Webb discover signs of life there?
- Number and types of exoplanets — particularly for stars near Earth!
- Miscellaneous features — is it pulsating? moving fast through interstellar space?
- Given name — does it have an important cultural history?
1. Brightness: Can you see the Thumb Star without binoculars?
There are many interesting stars that you’ll need a telescope to admire, but about five thousand of them can be seen with the naked eye. A star card collector might like to actually look up and and gaze at the star they named without any equipment which means first they’ll need to know two things:
- Is the star bright enough to see?
- Where in the sky is it located? (skip to #2)
Star brightnesses are measured relative to the fifth brightest star in the sky, Vega. The brightest star, Sirius, is between three to four times brighter than Vega, but basically all other stars are so, so much dimmer that everyone uses a logarithmic (log) scale to rate their comparative brightnesses. The numbers on this scale are referred to as the star’s “magnitude” and smaller numbers are brighter.
In the log scale chart below, a difference in magnitude of 1 represents a change of about 2.5 times in brightness. All of the very bright stars on this chart are extremely rare, as there are only a hundred or so really bright stars below 2.5 in magnitude.
(“On chain” means that an Astro Ledger trading card already exists for the star, and “not launched” means that no card exists yet but one may be launched soon.)
If you would like for your star to be visible from a suburb without a telescope, you would need a star below a 3 in magnitude. But there are only 173 stars that bright! They are barely visible on the left side of the chart below, but these bright stars are easy to locate in the sky due to their brilliance and typically prominent positions in constellations. If you don’t mind venturing out of the city to see your star, there are 518 stars with a magnitude below 4, still quite visible in good conditions. When we consider all stars technically visible to the human eye in the best of conditions, there are about 5,000 stars to choose from (all with a magnitude below 6).
During Astro Ledger’s initial card releases back in 2018, we first launched the brightest stars from the Ceti (“whale”) constellation. It seems that collectors are indeed favoring these bright (and therefore much rarer) stars. And since you asked, the Thumb Star can definitely be seen without a telescope since it has a magnitude of 4.08 — pretty bright!
2. Location: Can you see the Thumb Star from Thumb Island?
Just because a star is really bright, that doesn’t mean you can see it! That’s because some stars are only visible in certain parts of the world. You will need to keep this in mind when adding star cards to your collection, in case you want to see your star from home.
There are 88 constellations designated by the International Astronomical Union (IAU). Thirteen of them are in the zodiac, so famous they even have their own Unicode characters! Zodiac constellations are great because they are visible from pretty much anywhere on Earth, unlike many other constellations that are only visible in the northern or southern hemispheres.
There is a lot of variation here in rarity of stars per constellation, for example there are 105 visible stars in the constellation Centaurus but only five stars in the constellation Caelum. A few constellations in particular are interesting just because their names are really cool, like Microscopium (microscope), Cetus (whale), Camelopardalis (giraffe), Monoceros (Unicorn), or Volans (flying fish). Please reach out on Twitter, Telegram, or Discord to share which constellations you want to go on chain next.
The first Astro Ledger star cards were for the brightest stars in Cetus and Leo. (Astro Ledger went live in July 2018, a Leo month!) But many visible stars — including from the zodiac constellations — are not yet on chain, as shown by the unfilled rectangles in the chart below. Almost all these stars need names!
Here are the counts of visible (under 6 magnitude) stars in each constellation:
(‘Centaurus’, 105), (‘Taurus’, 97), (‘Eridanus’, 94), (‘Cygnus’, 84), (‘Ursa Major’, 83), (‘Puppis’, 82), (‘Sagittarius’, 79), (‘Hercules’, 78), (‘Draco’, 76), (‘Cetus’, 74), (‘Hydra’, 71), (‘Orion’, 65), (‘Carina’, 64), (‘Boötes’, 63), (‘Ophiuchus’, 61), (‘Vela’, 61), (‘Virgo’, 60), (‘Pegasus’, 58), (‘Cassiopeia’, 57), (‘Scorpius’, 57), (‘Leo’, 57), (‘Perseus’, 56), (‘Aquarius’, 56), (‘Pisces’, 53), (‘Andromeda’, 52), (‘Gemini’, 51), (‘Aquila’, 50), (‘Cepheus’, 50), (‘Lupus’, 46), (‘Camelopardalis’, 46), (‘Monoceros’, 45), (‘Canis Major’, 41), (‘Serpens’, 41), (‘Auriga’, 41), (‘Lynx’, 36), (‘Aries’, 33), (‘Lepus’, 31), (‘Cancer’, 30), (‘Grus’, 30), (‘Capricornus’, 29), (‘Pavo’, 28), (‘Libra’, 28), (‘Lacerta’, 26), (‘Columba’, 25), (‘Vulpecula’, 25), (‘Lyra’, 24), (‘Canes Venatici’, 24), (‘Octans’, 24), (‘Phoenix’, 23), (‘Sculptor’, 22), (‘Corona Borealis’, 21), (‘Tucana’, 20), (‘Coma Berenices’, 20), (‘Musca’, 20), (‘Telescopium’, 20), (‘Piscis Austrinus’, 19), (‘Crux’, 19), (‘Ara’, 18), (‘Corona Austrina’, 18), (‘Microscopium’, 16), (‘Antlia’, 15), (‘Norma’, 14), (‘Canis Minor’, 13), (‘Hydrus’, 13), (‘Triangulum Australe’, 13), (‘Fornax’, 13), (‘Corvus’, 13), (‘Circinus’, 13), (‘Horologium’, 13), (‘Delphinus’, 13), (‘Scutum’, 13), (‘Triangulum’, 12), (‘Leo Minor’, 12), (‘Dorado’, 12), (‘Pictor’, 12), (‘Reticulum’, 11), (‘Ursa Minor’, 11), (‘Chamaeleon’, 11), (‘Apus’, 11), (‘Indus’, 10), (‘Mensa’, 10), (‘Sagitta’, 10), (‘Pyxis’, 10), (‘Volans’, 10), (‘Crater’, 8), (‘Equuleus’, 6), (‘Sextans’, 6), (‘Caelum’, 5)
The Thumb Star and all the other stars in Cetus are just inside the southern sky and visible from places with latitudes between +70° and −90°. Thumb Island is way up north in New Brunswick, Canada at about +45° in latitude, so the Thumb Star is visible from there but is seen not as high up in the sky as it would be from somewhere further south.
Be informed
The next bit of this crash course will be about the size/color of stars and their distance from Earth. Be the first to know when we publish the next post, when new star NFTs are released, and other updates about what’s cooking — and if you have questions or comments, please join the community or reach out to us on:
discord, twitter, telegram
and we even have an old school mailing list you can sign up for.
Thank you so much for being with us on this star naming adventure! Jonathan, Aleeza and Tony.
* Source data on stars from David Nash at astronexus, many thanks! https://github.com/astronexus/HYG-Database
