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The Harry Potter Astronomical Marathon
By Mike Weinstein

Saturday, Feb. 10, 2007 – 40º N latitude

6:03 PM

Tonight, two of my passions – astronomy and Harry Potter – will come together. The challenge I have set for myself: to watch the sky from dusk until dawn, and track down, in a single night, most of the stars and constellations whose names Jo Rowling uses for the characters in her books. A Harry Potter astronomical marathon, if you will. This journal will record my thoughts and observations as the night progresses, especially concerning the connections between the characters and their celestial namesakes.

Supply check: I’ve got my star maps, my binoculars, and my light source (dim red light, so as not to ruin my night vision). On the table next to my lawn chair are an enormous box of Bertie Bott’s Every Flavor Beans and plenty of hot, homemade butterbeer in a large thermos. Jim Dale’s mellifluous voice wafts out of the CD player on the ground beside me – his twelve-hour audio recording of Harry Potter and the Prisoner of Azkaban, just the right length for an all-nighter.

As the twilight deepens, I adjust the zipper on my down parka, pull my Ravenclaw scarf a bit tighter about my throat, settle into my lawn chair, and wait for the stars to appear. Let’s rock and roll.

6:37 PM

The last traces of dusk have faded away, and I look high in the west for my first target: the constellation Andromeda, two curving lines of stars reaching upwards. The figure represents a beautiful princess of Greek mythology; her parents had to give her up as a sacrifice to a sea monster, as penalty for their boasts that her beauty rivaled even the gods’ (not a good idea).1 Her Potter counterpart, Andromeda Tonks (née Black), was also given up by her family, although in her case it was for the heinous crime of marrying a Muggle-born.2

Nearby lies the W-shaped configuration of stars representing the mythical Andromeda’s royal mother, Queen Cassiopeia.3 That name also appears in the House of Black, although there she is not Andromeda’s mother but her… er, let me check my copy of the Lexicon’s Black Family Tree… ah yes, her paternal grandfather’s sister.4

I open up the box of Every Flavor Beans, and munch on a lovely peppermint one. Hope there’s not an earwax-flavored bean in here. Or tripe. I hate tripe.

7:20 PM

High in the south stands the most famous of the winter constellations, Orion the hunter. A rectangle of four bright stars, bisected by three more in a line – his famous belt. Orion is also the name of Sirius Black’s father in Potter lore.5

A line drawn through Orion’s belt to the lower left points to the brightest star in the heavens, Sirius itself. The star lies in the constellation of Canis Major, one of Orion’s hunting dogs;6 for this reason it is also called the Dog Star. Rowling chose this name, of course, because of Sirius Black’s canine Animagus form. One supposes that Orion Black hoped his son would be as faithful to the family name as a pure-bred dog – and when Sirius disappointed his father and ran away from home, you can bet that no “LOST DOG” signs were posted.

Figure 1: All-sky map for observer at 40º N latitude at 8 PM on February 10, 2007. Generated by John Walker’s Your Sky web site (, annotated by Mike Weinstein.

8:11 PM

Back to Orion. Of its rectangle of four bright stars, the one at the upper-right corner is Bellatrix, a Latin word which signifies a female warrior.7 A perfect name for Sirius Black’s cousin Bellatrix Lestrange, the militant follower of the Dark Lord. How unfair that the celestial representations of Sirius and his murderer lie so near to each other in the sky.

Another line drawn through Orion’s belt, this time upwards and to the right, roughly points to the pretty cluster of stars known as the Pleiades, or the Seven Sisters. In Greek myth, the Pleiades were the daughters of the god Atlas.8 Most of them had offspring with immortals as befitted their divine status, and therefore glimmer proudly in the sky borne by their father. Only one married a mortal – the one named Merope. For the shame that this brought to her and her family, her star was dimmed.9 A fitting namesake for poor Merope Gaunt, who brought similar shame to her pure-blood family by running off with a Muggle. Raising my binoculars, I focus on the Pleiades and admire the view – with optical aid one can see far more than seven stars keeping Merope company.

It’s getting quite cold now. Wish I could conjure up blue flames in a jam jar like Hermione. Will settle for hot butterbeer in a thermos. Delicious! And somewhat alcoholic!

Figure 2: Simulated binocular view of the Pleiades star cluster. Generated by John Walker’s Your Sky web site (, annotated by Mike Weinstein.

9:25 PM

Back to Orion again. A line drawn approximately perpendicular to his belt, to the upper left, points towards the constellation of Gemini, the celestial twins. Its two brightest stars are Castor and Pollux. No Castor on the Black family tree, but Sirius’s maternal grandfather was a Pollux.10

Why did the Blacks give their sons and daughters all of these astronomical names? The ancients sharply divided the universe into two parts: the celestial and the terrestrial. The celestial realms were the home of the dazzling stars, the god-like planets, and the pure, crystalline, celestial spheres. The terrestrial globe – this imperfect Earth – was where the muddy, grubby mortals resided.11 One can see why the haughty, pure-blood Blacks (“Toujours Pur 12) would choose to align themselves with the stars.

What an extraordinary jelly bean I just popped into my mouth! Was that… hot fudge sundae? Holy Hedwig, I think I can actually taste the crushed nuts and sprinkles! Much better than the kelp-flavored one I discovered (to my horror) a few minutes ago.

9:58 PM

As the Earth’s rotation shifts Orion and his crowd off towards the west, some more Blacks are ascending in the southeast. The constellation Hydra represents a fearful multi-headed serpent that kept sprouting two new heads every time one was cut off13 (giving Snape an apt analogy for the Dark Arts in Half-Blood Prince14). For such an impressively hideous monster, the stars that make it up are nevertheless quite dim – all except for one, Alphard, whose name means the Solitary One in Arabic.15 Sirius Black’s Uncle Alphard showed solitary support for Sirius by giving him “a decent bit of gold” 16 – and his name was consequently blasted off the family tapestry.

Near the Hydra is the constellation of Leo the lion. Since the lion is the ruler of the jungle, its brightest star was given the name Regulus, meaning the Little King or Prince in Latin.17 A perfect name for Sirius’s younger brother, the favored child who upheld the family honor. (Sirius recalled that his parents believed that “to be a Black made you practically royal.” 18) Can’t you just see Sirius’s parents proudly calling his brother “our Little King” while referring to Sirius himself as “the mangy Dog”? The sky, however, attests to the truth: Regulus’s star is far outshined by Sirius’s.

11:09 PM

Alas! An earwax-flavored jelly bean. Blecch.

12:01 AM

Welcome to Sunday! Rising in the east is the bright star Arcturus in the constellation of Boötes the herdsman, easily found because the handle of the Big Dipper points to it. In Potter mythology, Arcturus Black was Sirius’s paternal grandfather19 (and fans have speculated that his name also serves as the A in R.A.B.).

My feet are freezing! I get up to do a virtual round of Dance Dance Revolution (minus the video game) so I can warm them up. While doing this, I amuse myself by using a stick as a wand and shouting “Expelliarmus!” every so often.20

1:14 AM

Right, how did Bertie get an entire pizza – complete with mushrooms, peppers, and pineapple chunks – into one delicious jelly bean? A confectionary conundrum!

In the north, winding around the Pole Star, is a constellation representing a snake-like dragon: Draco. It seems that Draco Malfoy’s mother, Narcissa, decided to continue her family’s tradition of using star maps as inspiration when choosing baby names. She clearly expected that her son would be sorted into sneaky, snaky Slytherin. (If Ron found that name funny, it’s a darn good thing that Narcissa didn’t decide to name her son Betelgeuse or Nunki or Zubenelgenubi. Hee hee – “Zubenelgenubi’s a booby!” Sorry, I think the late hour is making me punch-drunk. Or maybe it’s the butterbeer.)

One of the stars in the celestial dragon’s head is called Rastaban, meaning Head of the Serpent in Arabic.21 Bellatrix’s slithery brother-in-law, Rabastan Lestrange, has a similar name. (Why did Rowling scramble the letters? Maybe she had a bit too much butterbeer!)

2:27 AM

The third-quarter Moon is rising in the southeast. I gaze at it with binoculars, while pondering the fact that people used to think the Moon (Luna in Latin) made people go crazy and become lunatics, just like “Loony” Luna Lovegood. (She definitely had a bit too much butterbeer! OK, sorry, getting off the butterbeer thing now.)

3:48 AM

Jim Dale has reached the part where Gryffindor beats Slytherin in the final school Quidditch match, and I cheer loudly as they are awarded the House Cup. This wakes my neighbor, who opens his window and sends some curses my way. I attempt to jinx said neighbor with my stick. Doesn’t work. Pity.

4:34 AM

Low in the northeast is a cross-shaped constellation depicting a soaring swan, Cygnus. Sirius’s Uncle Cygnus was the father of Bellatrix, Andromeda, and Narcissa.22 Was his Animagus or Patronus a swan? Did he have a long, graceful neck? Did he sing beautifully in the shower? We may never know.

Why did the last jelly bean have to be tripe?! And why is the butterbeer gone? O woe.

Figure 3: All-sky map for observer at 40º N latitude at 5 AM on February 11, 2007. Generated by John Walker’s Your Sky web site (, annotated by Mike Weinstein.

5:19 AM

Finally! My last target climbs high enough in the southeast for me to find. In the sprawling constellation of Ophiuchus, the Man-Holding-a-Large-Snake-for-No-Apparent-Reason, is a dim star that astronomers call Nu Ophiuchi, but which also has the name Sinistra.23 The word means Left Hand in Latin, 24 apparently because it marks that part of the serpent-holder’s body.25 When Rowling needed a name for the Hogwarts Astronomy professor, she used one belonging to a star, of course. (And it seems that at one point, she was considering Aurora for Professor Sinistra’s first name,26 perhaps thinking of the aurora borealis, or northern lights.)

Near the star Sinistra is the much brighter Jupiter – apparently Professor Sinistra’s favorite planet, judging from all the essays about it she’s given to Harry and Ron. If these binoculars were a telescope (or Omnioculars), I would be able to make out Jupiter’s four largest moons arranged in a line around it: Ganymede, Callisto, Io, and Europa (the one with the ice, not the mice, weren’t you paying attention, Harry?).

6:01 AM

Well, I made it. Jim Dale is just finishing up the final page of Prisoner of Azkaban, and I managed to hunt down most of Rowling’s astronomical inspirations in a single night. The Sun will be up in about an hour, and the sky is starting to brighten over in the east. I catch a quick glimpse of red Mars low on the horizon, and amuse myself by muttering “Mars is bright tonight” 27 in a centaur-like voice. Except that it isn’t very bright tonight. And it’s not really night anymore. Hoo boy, I need some sleep….


Run Your Own Marathon

During the night of February 10, it really is possible for an observer at 40º N latitude (and any longitude) to see most of the stars and constellations that Rowling references in Books 1-6 – although in reality I have never actually done it. There is nothing special about the year 2007 in this regard; the stars repeat themselves every year (although the Moon and planets do not).

Harry Potter astronomical marathons are also possible at other times of year (generally October through March) and from many other locations on Earth (between 70º N and 20º S latitude). However, the particulars of these star tours – the stars’ locations in the sky, the times when they will be visible, the positions of the Moon and planets – may be somewhat different from the ones given in this essay. So if you would like to give this a try, you should use star maps drawn for your date and location to plan things out; one terrific resource for generating such maps is John Walker’s easy-to-use web site, Your Sky.

Not interested in pulling an all-nighter? Or is it not possible from where you live? Well then, walk outside on any clear night, and chances are good that some of these stars and constellations will be in the sky above you. As the months go by, others will come into view. Depending on your location, you can find most or all of them during the course of a year. Again, Your Sky or other star maps will be helpful in tracking them down.

A final note: if you would like to print out the maps in this essay, it is best to save them to your computer, open them in a graphics program, and invert their colors. The resulting black-on-white images will use much less printer ink.

Happy stargazing!


1. Dibon-Smith, “Andromeda,” paragraph 1.

2. Rowling, Order of the Phoenix, 113.

3. Dibon-Smith, “Cassiopeia,” paragraph 1.

4. Bunker, Black Family Tree.

5. Ibid.

6. Dibon-Smith, “Canis Major,” paragraph 1.

7. Gibson, “Star Names,” Orion – Gamma Ori – Bellatrix.

8. Ibid., “Pleiades Mythology,” Genealogy.

9. Atsma, “Merope.” See esp. quote from Hyginus, Astronomica 2.21.

10. Bunker, Black Family Tree.

11. Van Helden, “Ptolemaic System,” paragraph 2.

12. Rowling, Order of the Phoenix, 111.

13. Dolan, “Hydra,” paragraph 2.

14. Rowling, Half-Blood Prince, 177.

15. Gibson, “Star Names,” Hydra – Alpha Hya – Alphard.

16. Rowling, Order of the Phoenix, 111.

17. Gibson, “Star Names,” Leo – Alpha Leo – Regulus.

18. Rowling, Order of the Phoenix, 111.

19. Bunker, Black Family Tree.

20. Noe, “Dance Dance Revolution.”

21. Gibson, “Star Names,” Draco – Beta Dra – Rastaban.

22. Bunker, Black Family Tree.

23. MasterFroggy, “Guide to Stars and Moons,” Sinistra. The author of that work cites an astrology web page (Wright, “Fixed Star: Sinistra”) as a reference. As of this writing, I have not yet found an astronomical source that gives Sinistra as a name for the star Nu Ophiuchi.

24. Lewis and Short, Latin Dictionary, “sinister” def. I.2.

25. Ophiuchus is traditionally drawn with his back to the viewer, so Nu Ophiuchi really does mark the Serpent-Bearer’s left hand, not his right. For instance, see folio 13 verso from Johann Bayer’s famous 1603 book of stellar cartography, Uranometria (archived online by the Linda Hall Library of Science, Engineering, and Technology at

26. Hobbs, “More idle jottings,” transcription.

27. Rowling, Sorcerer’s Stone, 253.


Atsma, Aaron. “Merope.” Theoi Project: Guide to Greek Mythology, 2000-2007.

Bayer, Johann. Uranometria. Augsburg, Germany: Christophorus Mangus, 1603. Archived at the Linda Hall Library of Science, Engineering, and Technology.

Bunker, Lisa Waite, ed. “The Noble and Most Ancient House of Black.” The Harry Potter Lexicon, Which Wizard, 25 November 2006.

Dibon-Smith, Richard. “Andromeda.” The Constellations, 1999-2000.

———. “Canis Major.” The Constellations, 2000.

———. “Cassiopeia.” The Constellations, 2000.

Dolan, Chris. “Hydra.” The Constellations and their Stars.

Gibson, Steven. “Star Names.” . Table of names at

———. “Pleiades Mythology.” The Pleiades.

Hobbs, Belinda, ed. “More idle jottings (Page 1).” The Harry Potter Lexicon, Guide to, 4 July 2006.

Lewis, Charlton T. and Charles Short. Entry for “sinister” in A Latin Dictionary. Oxford: Clarendon Press, 1879. Archived online at the Perseus Digital Library, Tufts. Crane, Gregory, ed.

MasterFroggy. “Guide to Harry Potter’s Stars and Moons.” Master Froggy’s Encyclopaedia of All Things Harry Potter, 2003-2005.

Noe, John. “John Noe performs Dance Dance Revolution.” The Harry Potter Video Galleries. /videogallery/video/show/46.

Rowling, J.K. Harry Potter and the Chamber of Secrets. New York: Scholastic, Arthur A. Levine Books, 1999.

———. Harry Potter and the Goblet of Fire. New York: Scholastic, Arthur A. Levine Books, 2000.

———. Harry Potter and the Half-Blood Prince. New York: Scholastic, Arthur A. Levine Books, 2005.

———. Harry Potter and the Order of the Phoenix. New York: Scholastic, Arthur A. Levine Books, 2003.

———. Harry Potter and the Prisoner of Azkaban. New York: Scholastic, Arthur A. Levine Books, 1999.

———. Harry Potter and the Sorcerer’s Stone. New York: Scholastic, Arthur A. Levine Books, 1998.

Van Helden, Al. “Ptolemaic System.” The Galileo Project, 1995.

Walker, John. “Your Sky.” 18 April 2003.

Wright, Anne. “Fixed Star: Sinistra.” The Fixed Stars.

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