Nnedi Okorafor’s ‘Binti’ series tells the story of a young Himba woman — a mathematics prodigy from a family of astrolabe-makers — who finds herself caught up an interplanetary war after defying her traditionalist family to attend university. The final volume of this Afrofuturist novella trilogy was released about 3 weeks ago, and much has already been said about the series’ themes, worldbuilding, and storytelling. I am not here to offer another general review, but I do wish to respond to the representation of astrolabes.
To be clear, I am glad that an author I admire has been inspired by an object that has deep significance to me. I’ve even been inspired to imagine what futuristic astrolabes might be like, particularly if created in different cultural or environmental milieux. Yet although I realize that the books are speculative fiction, I cannot help feeling that the word “astrolabe” has been applied to devices so far removed from what astrolabes are that the use of the term feels jarring. Moreover, these devices seem to embody some common misconceptions about astrolabes that I feel compelled to correct.
Chief among these is that astrolabes have never been communication devices. However, the instruments called “astrolabes” in ‘Binti’ are primarily used for making phone calls and leaving messages, and basically seem to stand in for smartphones. The devices are also used as a kind of high-tech passport that store a great deal of identifying data about their owners; they are additionally capable of playing music, displaying one’s current location during travel, or informing parents if their child has wandered outside a certain area. In one scene, Binti’s astrolabe even detects her having a panic attack and verbally guides her to come down from it. These functions, if they cannot already be performed by smartphones (with Internet and the right apps installed), can easily be imagined as future smartphone developments.
I feel some culpability here, because it is a very common practice to compare astrolabes to smartphones when explaining astrolabes to the general public. I used to use this metaphor myself. But I dropped it when I noticed that people seemed to take away that the astrolabe is an “older version” of or a “precursor” to a smartphone, whereas in reality, astrolabes are an entirely different species of object.
The thing is, when people ask me to explain astrolabes, they usually want to know what you can do with one — preferably with a physical demonstration. But that does not convey what an astrolabe is. For unlike a phone — which, no matter how many unrelated apps it has installed, remains a device for making phone calls — astrolabes are not defined by a core function. The similarity between an astrolabe and a smartphone is really quite superficial: both instruments are flat, portable, involve mathematical expertise in their construction, and can be put to multiple uses. Some overlapping functionality exists (e.g. both an astrolabe and a smartphone can tell you the time of day), but this is separate from what defines either device.
The essential, defining feature of an astrolabe is that it is a special kind of model of the universe. It is a physical, portable model in which the positions of the sun and selected stars are projected onto a flat surface, such that their relative positions are mathematically preserved. This reveals numerous relationships that are useful for several operations, particularly telling the time of day or night. But the crucial point is that any usefulness stems from how astrolabes model the universe.
Yet to answer “What is an astrolabe?” with “a portable model of the universe” begs the question: why would anyone want such a model? Symbolic reasons aside (there is a delightful story of someone gifting an astrolabe because he “was not satisfied with giving you the Earth, and so he presented you with [a model of] the highest sphere together with all that is within it” ), it isn’t immediately apparent that such a thing might be useful. This is largely because, with modern technology, we do not need to directly consult the sky; thus, we lack a certain sky-awareness.
Most people can easily grasp the concept of a sundial, because they are aware that the sun’s apparent position changes over the course of the day. Far fewer people realize that the stars also appear to move over the course of each night, and that which stars are visible changes over the course of the year — much less that for any given date and latitude, there is a calculable relationship between the positions of the stars and the proportion of the night that has passed and remains. An astrolabe is a physical representation of such relationships, and it is useful because it lets you input information from your environment (e.g. the position of a star in the sky right now) and receive corresponding information (e.g. how many hours are left until sunrise).
In my mind, a believable futuristic extension of an astrolabe would involve either (1) finding new uses for its existing universe model, or (2) extending the model (e.g. by having different retes and plates for use on different planets). But the devices in ‘Binti’ have dials, screens, and computer chips, and run on “mathematical current” (I am unclear if this is meant to be electrical current, a metaphor for computer code or machine-level logic operations, or some combination thereof). Rather than the universe, they model modern computers; the occasional mention of actual astrolabe parts on these devices (e.g. star pointers) is thus confusing (what are the star pointers for?)
More to the point, I cannot imagine how the astrolabe model of the universe could result in communication. Of all the things that the ‘Binti’ devices do, the only one that I could envision an actual astrolabe doing is storing data about one’s ancestry and identity. This is because, in addition to the celestial data stored on the rete and the terrestrial data on the plates, many astrolabes are inscribed with written information (e.g., astrological and geographical tables, signatures of the maker(s), dedications, scriptural verses, pious assertions, and sometimes even poetry). Furthermore, in cultural contexts where ancestors are associated with stars (I don’t know if this applies to Himba culture, although such concepts can be found in many cultures worldwide), some of that ancestral information could perhaps even be worked into the rete.
Beyond astrolabes, the ‘Binti’ series offers a wonderful sense of atmosphere and wrangles with concerns around cultural contact, communication, identity, and tradition; there is plenty that I liked and found refreshing, especially given my own background and life experiences. I do not wish to misrepresent the series in writing about only one aspect of it. But in the spirit of overcoming misunderstanding and misrepresentation — a theme which the books so compellingly explore — I wanted to say my piece here, for the myriad reasons that astrolabes matter to me.
 Mohamed Abuzayed, David A. King, and Petra G. Schmidl. 2011. “From a Heavenly Arabic Poem to an Enigmatic Judaeo-Arabic Astrolabe.” p.93