Manifold Reckoner Item in Manifold Sky | World Anvil

Manifold Reckoner

The Manifold Reckoner is a name-brand, mass-produced, portable navigational aid produced by Pikitora Optics under contract from the Navigator's Guild. The device, while heavier than a magnetic armillary or other such full-sized navigational tool, has the advantage of combining several of these tools into a single, relatively easy to carry package.

Mechanics & Inner Workings

The Manifold Reckoner has undergone several iterations in the past to incorporate a variety of functions useful for the Navigator on the move. The device appears to be a large, extended set of binoculars with a sturdy metal casing; this shell may be comprised of brass or polymer, but particularly expensive versions are made of Eudoxium for reduced weight. A tripod mount is affixed to the base of the device to allow for stationary observations.   Two carousels of stubby, cylindrical housings are mounted in front of the binocular portion, closely resembling an ophthalmological device in models where they are mounted abreast. These cylinders contain telescoping lenses, gimbals, scintillation screens, prisms, and more depending on the specific version of the device. The most current model of the Manifold Reckoner, as of the year 10,000 AR, include the following features:  
  • Binocular/Telescope: Most Manifold Reckoners retain the function of regular binoculars with adjustable zoom levels. Because the grip portion of the device is actually a species of microscope, however, the magnification must be handled by cylinders in the carousels. Each eye can be focussed and zoomed independently, and users often practice interpreting different signals from each eye to prevent vertigo.
  • Spinthariscopes: The Northern and Southern Tesseracts are defined by being both the poles of the Manifold Sky's geomagnettic field and the fact that they experience seasonal fluxes of extraterrestrial charged particle radiation. These particles strike a phosphorescent screen in the spinthariscope cylinders of the Manifold Reckoner, creating visible scintillations. When combined with armillary readings (see below), this information can help the Navigator determine whether he or she is located in one of these polar regions and, if so, which one. This element has the additional benefit of providing warning of dangerously radioactive environments, such as contamination from shardleaf bioaccululation. Manifold Reckoners often contain more than one such device jacketed with different protective materials. The level of penetration through these materials helps the userto differentiate between alpha radiation and beta radiation, as well as the relative intensity of the radioactive source.
  • Spectroscope: The sun and moonlight of the Distal Tesseract trends towards the extremes of the visible spectrum, shading into infrared and ultraviolet, while the ambient light of the Medial Tesseract is most bright in the middle of the human-visible range. Using the spectroscope in the Reckoner's carousel along with this knowledge, a Navigator can determine how close he or she is to either of the aforementioned tesseracts.
  • Miniaturized Magnetic Armillary: Scarcely more than an inch across, the miniaturized magnetic armillary found in one of the right-hand carousel tubes is nevertheless useful to a Navigator for determining the direction of the nearest magnetic pole. Tiny patterns of radium paint beneath the glass gimbal's surface allow it to be read in darkness, while the transparency of the gimbal allows the user to check its orientation against that of the user in local space.
  • Miniaturized Leveling Ball: Similar in proportion to the magnetic armillary (see above) and found in a tube on the left carousel, the miniaturized leveling ball is a surveying tool used by the Navigator to both gauge his or her orientation in space relative to the nearest gravitational field and, near the ground, to gauge the relative flatness of the surrounding terrain. While not always as obvious, the distinction between the Dorsal and Ventral Tesseracts is one of geological activity, with the former being known for its unusual flatness and the latter being known for its extreme heights. The levelling ball features a set of lines similar to those found on attitude indicators on aircraft, but executed on the transparent ball's surface in radium paint to allow use in dark conditions. An additional set of fine lines runs parallel to the equator on the ball, allowing a user peering through it with the knowledge of an object's distance and a little bit of geometry to gauge its height. This ball is weighted so that it always remains parallel to the nearest cube face; it is somewhat less useful in inflection layers and commissures where the forces of gravity balance out to create regions of microgravity.
  • Rangefinder: The rangefinder on a Manifold Reckoner uses optical principles to help the user gauge the distance of objects. It is typically a coincidence rangefinder, as this is easer to fit within the housing, but binocular setups are also possible. The rangefinder is useful in combination with a variety of the other tools found on the device because it enables important geometric calculations to be made. For example, using the rangefinder in combination with the levelling ball allows the Navigator to gauge the relative size of distant objects, while using it with the magnetic armillary allows him or her to gauge the speed and heading of vehicles.
  A popular add-on for a Manifold Reckoner is a protective leather case that helps keep dust out of the mechanisms and scratches away from the lenses when not in use. While not technically part of the Manifold Reckoner propper, these cases often include barometer and hygrometer insets on a free surface to provide an extra bit of useful information for the Navigator. The Eastern and Western Tesseracts are defined by their aridity and humidity respectively. While most Western regions feature extensive standing water, this can sometimes be hard to gauge from low altitude due to rough terrain or construction (i.e. parts of the Blue Silk River). Taking the measure of local atmospheric moisture can help a user unfamiliar with the local landmarks estimate their location in the Manifold or, if he or she already knows, to make meteorological predictions for mission planning purposes.


While extremely useful for a trained operator, a Manifold Reckoner still falls short of being that most taboo of items among Guild members: a fully automated navigational system. For Pikitora Optics, calls to modernize the Reckoner with new features must be continually balanced with the risk of threatening the Guild's bottom line in the event that the tool becomes too easy for the uninitiated to use.

Item type
Navigational Aid / Instrument
Owning Organization
Manifold Reckoners are fairly common among Guild-associated Navigators - the class of people most likely to have a use for the tool, opportunity to use it, and the understanding required to make proper use of its features. However, scientists, civil engineers, and adventurers will sometimes acquire Reckoners for their own pursuits, and some of the features of a Reckoner (i.e. the spinthariscopes, see Mechanics & Inner Workings) are useful as educational aids. In any case, most people who own a Reckoner don't carry spares, as the remarkable precision of the device makes it much more expensive than the sum of its parts.

Cover image: by Pexels


Please Login in order to comment!
5 Dec, 2022 13:45

Very well thought out device! I can imagine it being that expensive given all the stuff that is added to it :p

Feel free to check out my Orena 'Raitin Bane' page and my new world Terra Occidentalis if you want to see what I am up to!
5 Mar, 2023 15:32

What a lovely, inspiring concept. I have never tried to expand my worlds into more technologically advanced eras, but this really wants me to try it!   Has this world ever seen an inversion of the magnetic field and if it did/could happen, would an ancient spinthariscope still work if it was built for a different era when the magnetic field was different?   P.S.: Best of luck in the WAWA, from a fellow competitor :)

Yours truly, Nino.
I am participating in and excited for Summer Camp: check out my pledge here! (psst, its a link)
To learn about my world click on this link! (if you want to ;) )
7 Mar, 2023 05:41

Thanks, and best of luck to you as well!   As for your question, scientists in the Manifold aren't aware of any such inversions, but evidence would be hard to find in any event. Because the Manifold is a hollow, five dimensional cube, most of the magma pockets beneath the surface are disconnected from one another and, thus, it's hard for scientists to gauge how their movements collectively contribute to the geomagnetic field. The plate tectonics of the Manifold are also weird because they're cyclical, churning everything together over long enough periods of time; evidence of shifts might be found in deep ore veins, but few such deposits remain undisturbed on a geological timescale.   Artifacts like Uxmat's Armillary do suggest that the orientation of the geomagnetic field has remained more or less static since at least the end of The Curved Time. If the magnetic poles were to invert, however, the seasonal shifts in the charge/composition of polar particle radiation would also invert. Alpha and beta radiation penetrate materials differently, and the Manifold Reckoner capitalizes on this feature to distinguish between them. Thus, the spinthariscopes found in an ancient Manifold Reckoner would give the opposite of the usual results due to the different materials in their filtering jackets.

Come check out The Manifold Sky: Five-Dimensional Dieselpunk Action   My Current challenge article - Summer Camp 2023 - is now live!
7 Mar, 2023 06:15

And here I went thinking my toroid shaped planet was extreme in terms of wacky fantasy science!   Thanks for the excellent response ^^

Yours truly, Nino.
I am participating in and excited for Summer Camp: check out my pledge here! (psst, its a link)
To learn about my world click on this link! (if you want to ;) )