The best place to look for the answer to the first question is Sarma's
incredible catalogue of Indian astronomical instruments (available here:
https://srsarma.in/catalogue.php).

It does not have equatoria as a separate category, it just lists
different types of astrolabes, but it is definitely worth a closer look.

L.

On 31/03/2025 12:54, AJ Misra via INDOLOGY wrote:
> Dear colleagues:
>
> I am asking on behalf of a colleague who is not  a member of Indology
> listserv. I have excerpted his email below.
>
> ──
>
>     I’m writing to kindly ask whether you’ve come across, in Sanskrit—or
>     any other South or East Asian—astronomical or primary sources, any
>     description or reference to an astronomical instrument known in
>     modern literature as an /equatorium/.
>
>     I’m also wondering if you’ve seen any diagrams in Sanskrit texts
>     that depict planetary models enclosed by a graduated ecliptic
>     circle. For reference, I’ve attached two examples of such diagrams
>     from Arabic and Persian sources.
>     image.png
>     image.png
>
>   ──
> I welcome any suggestions/comments on this.
>
> With kind regards,
> AJ
> --
> <https://www.mpiwg-berlin.mpg.de/research/departments/max-planck-
> research-group-astra>
> *Anuj MISRA*, Ph.D (he/him)
> /Max Planck Research Group Leader <https://www.mpiwg-berlin.mpg.de/
> people/amisra>/
> RG: Astral Sciences in Trans-Regional Asia (ASTRA <https://www.mpiwg-
> berlin.mpg.de/research/departments/max-planck-research-group-astra>)
> Max Planck Institute for the History of Science (MPIWG)
> Boltzmannstraße 22, 14195 Berlin, GERMANY
>
> Room 102, Harnackstraße 5
> +49 30 22667 313
> amisra@mpiwg-berlin.mpg.de <mailto:amisra@mpiwg-berlin.mpg.de>
>
> ─ /in conjunction with/─
>
> /Professor of the History of Science and the History of Knowledge
> <https://www.geschkult.fu-berlin.de/en/e/wissensgeschichte/
> mitarbeiter_innen/Anuj-Misra/index.html>/
> Institute for the History of Knowledge in the Ancient World
> Department of History and Cultural Studies, Free University of Berlin
> Arnimallee 10, 14195 Berlin, GERMANY
>
> Room 205
> +49 03 838 59046
> a.misra@fu-berlin.de <mailto:a.misra@fu-berlin.de>
>
> ─
> /Affiliated External Researcher <https://ccrs.ku.dk/staff/?pure=en/
> persons/663586>/ (2024─25)
> Department of Cross-Cultural and Regional Studies (CCRS)
> University of Copenhagen, Copenhagen, DENMARK
> anuj.misra@hum.ku.dk <mailto:anuj.misra@hum.ku.dk>
>
> ─
> /Adjunct Senior Fellow <https://profiles.canterbury.ac.nz/AJ-Misra>/
> (since September 2021)
> School of Mathematics and Statistics | Te Kura Pāngarau
> University of Canterbury | University of Canterbury
> Christchurch, NEW ZEALAND
> aj.misra@canterbury.ac.nz <mailto:aj.misra@canterbury.ac.nz>
>
>
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