# BTA-6

*Observatory*

Special Astrophysical Observatory, Zelenchukskaya

| | |
| --- | --- |
| Where it is | 43.6500° N, 41.4400° E |
| State | RU |
| What is done there | optical observatory |
| Main mirror | 6 m |
| Still working | yes |

Test ranges, observatories and ground stations are a hand-picked list kept in this project rather than a published catalogue: no catalogue answers which of the world's thousands of observing sites belong on a map of it. The article below is what lets the choice be argued with.

## What it is

The BTA-6 is a 6-metre (20 ft) aperture optical telescope at the Special Astrophysical Observatory located in the Zelenchuksky District of Karachay-Cherkessia on the north side of the Caucasus Mountains in southern Russia.
The BTA-6 achieved first light in late 1975, making it the largest telescope in the world until 1990, when it was surpassed by the partially constructed Keck 1.

## Elsewhere

- This place on the live map: https://www.orbitalmap.space/?at=43.65,41.44
- The article this row is vouched by: https://en.wikipedia.org/wiki/BTA-6
- Every object: https://www.orbitalmap.space/o/
- What this site is and what it reads: https://www.orbitalmap.space/llms.txt

## Where this came from

Compiled 2026-09-17. Selected by hand for this project. Description from Wikipedia (en). Description: CC BY-SA 4.0.