Kitab Latitude Station: Uzbekistan's Pole-Watching Outpost
How a station on the 39°08′ parallel near Shakhrisabz logged 250,000+ latitude readings to track Earth's wobbling pole, and what it does today.
On 14 November 1930 observers at a new pavilion outside Kitab, in what was then the Uzbek SSR, began measuring pairs of stars as they crossed the meridian close to the zenith. It was the start of a series that would run for more than half a century and add over 250,000 latitude readings to a global data set. The question behind it sounds absurd: does a fixed observatory's latitude change? It does, by a fraction of an arcsecond, because the Earth's rotation axis wanders across its surface.
This post follows that relay from a riverbank in what is now Turkmenistan to a satellite beacon in a field near Shakhrisabz. It draws on two papers from a 2000 International Astronomical Union colloquium on polar motion (one by US Naval Observatory historian Steven Dick, one by three Ulugh Beg Astronomical Institute researchers) plus the satellite agencies' records.
Why astronomers went looking for a wobble
In the 1880s two astronomers working apart noticed the same irritating thing. Friedrich Küstner in Berlin, using observations he began in 1884 to measure the constant of aberration, found his numbers only made sense if the latitude of his telescope was changing; he announced the effect in 1888. Seth Chandler at Harvard had noticed in 1885 that his measured latitude for Cambridge, Massachusetts, kept shifting, but judged the idea too bold to publish. By November 1891 he had more data and announced a period of about 427 days, some 40% longer than the figure Euler's theory predicted for a rigid Earth.
If the pole really moves, every star catalogue, every longitude and every clock correction carries a small error. So the geodesists organised. At the Internationale Erdmessung's 12th General Conference, held in Stuttgart in October 1898, they agreed to finance four stations, all on the same parallel of 39°08′ north: Carloforte in Italy, Gaithersburg in Maryland, Mizusawa in Japan and Ukiah in California. Sharing a parallel meant all of them could observe the same star pairs. The International Latitude Service (ILS) began regular observations in September 1899. Cincinnati, on the same line, offered to cooperate. So did Russia.
Chardzhou: the first Central Asian outpost
The Russian contribution came through the Tashkent Astronomical Observatory, founded in 1873 to fix the coordinates of Central Asian towns. Its director from 1890 to 1900, D. D. Gedeonov, already had the right tool: a Wanschaff visual zenith telescope that reached Tashkent in May 1893. Between 1 July 1895 and 1 September 1896 he measured the latitude of Tashkent with it.
Tashkent itself is at about 41°20′, though, too far north. The 39°08′ line crossed the Amu Darya at Chardzhou (the papers spell it Tschardjui; the city has been Turkmenabat since 1999), so that's where the station went. It got Gedeonov's instrument, smaller than the ones at the four funded stations: a 68 mm objective and 87 cm focal length, against 108 mm and 130 cm elsewhere. The Ehgamberdiev paper says building began in July 1898, while its own table lists the regular ILS series at Chardzhou as 29 August 1899 to 25 May 1919.
The site had a problem no lens could fix. It stood about 3 km from the river on sandy ground, and the Amu Darya shifts its bed. By 1908 the water had crept up to the instrument, and it was moved to the right bank. Observations carried on there until the Civil War in Central Asia stopped them in May 1919. In about 20 years Chardzhou sent the ILS more than 35,000 instantaneous latitudes. Dick's station table, adapted from an older summary, has the series running to 1920, a one-year disagreement we can't settle from the sources we've read.
Kitab takes over the parallel
The Tashkent observatory also chose the replacement site: ground near Kitab, the district town just north of Shakhrisabz. The station sits at 39°08′40″ north, within half a minute of arc of Chardzhou's latitude, and more than three degrees of longitude further east. An operator page for the site's astro-tourism programme puts it about 2 km from Kitab town, beside the Kashkadarya on its left bank, and says it was established in 1928; neither of the academic papers gives that date, so treat 1928 as the operator's account. Both papers agree on November 1930 for the start of observations.
Kitab inherited Chardzhou's Wanschaff telescope and its Strasser-Rohde pendulum clock, but the main instrument was new. Over the decades the station worked through this sequence, with the reading counts its own staff published in 2000:
| Instrument | Aperture | In use from | Readings contributed |
|---|---|---|---|
| Wanschaff zenith telescope (at Chardzhou) | 68 mm | 29 Aug 1899 to 25 May 1919 | 35,000 latitudes |
| Askania-Werke (Bamberg) zenith telescope | 110 mm | 14 Nov 1930 | 127,000 latitudes |
| ZTL-180 zenith telescope | 180 mm | 17 Aug 1957 | 73,000 latitudes |
| Photographic zenith tube (moved from Pulkovo) | 250 mm | 1978 | 50,000 latitudes plus 46,000 clock corrections |
Add up the three Kitab rows and you get the paper's headline figure: more than 250,000 instantaneous latitudes for the ILS, and over 285,000 across a century once Chardzhou is included. (The abstract dates the two visual zenith telescopes to 1929 and 1957, a year earlier than the table for the first one; the paper doesn't explain the gap.)
The network around Kitab didn't stay still. Gaithersburg closed for economy in 1914 and reopened in 1932, Cincinnati dropped out for good in 1915, and Carloforte stopped from 1943 to 1946 because of the war. Kitab, by its own institute's account, kept observing through the whole ILS period. In the Second World War, Pulkovo's astronomers were moved to Tashkent, while Kitab took in the evacuated Simeiz observatory from Crimea. Professor G. N. Neujmin, one of the senior astronomers who worked with the Uzbek institute and the station in that period, named asteroid 1351 Uzbekistania in memory of it.
From starlight to satellites
By the 1980s optical latitude work was being overtaken. Dick's timeline shows the International Polar Motion Service starting in 1962, and laser ranging and radio interferometry improving accuracy by an order of magnitude in the 1980s. On 1 January 1988 the International Earth Rotation Service replaced the IPMS as well as the Earth-rotation section of the old time bureau. The station table in Dick's paper closes the classic ILS series in 1984.
Kitab's answer was to become a ground station. The sequence, from the institute paper and the agencies' records:
- November 1991: a beacon for France's DORIS satellite tracking system went onto the roof of the station's administrative building.
- August 1992: a GPS receiver went in beside the pavilion of the visual zenith telescope, with data sent out over INMARSAT-C.
- 1992, 1994, 1995 and 1998: Kitab was one of six permanent stations in the German-led Central Asian Tectonic Sciences (CATS) programme, which estimated movement at about 40 sites in the Pamir and Tien Shan.
- 1995 to 1998: it took part in the German PRARE tracking project.
- Since 1994: its GNSS receiver has been part of the International GNSS Service network as station KIT3.
The DORIS antenna has moved twice. In 2001 it went from the roof to a pillar for better stability, and then the trees grew. A newsletter the International DORIS Service published about a year after the move describes how branches progressively masked the sky, so that by 2015 Kitab's orbit-fit residuals averaged 6.1 mm against the usual 3–4 mm. A move was decided in 2013. The new antenna, named KIVC, sits about 200 m southeast of the GNSS station and was commissioned on 15 June 2016. The blocked share of its sky view dropped from 16.9% to 3.6%, and the agency then ranked Kitab among its best stations. You can read the account in IDS Newsletter no. 4.
The GNSS side is still live. The IGS network page for KIT3 lists it at 622.6 m elevation, gives equipment records back to 1 October 1994, and showed data uploaded on 6 October 2026 (last checked: October 2026). About 60 km south, on Mount Maidanak, a satellite laser ranging system has operated since the mid-1970s, so this corner of Kashkadarya has hosted several space-geodesy techniques side by side.
Our take on why it matters
Uzbekistan's astronomy story usually stops in 1420s Samarkand, with the great meridian arc at the Ulugh Beg observatory site. That's fair; it's the more spectacular ruin. But the Tashkent institute that runs Kitab carries the name of the astronomer-sultan, and Kitab is the thread connecting him to modern geodesy. In our opinion it's the better place to understand what precise positional astronomy actually involves: patient, repetitive night work feeding a shared international record. One station's numbers meant little alone; combined with Mizusawa, Carloforte, Ukiah and Gaithersburg, they traced the pole's path.
It is not for everyone. There's no grand architecture here, and much of the interest sits in old instruments and the story behind them. If you want tilework, stay in Shakhrisabz.
Visiting: what's announced and how to arrange it
In August 2022 the state news agency UzA reported a press tour organised by the Ministry of Tourism and Cultural Heritage with the Kashkadarya regional administration. According to that UzA report, the observatory had been opened so tourists could look at planets and stars, a 3D cinema was showing astronomy films, and an astropark and a geopark were being organised. The report also claims more than 2,000 hours of clear sky a year, a figure we haven't been able to check against a climate source. Treat all of it as announced plans: we haven't found a recent official update confirming which parts are running in 2026.
Two tour operators' pages currently describe guided visits, telescope viewing and a display of old equipment. It's still a working Academy of Sciences research site, not a walk-in attraction, so we'd only go with a visit arranged in advance:
- Base yourself in Shakhrisabz; Kitab is the next town north on the Samarkand side. Our Shakhrisabz day-trip planning covers the road over the pass from Samarkand.
- Ask a licensed Kashkadarya tour operator or your Shakhrisabz guesthouse to book the visit and confirm what's open, particularly any night-sky session.
- Ask before photographing instruments or antennas.
- We haven't listed prices or opening hours because we found no official source that publishes them; check before you go.
If you're continuing south rather than back to Samarkand, the province's capital is covered in our Karshi and Kashkadarya notes, including the Kitab geological reserve in the hills east of town. The underlying history is in the Ehgamberdiev, Eshonkulov and Litvinenko paper, published as “Kitab as One of the Five Stations of the ILS”.