A unique insight into the earth at night



NOKTOsat Satelite images

Radiance calibrated nocturnal multispectral (RGB true colour) images taken from the International Space Station (ISS).

The images of the earth at night taken from the International Space station are of the highest quality available. These high resolution photographs were taken by astronauts and are in colour, which means they offer a rare view of the earth at night in its true colours. Understandably, many people are under the impression that such photographs already exist due to the famous Black Marble image by NASA. However, the Black Marble image is a collection of black and white photographs to which a fake colour technique was applied, making it an artistic, instead of a realistic representation of the earth at night.

Although the ISS images are the highest colour resolution available, the originals have not yet been scientifically processed. Fortunately, due to a collaboration between the Complutense University of Madrid, NASA and ESA, NOKTOsat is now able to offer a scientific data reduction pipeline for the ISS images. NOKTOsat images are radiance calibrated in three channels RGB corrected by Vignetting nonlinear response of the cameras and other technical features that need correction in order to have images of scientific quality.

Noktosat images are ideal for tracking human activity globally. All of the following fields have at some point benefitted from the use of black and white nocturnal satellite images. Now, Noktosat offers satellite images in colour that provide far more quality data than what was previously available.

Some examples of uses are:

Geographical studies - Population estimation, Land use, Cultural difference

Economical studies - Tracking economic activity, GDP estimation, Poverty assessment, Oil production

Environmental studies - Energy efficiency, Air pollution, bio diversity protection, Illegal fishing, Sky brightness estimation, light pollution, Co2 level estimations

Human health - Cancer research, Mosquito related illnesses

Safety and security - Civil safety, Monitoring disaster areas

Policy making - regulations for light pollution, construction, traffic safety)

Commercial purposes

Big data analysis


About us

NOKTOsat is a spinoff from the Cities at Night project and resulted from more than 20 years of research in advanced scientific instrumentation and astrophysics. In order to assist in light pollution research carried out by the Complutense University of Madrid, NOKTOsat developed software that produces full radiometric calibrated images. These calibrated images have been essential to research collaborations such as the Cities at Night project involving NASA, ESA and various research institutes.

NOKTOsat images have contributed to internationally acclaimed research that has been published in high impact scientific journals. We are convinced that the knowledge obtained through our calibrated images is valuable to society in general. Therefore, we want our data to be easily accessible to the public. Furthermore, in order to make future research in the field of light pollution sustainable, part of the profit of this company will go to further research projects focused on understanding the impact of artificial lighting on the environment.




Complutense University of Madrid

After an impressive 500 years of research in astronomy carried out by the Complutense University of Madrid, it officially founded the astrophysics department in 1987. Although, light pollution was not considered a serious research field until recently, for five decades  it has already been an important parameter when testing potential sites for high altitude observatories. The Complutense very own observatory was planned in the nineteen twenties when light pollution was not an issue. However by the time it was build, light pollution had increased dramatically and with the fast growth of the Madrid metropoly the observatory is now one of the most light polluted observatories in the world. This disadvantage turned into an advantage for our research in light pollution. Since 1994 the observatory has continuously been used for light pollution research. In 2007 we began to research light pollution using satellite images of the earth at night in addition to the sky brightness measurements we were taking on the ground.

Many pioneer programs have been developed during the Complutense´s light pollution research since 1994. For example; the citizen science projects ´NixNox´and ´Cities at Night´, the EU project ´Stars4all´, the TESS photometer and the REECL (the Spanish network of light pollution studies). In addition to initiating and leading many pioneer programs in the field of light pollution the Complutense university has also participated in some of the most crucial light pollution research in the world such as the new world atlas of artificial light at night and the LONNE network of European researchers in light pollution.


CEGEP of Sherbrooke (GRAPHYCS)

As part of an environmental study Noktosat images were used during the streetlight planning of the city of Montreal.


GFZ German Research Centre for Geosciences

GFZ has been using Noktosat images for research purposes mainly focused on land use and the monitoring of the evolution of light pollution.


IS Global Barcelona Institute for Global Health

IS Global is using NOKTOsat images for epidemiological studies in cancer research.


Universidada De Santiago De Compostela

USC is using NOKTOsat data for advising the regional government of Galicia on light pollution control.


Savestars consulting

Calle Palencia 1
Las Rozas 28231, Madrid, Spain

+34 619 358 685


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