This dataset contains photographs taken by an all-sky camera located on the roof of the Receive Cabin (51.145168°N, -1.439750°E) at the National Centre for Atmospheric Science (NCAS) Chilbolton Atmospheric Observatory (CAO) in southern England, UK. Photos are taken at 5 minute intervals on a continuous basis in order to record general atmospheric conditions.

The camera is an AXIS M3027-PVE network camera, which is alternatively known as an AXIS 0556-001. In the frame of reference of the photos, the angular field of view is 187° in the horizontal and 168° in the vertical, i.e. essentially covering a hemisphere. The centre of the field of view is nominally directed towards the zenith, although it is not known with what level of accuracy. The azimuthal alignment (measured in degrees from North), ϕ_AZIMUTH, of each part of the photo can be estimated from the relationship:

ϕ_AZIMUTH = 280 - ϕ_PHOTO

where ϕ_PHOTO is the angle measured (in degrees) clockwise from the the 12 o'clock position in a polar coordinate system whose pole is at the centre of the photo. Note that ϕ_PHOTO decreases as ϕ_AZIMUTH increases. Details of how this relationship has been derived can be found in the publication available from https://doi.org/10.5281/zenodo.8096680 .

The camera synchronises its internal clock with Coordinated Universal Time (UTC). This clock is used to trigger the capture of photographs and to produce the time stamps used in the file names. For a reason that is not entirely clear, there is typically a 1 s delay between the time stamp shown in the overlay at the top of each photograph and the one used in the file name. Although the time stamp shown in the overlay is assumed to be the more appropriate one, it is not computer-readable without making use of image processing software. Consequently, the time stamp from the file name has been adopted as the official one and recorded in the embedded metadata.