Solar Stormwatch was the first space weather citizen science project, the aim of which is to identify and track coronal mass ejections (CMEs) observed by the Heliospheric Imagers aboard the STEREO satellites. The project run four years, with input from >16,000 citizen scientists, resulting in a data set of >38,000time-elongation profiles of CME trajectories, observed over 18 preselected position angles. We present our method for reducing this data set into a CME catalogue. The resulting catalogue consists of 144 CMEs over the period January 2007 to February 2010, of which 110 were observed by STEREO-A and 77 were observed by STEREO-B. For each CME, the time-elongation profiles generated by the citizen scientists are averaged into a consensus profile along each position angle that the event was tracked. We consider this catalogue to be unique, being at present the only citizen science-generated CME catalogue, tracking CMEs over an elongation range of 4° out to a maximum of approximately 70°. Using single spacecraft fitting techniques, we estimate the speed, direction, solar source region, and latitudinal width of each CME. This shows that at present, the Solar Stormwatch catalogue (which covers only solar minimum years) contains almost exclusively slow CMEs, with a mean speed of approximately 350 km s−1. The full catalogue is available for public access at www.met.reading.ac.uk/~spate/solarstormwatch. This includes, for each event, the unprocessed time-elongation profiles generated by Solar Stormwatch, the consensus time-elongation profiles, and a set of summary plots, as well as the estimated CME properties.

Time of CME onset in HI1 FOV: The stated time corresponds to the time of the maximum in the count of Solar Stormwatch profiles used to define the occurrence of an event in this catalogue. See section 4.2.2 in the catalogue paper for more details

The speeds of the CMEs have been estimated by fitting the central position angle of each event with the Fixed-Phi geometrical model. See section 6 in the catalogue paper for more details.

The beta angles of the CMEs have been estimated by fitting the central position angle of each event with the Fixed-Phi geometrical model. See section 6 in the catalogue paper for more details.

The latitudinal width of the CMEs in Heliospheric-Earth-Eequatorial coordinates was calculated according to the method discussed in section 6 of the catalogue paper.

Source region latitude and longitdue (in HEEQ coords). An approximate source region of the CMEs was calculated and is given here in Heliospheric-Earth-Eequatorial coordinates. This was calculated according to the method discussed in section 6 of the catalogue paper.

Number of Solar Stormwatch tracks defining this event. The number of time-elongation profiles, over all position angles, that were used to characterise this CME. These time-elongation profiles were all generated as part of the Trace-it activity.

Number of Solar Stormwatch users who tracked this event. The number of unique Solar Stormwatch users who characterized this CME.