and the following are plotted in the histogram in Figure 2. The analysis is extended in Figure 3 which plots the histogram counting the number of archives versus the [*archive etendue*]{} ($A\Omega\,A$). Based on this factor, the most productive facilities to date are VISTA-VIRCAM, Blanco-DECam, VST-OmegaCam, CFHT-MegaCam, Subaru-SuprimeCam, VLT-VIMOS and INT-WFC. Quite many near infrared (NIR) instruments populate Figures 1 and 3 due to their fast cadence of images explained by short exposure times and very rapid readouts compared to the other instruments in visible.\
Most exposures are shorter than 80s, probably owing to the fast cadence of NIR instruments and other fast time-domain science, as one can observe the histogram in Figure 4. This makes [*Mega-Archive*]{} and data mining very appealing for asteroid science, as most targets should have stellar-like aspect (instead of longer trails) which results is easily measurable astrometry and photometry.\
The number of images as a function of the observing time when they were obtained is shown in Figure 5. The great majority of the images in the actual [*Mega-Archive*]{} were collected since 2005. The last two years show lower numbers due to later ingestion in the collections and proprietorship which make last images invisible to 