For the past several weeks there has been very intense usage of SkyView by a small number of users which has degraded responsiveness for other users. Most of the requests seem to be coming from virtual machines using Amazon Web Services so we are not clear who or what is causing the issue. The requests seem temporarily at least to have abated but we are looking at options for throttling or forbidding access should they start up again.
We apologize to our users for the recent poor performance and hope to be nimbler in addressing such concerns in the future.
If you are planning on making some large number of SkyView requests you may find that using SkyView-in-a-Jar is more convenient and less intrusive for other users. You download the jar file and run requests directly. This will often be more efficient — e.g., you can generate just FITS files if that is what you want — and allows many custom options not available through the web interface. With the exception of the Mellinger Optical survey, all surveys available on the Web interface can be accessed using SkyView in a Jar.