Tony Fisher wrote:
Is it ok to ask this? What if they want to keep it private? Some people prefer to keep their real names off the internet.
It is quite reasonable for Andreas, in his capacity of Site Museum Moderator to contact them for that issue, so I have provided contact information to him privately. By registering an email address with the site they have consented to be contacted by the site and its staff.
But in general no, people should only give contact information after checking with the source first. It's just courtesy.