Is it disrespectful to invite a renowned lecturer if I know that he will be travelling through my city? Actually I am working in an Information Systems Faculty in the main capital of my country. A few days ago I receive an email in which a university located in other city of my country; will have a renowned lecturer to make a small conference for the students in that university. I would like to invite that lecturer for a very brief speak with the faculty and some students, because I know that this professor will arrive first to the capital before moving to the other city.

The question that I have is how can I make him an invitation so that it does not sound disrespectful, because I think it will be a great opportunity for us to have this type of academic contacts. Should I write him directly to his email to see if he will available? or should I travel to the other university to see if I can catch him up after his lecture? The problem with the last option can be that he could be on a rush to return to his country and it will be a missed opportunity.

Any advice?

Thanks
This is a completely fair request, and you can ask her/him without any worries. That said, there are some aspects that you may want to take into account to increase the chance of the speaker actually saying yes:


Please do not just show up at the lecture and ask there. Almost certainly (s)he will have made other plans at this point. Ask in advance, and as soon as possible. This also has the advantage that you are not putting her/him on the spot directly, but give time to ponder the issue.
If possible, use a joint acquaintance to put you in contact rather than cold-mailing her/him. The probability of the speaker actually taking time out of her/his day to speak to your faculty will be so much higher this way than if you are just a random stranger who sent her/him a mail.
Frame the meeting as starting point for collaboration, not just an informal chat. Prominent people tend to not be keen on wasting their time on meetings with unclear outcome, so make sure that you and (s)he knows what to expect.
Relatedly, have a clear agenda in mind and make sure in advance that, should the speaker decide to visit you, the key people that you want her/him to meet are actually available. It apparently happens quite frequently that a motivated individual invites a prominent professor over, and then all the other faculty / students are actually not particularly interested in talking to the guest. As you can imagine, this tends to be embarrasing, for both, the guest and the host.