As any popular science reader knows, when traveling between Earth and Mars, there's a Hohmann transfer opportunity about every two years (I believe it's every 26 months, specifically).
What I've never understood or seen mentioned, what is the reasonable realistic window for that - as actually used in practice by NASA, Rosaviakosmos, CNSA, ISRO, ESA, etc.
So. You're getting ready to do a Hohmann transfer (in either direction). Do you have only a matter of minutes? Hours? Days? A couple of months?
Are there some practical examples of past launches?