Forms Authentication redirection

I have configured forms authentication but do not want to use FormsAuthentication.RedirecttoOriginalUrl because my original url is the login page.  Is there a way to create and attach a ticket to a normal response.redirect method.

OriginalUrl - https://www.mydomain.com/login.aspx?certificate=<encrypted query string>

If everything checks out...

Create ticket > Attach it to new redirect to ~\application\main.aspx

Is there a way to accomplish this?
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