prospectus vs indendure?

what is the difference? they both legal document setting out bond conditions.

They’re different documents. As you say, they both outline the details of the bond issue.

so what is the difference?

http://www.investinganswers.com/financial-dictionary/bonds/indenture-agreement-970

prospectus is basically what is presented to investor as marketing material, and indenture is basically the terms and conditions of the loan agreed.