Tricks to make it to Duna?

[Rayquaza]

Hey KSP! After a long time, I finally decided to launch a ship to Duna (manned, of course. I can't risk my unmanned probes ) I wanted some help landing on Duna. The most trouble I seem to get is to get an intercept to Duna by Hohmann transfer. What is the ideal relative position of Kerbin and Duna, to get a nice trajectory? Also, are 19 radial drogue parachutes, 9 radial parachutes, and 1 main parachute enough for landing?

[Snark]

For the launch window, there are some good planning tools out there; my personal favorite is http://ksp.olex.biz.

As for the parachutes: it totally depends on your ship design. However, in general, the solution to landing on Duna is generally not to spam parachutes; it's just not efficient use of mass. My own preferred choice: add just a couple of drogues and a small number of regular chutes.  That's enough to slow down to a few dozen meters per second. Then use a brief burst of retro-thrust to slow down just before impact.

It only needs a smidgeon of fuel, which weighs much less than tons of parachutes.

[Gojira1000]

Spaceplanes are a nice option as well, for Duna - then you only need a pair of chutes for final stopping power.

[bewing]

To find a nice transfer window, the first thing you need to do is to be able to approximate it by eye. Then you can refine it.

So: the first nice thing is to accept a contract early that asks for sending a probe on an escape trajectory out of Kerbin. Once it's in orbit around Kerbol you can set up test maneuver nodes on the probe to find good transfer windows.

The second thing is that your window will happen approximately when Kerbin's tangential velocity is pointing right at Duna. (I find that it actually happens just a bit before that.) So that's when you start looking hard for a window.

And I agree with Gojira1000 about spaceplanes -- you can have even more fun if you don't put on any chutes and land the jet vertically on its rocket engines.