Interplanetary Transfer Windows

[katateochi]

What is everyone using these days for working out when optimal transfer windows to other planets will occur?

I'm using @TriggerAu's Transfer window planner mod

And in the past I've used the web app planner which the above mod builds upon https://alexmoon.github.io/ksp/
And then there's the generated transfer alarms from Kerbal Alarm Clock.

But they all give slightly different answers. KAC's suggested times are quite different to those generated by alexmoon's web app and the Transfer Window Planner mod (those are only different by +/- 10 days or so).  Ie right now (Year 1, Day 53), KAC suggests I could transfer to Duna in 49 days (Y1, D103) but the TWP mod suggests waiting for 176 days (Y1, D234).

I guess they say, when at sea take 1 compass or 3, and two of my 'compasses' are pointing in roughly the same direction, so go with them. But in this case both are using the same underlying logic, so really it's more like having 2 compasses, which is the path to madness!
 

So what do you guys use to work out when the best time is to go for IP transfers?

[Superfluous J]

1 hour ago, katateochi said:

What is everyone using these days for working out when optimal transfer windows to other planets will occur?

I'm a huge fan of Astrogator, though you may feel it's cheating.

When I don't use that, I actually do it myself with a maneuver node trick I learned years ago. The fact that I *can* do it this way makes it easier for me to consider Astrogator to be not cheating

 

 

[HebaruSan]

2 hours ago, katateochi said:

But they all give slightly different answers. KAC's suggested times are quite different to those generated by alexmoon's web app and the Transfer Window Planner mod (those are only different by +/- 10 days or so).  Ie right now (Year 1, Day 53), KAC suggests I could transfer to Duna in 49 days (Y1, D103) but the TWP mod suggests waiting for 176 days (Y1, D234).

It's been a while, but I looked into those tools' algorithms when I was working on Astrogator. I think KAC is the least accurate, using just an approximation based on phase angles (plus an option to use a handful of hard-coded pre-computed windows). Alexmoon and TWP both do full porkchop plots, which calculate the details of the full route (well, thousands of full routes, one per pixel of the plot), so they'll be closer to what you can achieve in-game. Definitely put KAC at the bottom of your rank-ordered list of trusted sources.

2 hours ago, katateochi said:

So what do you guys use to work out when the best time is to go for IP transfers?

As for me, I also use Astrogator (obviously), which was inspired by repeatedly setting up transfer reminders for all bodies in KAC and wishing it would do that automatically.

[katateochi]

@5thHorseman, @HebaruSan, ah awesome, thanks guys! That looks just like the sort of thing I'm looking for. New, improved, and looks nicely made! I'll give it a go tomorrow.