Need help! No smoothed animations.

here there, I wanna make an animated gif of a rotating planet. That rotates 360 ° and then again, so I want it to be looped, but if I add a key at frame 1 with 0° and at frame 160 with 360°. If I playback the animation It will end and start slowly. At the end the animation look worse, I want it to start inmediatly so there will be a nice unending loop in the final gif.
Is this possible and how?

Section Fail!

Ok well for one thing this is in the wrong section. but you can do this. Open the IPO Curve editor. Hit ‘a’ to select all your curves and then select your Curve menu > Extend Mode > and change to Extrapolation.

Hope this helps

Frame 160 needs a degree of 357,75 (a frame with the rotation of 360 degree is the same as 0, this way your animation has 2 repeating frames while looping). And don’t forget to set the IPO of the rotation to linear. Wrong section indeed.