rotation animation xcode iphone - xcode

Question

Im trying to rotate an image around in a circle using a simple single view application in xcode. I have a circle image on the main storyboard and a button. Im using the following code, but the circle image drifts down to the right then back up to the left as its spinning. I'm not sure what it's missing.
Thanks for you help.
ViewController.h
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController
{
IBOutlet UIImageView *theImageView;
IBOutlet UIButton *theButton;
NSTimer *theTimer;
float angle;
BOOL runStop;
}
#property (atomic, retain) IBOutlet UIImageView *theImageView;
#property (atomic, retain) IBOutlet UIButton *theButton;
-(IBAction)runRoulette:(id)sender;
#end
ViewController.m
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
#synthesize theButton, theImageView;
- (void)viewDidLoad
{
angle = 0;
runStop = FALSE;
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)rotateRoulette
{
theImageView.center = CGPointMake(self.theImageView.center.x, self.theImageView.center.y);
theImageView.transform=CGAffineTransformMakeRotation (angle);
angle+=0.001;
}
-(IBAction)runRoulette:(id)sender
{
if(!runStop)
{
theTimer = [NSTimer scheduledTimerWithTimeInterval:1.0/600.0 target:self selector:#selector(rotateRoulette) userInfo:nil repeats:YES];
}
else
{
[theTimer invalidate];
theTimer = nil;
}
runStop = !runStop;
}
#end

Answer 1

I found a very simple way to make my animation work how i wanted it too -
theImageView.center = CGPointMake(160.0, 364.0);
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:5];
//theImageView.center=CGPointMake(self.theImageView.center.x, self.theImageView.center.y);
theImageView.transform = CGAffineTransformMakeRotation(M_PI/2.65);
[UIView commitAnimations];
It spins the theImageView M_PI/2.65 (M_PI/2.65 is the roataion amount) for a count of 5.