Moving the background image with ccsprite in cocos2d + iPhone

panorama = [CCSprite spriteWithFile: @"blue_drops_2-wallpaper-2048x1152.jpg"];
        panorama.position = ccp( 480/2 , 320/2 );
        [self addChild:panorama];
       
        appendix = [CCSprite spriteWithFile: @"xmas_0020.jpg"];
        appendix.position = ccp( 480/2-1, 320/2 );
        [self addChild:appendix];
       
        // schedule a repeating callback on every frame
        [self schedule:@selector(nextFrame:) interval:.5f];
- (void) nextFrame:(ccTime)dt {
    panorama.position = ccp(panorama.position.x - 100 * dt, panorama.position.y);
    appendix.position = ccp(appendix.position.x - 100 * dt, appendix.position.y);
    if (panorama.position.x < -1709/2) {
        panorama.position = ccp( 1709/2 , panorama.position.y );
        appendix.position = ccp( 1709+480/2-1, appendix.position.y );
    }
}