function over(img) {
	if (img.id == 'orion') {
        img.src =  'sitelayout/imageHeader_1x3_over.png';
    }
	if (img.id == 'bigDipper') {
        img.src =  'sitelayout/imageHeader_2x1_over.png';
    }
}

function out(img) {
	if (img.id == 'orion') {
        img.src =  'sitelayout/imageHeader_1x3.png';
    }
	if (img.id == 'bigDipper') {
        img.src =  'sitelayout/imageHeader_2x1.png';
    }
}

function clickOn(img) {
	if (img.id == 'orion') {
        self.location.href="orion.jsp";
    }
	if (img.id == 'bigDipper') {
        self.location.href="big-dipper.jsp";
    }
}