<!-- Begin
var how_many_ads = 5;
var now = new Date()
var sec = now.getSeconds()
var ad = sec % how_many_ads;
ad +=1;
if (ad==1) {
txt="";
url="http://www.amazon.com/exec/obidos/ASIN/0810993732/hipsubwhiguy-20/ref=nosim";
alt="America In Space:  NASA's First Fifty Years";
banner="http://www.spaceaficionado.com/america_in_space.jpg";
width="79";
height="101";
}
if (ad==2) {
txt="";
url="http://www.amazon.com/exec/obidos/ASIN/0375754857/hipsubwhiguy-20/ref=nosim";
alt="This New Ocean: The Story of the First Space Age ";
banner="http://www.spaceaficionado.com/this_new_ocean.jpg";
width="72";
height="102";
}
if (ad==3) {
txt=""; 
url="http://www.amazon.com/exec/obidos/ASIN/1904668151/hipsubwhiguy-20/ref=nosim";
alt="A History of Space Exploration by Tim Furniss";
banner="http://www.spaceaficionado.com/history_of_space_exploration.jpg";
width="78";
height="102";
}
if (ad==4) {
txt=""; 
url="http://www.amazon.com/exec/obidos/ASIN/0425179877/hipsubwhiguy-20/ref=nosim";
alt="Failure is Not an Option: Mission Control from Mercury to Apollo 13 and Beyond";
banner="http://www.spaceaficionado.com/failur_is_not_an_option.jpg";
width="70";
height="102";
}
if (ad==5) {
txt=""; 
url="http://www.amazon.com/exec/obidos/ASIN/1904332609/hipsubwhiguy-20/ref=nosim";
alt="50 Years in Space: What We Thought Then... What We Know Now by Patrick Moore";
banner="http://www.spaceaficionado.com/50_years_in_space.jpg";
width="78";
height="102";
}

document.write('<center>');
document.write('<a href=\"' + url + '\">');
document.write('<img src=\"' + banner + '\" width=')
document.write(width + ' height=' + height + ' ');
document.write('alt=\"' + alt + '\" border=0><br>');
document.write('<small>' + txt + '</small></a>');
document.write('</center>');
// End -->
