Errrrr, not OPTIONS...OPTICS...sigh....
Anyway, the site includes things such as rocket trails and other effects of atmospheric conditions of what we see in the sky and take pic of...
http://www.atoptics.co.uk/highsky/rktr1a.htm![]()
My better half found the site and emailed it to me. I have only glanced at the site but the explainations seem good and in terms even i can grasp...
I'm hampered my the inherently limited male brain but she forgives me my weakenesses and keeps things simple. 

