Sometimes we want star trails and sometimes we don’t. What’s the longest exposure you can use before you start to get a star trail? That depends on your sensor size and the focal length of your lens! This handy chart gives you the answer using the generally accepted ‘500 rule’. 500/(your focal length in 35mm terms).
For a more in-depth discussion on this topic, please read this article HERE.
WTF? Instant means instant, no? “Instant” access to the PDF isn’t chasing to my email to find your email in my spam.
I’m sorry you are unhappy with the experience for receiving your free chart. Unfortunately it’s very hard to send things to people without them ending up in the spam folder, and there’s little we can do about that. All of the data in the chart is also provided on this page, so in the event that it takes a few minutes to arrive, we suggest that people refer to this page. The system which we pay for to deliver these files does do it almost instantaneously, but sadly at that point we are at the mercy of the email services. I’m sorry you had a poor experience retrieving your’s.