[Leica] Thirteen reasons I don't miss the east coast

[abridge at mac.com (Adam Bridge)]

In ?Sky and Telescope??s most recent issue there?s an article on shooting 
landscapes and starry skies. They gave a thumb rule I?ve never known:

The max exposure time is (500 / lens focal length in mm) to minimize star 
trails.

So for a 50mm lens it?s (500 / 50) = 10 seconds.

It?s an interesting article with a follow up next month.

Adam Bridge

> On 2015 Aug 18, at 12:11 PM, Philip Forrest <photo.forrest1 at gmail.com> 
> wrote:
> 
> The star images have a small amount of drag from the rotation of the
> earth due to my shooting on a static tripod. I've since made a hinge
> tracker and might be able to capture some better images tonight at lower
> ISO, longer exposure with less or no drag, if the wind isn't too high. 
> 
> Thanks all,
> Phil Forrest