Exposure timings

adree · Post by **adree** » Thu Oct 30, 2003 1:30 pm

Hi,

Does anyone know how long u can leave the exposure open before the stars start to trail with a normal camera without any scopes?

and

how long before trailing on a non guided scope?

adrian

Grievous · Post by **Grievous** » Thu Oct 30, 2003 3:45 pm

I'll say let it open for less than a min and a half to 2 mins at Zoom = infinity, f/ = smallest. Normally, a 35-70mm lens will show some trails at 3 mins and above. As always. i'll encourage you to try different exposure times to give a feel of which timing is suitable for you.

Charlie

ChaosKnight · Post by **ChaosKnight** » Thu Oct 30, 2003 6:50 pm

There is a formula to give you an idea.
The maximum exposure in seconds for film is 700/fl.
For stars near the equator, maximum is 500/fl.

These are based on the tolerance level of 0.05mm per star trail.

This is assuming you don't have tracking.