Astrophotography
Astrophotography Calculators
Use our free online calculators to work out your best exposure times and other key numbers for your gear.
-
NPF Rule Calculator
Work out your best exposure time for sharp stars with our free calculator
Read guide -
500 Rule Calculator
Use our free calculator for the 500 Rule for exposure time
Read guide -
Focal Ratio Formula and Calculator
Use our free focal ratio calculator to work out how fast your telescope is
Read guide -
Messier Planner: Your Free Astrophotography Planner
A free astrophotography planning tool, built by its creator Tom McCrorie.
Read guide