Imaging window
Find the usable part of the night.
Intersect target altitude time with astronomical darkness and the intended exposure cadence.
Purpose and method
What this calculator does
How long can I image this target tonight? Intersect a target altitude interval with available darkness.
In words: Latitude, declination and altitude limit determine the geometric hour-angle window.
Change a value and the result updates immediately. This geometric planner does not yet model a specific date, horizon profile, Moon separation, weather or meridian-flip downtime.
Working geometry
Altitude and darkness window
The usable imaging interval is the overlap between target altitude and astronomical darkness.
Inputs
Site, target and darkness
Calculated now
Usable window
- Above altitude limit
- 10.47 h
- Usable dark window
- 8.00 h
- Complete exposure blocks
- 96
- Target geometry
- Rises and sets through limit
Governing equation
In words: The altitude limit determines a symmetric hour-angle interval from site latitude and target declination.
Show the working
The calculator applies the equation above to the values currently entered, without rounding until this display.
- Above altitude limit
- 10.47 h
- Usable dark window
- 8.00 h
- Complete exposure blocks
- 96
- Target geometry
- Rises and sets through limit
This geometric planner does not yet model a specific date, horizon profile, Moon separation, weather or meridian-flip downtime.