Free planning tools · Plan an imaging night

Astrophotography integration-time planner

Plan accepted frames, attempted exposures and session duration across filters or nights.

No account needed. Results update here as you change the inputs. Measurements stay in this tab unless you choose to share a link; shared links contain the inputs, including any location coordinates.

Your inputs

The starting values are examples. Replace them with your own measurements, prices or documented requirements.

What to have ready
  • Desired retained hours and sub-exposure seconds for each row.
  • Readout and dither overhead per attempt.
  • Expected rejection and the usable imaging window.
Measurements for Astrophotography integration-time planner
Acquisition plan

Calculated from your inputs

Your plan

The example will calculate here when JavaScript is ready.

What to do next

    Calculation details

    Inputs used in this result

    Compare a change before committing

    Keep this plan, change the inputs and see the difference. The comparison stays in this tab.

    Can the exposure plan fit inside the imaging window?

    Retained integration and time spent outside are different budgets. This integration-time calculator works backwards from desired retained hours, rounds frame counts up and includes your rejection and per-attempt overhead assumptions.

    Add separate rows for filters or sessions. Keep one plan, then change exposure length or rejection assumptions to see the effect in the browser. It is useful for explaining an acquisition schedule without suggesting that equal exposure totals guarantee equal image quality.

    How to use this planner

    1. Enter each filter or session with its retained-hours target.
    2. Set rejection and per-frame overhead from your own experience.
    3. Read the attempt counts and session margin, leaving additional time for setup, focus and slews.

    The calculation

    Accepted frames = ceiling(target seconds ÷ exposure seconds). Attempts = ceiling(accepted frames ÷ (1 − rejected fraction)). Session duration = attempts × (exposure + overhead).

    A worked example

    Two hours at 180 seconds needs 40 accepted frames. With 10% rejection, plan 45 attempts; at 10 seconds overhead that takes 2.375 hours.

    Example inputs are demonstrations. Replace them with your own measurements, prices or documented requirements.

    Assumptions and limits

    Rejection is an estimate, not a guarantee. Frame counts round up. Retained integration is calculated from the required accepted frames, while session duration budgets attempted frames. Add slews, focusing, filter changes, meridian flips and weather delays separately. This plan does not predict signal-to-noise.

    Questions about this calculation

    Why can the retained-hours result be slightly above the target?

    You cannot capture a fraction of a frame in the entered plan, so the accepted-frame count rounds up. Multiplying that count by the exposure duration gives the actual retained total.

    Does using longer frames always reduce the whole session?

    It can change per-frame overhead, but the assumptions and rounding matter. The tool does not model image-quality differences, weather losses or whether the longer exposures are technically usable.

    Put the result in context