Use your own measurements
Free astrophotography calculators and planners
Check camera framing, optical spacing, guiding and power before you buy, then plan the frames and darkness window for a real night of imaging.
Get results in the browser, explore a change against a saved plan and share the current inputs when you want someone else to check them. Each page explains the method, assumptions and a worked example. No account or file download is needed.
Check equipment compatibility
Backfocus spacing calculator
How much spacing does your camera train still need?
Build your imaging train, then see the spacer gap between your optical reference plane and camera sensor.
Telescope camera field-of-view calculator
Will the target fit the camera frame at this focal length?
See the angular frame of your camera and compare it with simple target outlines or your own target dimensions.
Pixel scale and sampling calculator
What does a camera or focal-length change do to image scale?
Compare two camera and telescope combinations against the seeing range you expect.
Telescope eyepiece comparison tool
Do the eyepieces in your shortlist offer useful different views?
Compare magnification, exit pupil and approximate true field for an editable eyepiece shortlist.
Guide-scope image-scale calculator
What does an entered guiding error mean at the imaging camera?
Compare guide-camera and imaging-camera scales without turning one ratio into a universal compatibility rule.
Plan an imaging night
Astrophotography battery runtime calculator
Will the telescope battery last through your planned night?
Add the equipment you actually run and estimate both runtime and the rated energy needed for your session.
Imaging-session storage calculator
Is there enough working-drive space for the session and processing?
Budget raw image storage, calibration frames and backup copies before a night of imaging.
Astrophotography integration-time planner
Can the exposure plan fit inside the imaging window?
Plan accepted frames, attempted exposures and session duration across filters or nights.
Darkness and Moon planning calendar
Which nights offer dark time with the Moon below the horizon?
Find astronomical darkness and dark intervals with the Moon below the horizon for up to 31 nights at your chosen location.
Calculations run locally in your browser. Sharing creates a URL containing your inputs, including any location coordinates; share only the details you want others to see.