Target size
3.2° × 1.0°
Approximate angular span used for planning.
Astrophotography Tools
Target Framing Planner
See how telescope focal length, sensor size, and reducers or Barlows change the framing of popular deep-sky targets before you buy another camera or optical accessory.
Your imaging train
Enter the optical setup.
Sensor presets
Computed camera field
2.81° × 1.87°
Effective focal length: 480 mm
Framing preview
Andromeda Galaxy (M31)
Wide target
Approx. target footprint
Frame width used
114%
Target width divided by camera field width.
Frame height used
53%
Target height divided by camera field height.
Important limitation
This is a planning approximation, not a plate-solved sky simulator.
Target dimensions are approximate apparent angular spans. Real orientation, rotation angle, sensor crop, optical distortion, mosaics, focal-length variation, and how much faint structure you choose to include can change the composition.
Reducers
Wider field, shorter effective focal length
A reducer can help large nebulae and galaxies fit while also changing focal ratio and image scale.
Long focal lengths
Smaller field, tighter targets
Longer focal lengths can frame galaxies and planetary nebulae tightly but make tracking and guiding more demanding.
Mosaics
A target can still work when it does not fit.
If the target footprint exceeds the frame, that may simply mean the object is better suited to a multi-panel mosaic or a different focal length.
Next step
Check sampling before buying the camera.
StarStation's Astronomy Tools page also calculates image scale from pixel size and effective focal length, which helps connect framing decisions to camera sampling.