Do not buy by sampling alone
Seeing, guiding, focus, tilt, optical correction, sensor characteristics, mount behavior, processing, and target size matter. Use image scale and field as framing tools, not a guarantee of resolution.
How to interpret the image-scale result
Pixel scale is a planning number
The calculated arcseconds per pixel describes sampling, not a guarantee of final detail. Local seeing, tracking accuracy, optical performance, and processing all influence what a finished photograph resolves.
Field of view controls framing
A longer focal length narrows framing; a larger sensor generally widens it when other variables remain equal. Compare the field to your target object and check whether the optics illuminate the chosen sensor.
Validate the full imaging train
Reducers, Barlow lenses, camera adapters, and corrector spacing can change the effective focal length or useful image circle. Measure the equipment as configured rather than assuming a catalog label.