Feild of view and size calculator

Field of view

Focal Length (mm): Barlow x
Width of Film/CCD (mm):
Height of Film/CCD (mm):

Field of View (W):
Field of View (H):

Size of object (in pixels) for CCD/DSLR

Resolution of Sensor:

Angular Diameter of Object
Degrees: Arcmin: Arcsec:

or select object

Pixels per degree: per arcminute: per arcsecond:
Arcseconds per pixel:


Graphical Representation of size


This calculator can be used to help plan an astrophotography session when using prime focus with or without a barlow lense. Above you can calculate the field of view after entering in the focal length of a lense or telescope and the width and heigh of the CCD/Sensor/Film for your camera. Below that you can calculate the size an object in pixels. The size calculation includes a graphical representation to demonstrate the scale of the object which shows a moon by default, and changes between the moon and jupiter as the moon or jupiter size selections are used or you can click on the image to cycle through available images. To calculate only the field of view you only need to fill in the values above the line. To calculate the size of an object you must fill in the fields above and below the line. This calculator is provided as-is with no guarantee that it is accurate. Please feel fee to contact me if you have any questions or encounter any problems (my contact information is at the bottom of my main site).

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