As part of an on-going project, I have to calculate the Angular Diameter of the moon. This is to be done using a digital SLR Camera. I have some pictures, as well as some calibration images (a ruler a fixed distance away). I am pretty sure I need to use the formula:(adsbygoogle = window.adsbygoogle || []).push({});

[tex] plate scale = \frac{s}{\theta} [/tex]

where s is a fixed measurement on the image, and theta is the angle from the lens to either side of s of the actual object.

Therefore I need to work out the angle to the ruler (see diagram), and use that and the pixel size of the ruler to calculate the Plate Scale. then use plate scale and pixel size of moons diameter to calculate the anbgular diameter.

Does this seem right?

Also, does theta have to be in radians or arcminutes? (I think its arcminutes)

TFM

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# Just Checking - Calculating Angular Diameter of Moon

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