Gooday David,
In astronomy we usually only speak of angular size, which is the angle of an arc of a circle and then absolute size can be worked out from this formula.
absolute size = distance * tan(angular size)
Or you can work out the length of the circumference by using 2*pi*distance and then divide that length by 21,600 to give you the length of 1 arcmin. So if your angular size of the object was 5 arcmin then multiply your result by 5 to get absolute size.
Clear as mud
Bill
Last edited by billdan; 24092016 at 10:41 AM.
