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Message: <blockquote data-quote="typo" data-source="post: 3182623" data-attributes="member: 83808">As promised, I had another go with stopping down the objectives and using ND filter to see how the relative size of Venus appeared in the view. To be honest I don't feel I learned a great deal more than that first look.Over the 20 minutes or so I was viewing, the sky got darker and the apparent size generally increased. With the 20x50 it increased from 1/100 FOV to about 1/60FOV. With the use of 3 layer ND filter the apparent size decreased and on both occasions to about 1/600 FOV which is the correct diameter. To cut an uninteresting story short with both a high resolution and low resolution 10x50 the combination of a 25mm aperture and 3ND filters reduced the diameter to less than 1/1000 of the FOV approximating to the real diameter. The shrinkage with the 8x42 appeared somewhat less than the others and was probably about twice the real size but I didn't try anything extra to shrink it further.David</blockquote>