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Message: <blockquote data-quote="typo" data-source="post: 3180806" data-attributes="member: 83808">An interesting question. I don't know the answer for sure but there are several different factors appear to be important. If a single photo receptor in the fovea is around 20 arcseconds lets just suppose you would need a diameter of 5 receptor or 100 arcseconds to distinctly 'see' is as a disk rather than a point. 100/12 would be 8.3 x magnification as a minimum. To see it with optimum acuity the pupil/exit pupil needs to be about 2.5mm so an 8x20 sounds like a starting point, but 10x25, 12x30 or 20x50 would give you increasingly larger discs. Larger EPs reduce acuity and would increase defocus blur.Venus appears very bright even in the night sky, but it's completely invisible in daylight. So it's not technically too bright even at a 2.5mm EP but I think the extreme contrast means the scatter within the retina is the primary cause of the apparent expansion. You could shrink the EP even further with more magnification but another path is to attenuate the contrast. That probably means neutral density filters. I already have objectives masks to reduce the EP and I have some sheets of ND filter material which should do for a little experiment. When I get a chance I'll have a go.David</blockquote>