Originally Posted by sopticals
I might have a "little dig here".
Why do folks prefer a 22 megapixel camera over a 4 megapixel one????
Having experience with apertures 30mm(1960) to 838mm(2016), I have to say Aperture Does Matter. If it didn't, I would still be happy with 30mm.
My current stable (see signature), includes 4"(102mm), 14"(356mm), 25"(635mm) and 33"(838mm) apertures. I have owned a bunch of 6", 8", and a 12" dobs and newts, and find viewing through anything less than about 12" is like peering into the focuser wearing dark glasses.
Maybe I am an "apertureaholic", (well, yes I must confess I am).But, I make no apology, its a fact. Started with making my own 6-7"mirrors when I was a youngster. After going from 30mm to 76mm(my first reflecting telescope[commercial Japanese]) it was wow! when pointed it into the night sky. Same with my first homebuilt 6" (like doubling the pixels), wow!, and same through each size increase.
Did a "head to head to head" very recently, (14",25",33") dobs (forget the 4" refractor). Subjects Moon, Jupiter, Mars, Saturn. At this point in time neither 25 or 33 have mirror coatings (so tested in "skinny dip form").
The pixel analogy works well as the apertures were compared. The 25" and 33" so far as fine detail on Luna "smoked" the 14" so far as the detail sharpness is concerned. Even when magnifications were matched.
Again take the pixel analogy. When an subject/object/image is captured in a 2 megapixel camera (I had one once), and you blow up the image by a large amount, (take for instance a 2" aperture telescope at 250x), all that happens beyond 25x per inch(where all info that aperture can give you is available,) (50x), beyond that the visual image is just stretched, and when stretched far enough becomes blurred and a pain to look at (empty magnification), BUT, increase the aperture (pixels) and the same 250x in a 25" aperture (10x per inch as compared to the 125x per inch with the 2"aperture). The difference is like "day and night".
I have aperture "as my friend" and like to maintain a large exit pupil and so can avoid the eye floaters that occur for most around the less than 1.5mm. Prefer to keep magnifications in larger scopes at 12x per inch, 2mm exit pupils, to provide, bright sharp images. I feel I don't require to use more than 12x per inch to access full information from a 25" scope. [I am still able at 71 years able to resolve naked eye some of Luna's larger craters when positioned on the terminator, (not difficult when the moon is well placed at sunset or sunrise, before flaring is a problem).]
On the planets, Jupiter (now lowering in my N West [evening]), 25" and 33" showing more than 14", (even as uncoated optics). Didn't get to use 33" on Mars and Saturn due to too much elevation for my current ladder (have to organize a suitable viewing platform, (even though the 33" is f4.1-don't know how folks manage with 36"f5 Obsessions and similar). Again 25 over 14 was"no contest". The smaller scope showed the Martian features, but not as sharply as the 25. (BTW with the 25 being f3.8 I only need a couple of steps on the small ladder to access the zenith). At the time of the 25 v 33 shootout (Jupiter),was watching an upcoming occultation of Io, so was watching this small sphere (easily resolved by both scopes) approach the Jovian limb. It was two steps up the 33 and down over to the other scope (no ladder needed), back and forth until the moment of occultation (happened whilest at the focuser of the 25- was beautiful).
Saturn: even though the 14 easily was able to show Cassini division, planet banding, planet shadow on the bands, the extra aperture of the 25 "aced it" with its superior resolution.
Pic: comparing 3" with 33" (mirror sizes).
Stephen
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