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Originally Posted by ballaratdragons
All you need now Steve is the best of both. EQ mount & track the 8".
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I don't think this EQ mount would do well with the long tube and increased weigth of the 8" Newt. That's the great thing about the Mak. It's v short and not too heavy so it's very stable on the mount.
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Originally Posted by iceman
Interesting results, Steve, and nice report. The difference in aperture seems very noticeable. Would be interesting to read your reports when viewing with the 8" and 12" side by side..
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I've done that a few times too.
On planets there is not that much difference in detail seen unless the seeing is very good. The 12" is quite a lot brighter but in average-to-good seeing it shows no more detail. The increased brightness is obtrusive in average seeing: just more light for the atmosphere to smear around the image. E.g., planet's limb or Saturn's rings look more blurred. I suspect this is why people often comment that smaller refractors give better views of planets than large Newts. A crossed polariser or appropriate ND filter can fix this (better than aperture mask), and the 12" can always give as pleasing a view as the 8".
With a 15-20 degree temperature change, the 8" is close enough to thermal equilibrium to start observing in 5 minutes, the 12" takes 15 minutes or more. Best views are obtained much later after at least 15 min for the 8", and 30-40 min for the 12". This is with baffled fans running.
The 12" is always a big improvement on stars and DSOs. Under dark skies the 8" pulls in lots of DSOs though and showpiece objects will certainly impress newcomers equally in either scope.
The 12" is more cumbersome to collimate mainly because springs sag so all 6 screws are needed in a push-pull arrangement unless you replace the springs. The 12" needs collimating more often.
The 8" is a lot more comfortable to use due to its size. Sitting with your feet on the ground makes a big difference to standing hunched over the EP or sitting on a tall stool high off the ground, especially when you have trouble finding close to perfectly level ground, as I usually do.
The 8" is truely a grab-and-go once you attach carrying handles to the sides of the base (diagonally opposed). The 12" is far from it: base, OTA, and fan+battery+counterweight(s) need to be carried outside separately, so 3 trips at least. (I have to carry everything down a flight of stairs to the backyard.)
The 8" secondary never dews up if the fan is running. (Unbaffled stock fan might not be good enough for this though.) The 12" needs a dew shield for extended observing otherwise the secondary will dew up.