question ; the op states he wants the longer ffocal length scope for planetary......so why a 100 degree fov? for planets, light transmission ,and clean field, would be better...for planets.
long f ratios are very forgiving of cheaper eyepieces.
Now short focal length telescopes, they require very good eyepieces to deliver good images.
If the scope is not tracking, though, the wider apparent field eyepieces yield longer times between nudges.
That could be a good reason to use wider field eyepieces.
In my 12.5", I have a 110° 3.7mm eyepiece, and I also have a 3mm 62° eyepiece
The former yields a 13.3' true field, while the latter yields a 6' field.
The passage time of a planet through the eyepiece is 53.2 seconds for the former and 24 seconds for the latter, both from edge to edge.
Assuming I nudge the scope to follow the planet when the planet nears the edge but doesn't quite get there, I can go 45 seconds before nudging with the first eyepiece, and only 18-20 seconds on the latter
That makes a big difference in the field and explains why I never use the 3mm on that scope, but why I use the 3.7mm instead.
The point is that a wider field is more compatible with a non-driven longer focal length.
And lest you think that planetary images are poor in the 110°, I note that I have seen white markings on Uranus, and albedo markings on Ganymede with that eyepiece.
Edited by Starman1, 31 January 2020 - 02:44 PM.