1 magnitude jumps:
See any popular sizes there?
For 0.5 magnitude jumps, combine the rows.
But I recommend 1 magnitude jumps whenever possible.
It does make me wonder why there are 11", 14.5", 15", 17.5", 18", 22", 24" and 28" sizes.
My guess is that each person has a maximum tolerable size and that sometimes the 1 magnitude jumps are too much to handle.
Well, 1 magnitude makes a profound difference. Any size larger than that will be >1 magnitude, so even more impressive.
8 to 16" is about a magnitude and a half, and a 16" can be moderately portable.
I have adopted the 1-magnitude jump as a good guide rule for getting significant differences - you could argue for .75 or whatever but 1 is hard to deny. I'm still holding at 10" and wouldn't do anything less than 16" if I ever went larger. For sure: going from 4" or 6" up to a 10" scope is a completely different viewing experience and can be easily justified IMO in terms of increase-in-wow-factor while still maintaining relative ease of use and transportability. Beyond that, the size/weight/cost start to become more formidable.
I do think it is a fact that larger scopes can be easy to use. If you don't plan to/need to transport the scope in the first place, that is one case. And, even if you do transport the scope it can be done with the right setup. My benchmark for this is havasman and his 16" dob. He transports and fields it by himself often (ok, he does have a dog with him, too...), but he has the right equipment and physical setup at home: garage, driveway, mini-van-style vehicle with low, long, wide cargo deck, etc. And, yes, that jump up to 16" is a clear next-level of viewing experience over a 10" scope. And, an f/4 16" would even keep both of my feet on the ground for viewing, but...
I have a small shed and don't have enough room to have what I would consider to be a transportable scope (my 10" dob) AND a larger scope that doesn't travel. And, I have garden paths between my shed and my driveway (uneven, not good for rolling/hauling heavy equipment) and a truck with a tall bed that would not allow me to easily load/unload a 16"+ mirror box solo. All that - plus the cost - is keeping me comfortably seated and viewing through my 10" for now. NV aside, it still seems that the biggest gain to be had is still darker sky, which for me means the scope has to be easy to transport.
Edited by WyattDavis, 29 May 2019 - 03:28 AM.