So my question is why is there such a preference for say a Lunt 80 versus a Coronado 90 assuming double stacking on either. I try to rationalize its just the price difference but many suggest go with a 100 if you can afford it so that appears to crush that theory. I ask because I plan on getting a dedicated scope and as much as research and advertising makes me lean to the Coronado 90DS I have to weigh the talk on this forum as a major deciding factor. After all users trump advertising and numbers 90% of the time!
Between 80mm, 90mm and 100mm, I would say it's mostly splitting hairs in terms of resolution relative to seeing that even permits the limit of the resolution to be realized. It's also not a brightness thing inherently because you can have a lower transmission etalon system and blocking filter with a larger aperture and still have a lower transmission system than something with a smaller aperture potentially that has a higher transmission etalon system and blocking filter. There's variation in the copies and they're not all equal, but some of them are at least held to a standard to at least perform at a base level. You also have to compare if you're wanting a double stack compared to a single stack and whether you're imaging or visual or both.
The Lunt systems tuners are near the focuser, so you don't have to have a custom rigging system to operate the tuning system while looking through the eyepiece or standing on your tippie-toes while staring at a laptop LCD. The Solarmax III series on the 90mm size scope, the tuners are on the etalons at the front of the scope, both tuners and the tilt mechanism. Not everyone can reach them while looking through the scope. That's something to consider (there are work arounds but we're talking about making a custom rig just to adjust the tilt and tune, etc).
The Solarmax III etalons are all front mounted, which is ideal for full discs. The Lunt etalons are not all front mounted in each model. It has to do with angles and dimming of the limb on a full disc, if you care about that (some do!)
The tuning systems are also something to consider. Solarmax III is rich tuning and Lunt uses pressure tuning. They're a little different mechanisms. Most of the information I've seen in reports lean towards saying that the Lunt pressure tuning has a more uniform effect. I can't really speak to that. And there's very few solarmax III users and examples at the moment to compare to, unlike the Solarmax II series. If nothing has changed, that would be unfortunate because when you compare a good Lunt pressure etalon to a Solarmax II rich view etalon the Lunt seems to have better uniformity in most of the examples I've looked at. Again, may just be anecdotal evidence on my biased behalf. But it's worth exploring and researching.
I think the biggest concerns I would have right now is support and availability of parts. Lunt supports their products locally. You can get parts and double stack and get all kinds of stuff from Lunt. Coronado is owned by Meade. You cannot buy Solarmax III etalons right now separately, only as a package, so if you don't double stack right away, can you ever? There are blocking filters available, only. Nothing else is even an option it seems? I could be wrong there. But worst of all, Meade is going bankrupt after major lawsuit stuff. Not sure what their future is or what the future of the Solarmax series stuff is. I would not be comfortable with a $7k scope that may lose any support for in the future. But I may just be worrying too much about it. Still, it's worth knowing about and looking into perhaps.
I would go Lunt 80 double stack with the biggest blocking filter. If you can afford a Lunt 100 double stack, by all means, go for it. Or the new 130 triplet. Or the 150! Those etalons get way more expensive as they get larger.
Edited by MalVeauX, 17 January 2020 - 04:55 PM.