I posted a while ago about looking into the new modular LS100 but in the meantime, the older scopes are on sale right now as a closeout. They have the same package available for the LS50 and LS60, both pressure tuned.
Did Lunt really discontinue their LS50THa and LS60THa scopes? I like to think that I keep my finger on the pulse of the solar scope market, and I completely missed this.
Those are nice pictures Gustavo.
Hmm. But if I'm going to get a larger scope down the road, I probably won't double stack this one. I also looked at the new modular LS60mt and one can get that for $2500 with the B1200 and a white light wedge. Of course, it's missing the $300 mount.
That sort of puts me back where I started because the whole point was not to get in that deep with this scope as I'd rather put the money into the larger scope later.
I also did a little more reading and appears that I cannot upgrade the LS50 to a crayford focuser and again, I don't want to put five hundred more dollars into a feather touch now.
I appreciate all the input. I need to weigh this a little more. 
I started out with the single stacked LS50THa in October 2017, later got a double-stack module in the spring of 2018, and finally upgraded to the LS60THa with 60mm DS module and FT focuser in the spring of 2019. In my experience, both the 50 and 60 have their upsides and downsides.
The 50 clearly has the price advantage, and it's a very, very capable scope for its aperture. The scales fell off my eyes once I double stacked it. I have zero--and I mean zero--regrets about double stacking. But I found that the lesser etalon on the 50 resulted in a well-tuned sweet spot that was just a bit smaller in diameter than the total width of the Sun's disk. But overall, my DS'ed 50 gave me satisfying views of the Sun in a compact, lightweight package.
But there came a point when I realized that I had grown very serious about solar astronomy and wanted to have a richer experience at the eyepiece (I'm strictly a visual observer). Last year around this time I was lucky enough to have an opportunity to visit Lunt in Tucson and try out some upgrade options in person. While I was there, I knew that I had been completely sold on the value of double stacking, and knew I wouldn't consider going back to single stacked mode. So I was intent on testing double-stacked options during my visit.
I was really impressed with the LS80THa even in single stack mode. The sweet spot seemed to cover almost the entire field of view. The contrast was excellent. But there's no going back once you double stack, so I knew I wanted to keep that going with whatever upgrade path I took. I found the internal DS module on the 80 does suffer from some glare issues, and the addition of a high contrast filter took care of them at the expense of dimming the view substantially.
I ended up going with the LS60THa that I tried at Lunt. I also got the bigger 60mm DS module as opposed to the still very satisfying 50mm DS module. The smaller DS module still performed really well, much better than I expected. But since more aperture means better resolution, I opted for the full 60mm DS module.
To my eye, the width of the sweet spot on the LS60THa is bigger than the Sun's disk (i.e., the sweet spot is maybe 120% the width of the Sun's disk), meaning that you get the full benefit of a well-tuned H-alpha view across the whole Sun. But I found (and other's don't seem to have this problem) that the 60 had more background glare than what I remember my 50 had. The 50 had much more of a jet-black background. But the 60 is a really satisfying full-disk scope.
Over the year that I've had it, I've settled in with my LS60THa and have really grown to like that scope. (I describe that scope in fuller detail here.) The addition of a simple ND filter took care of most of the glare I noted here (I describe my experience here). That glare is much more apparent in single-stack mode.
Bottom line: unlike nighttime scopes where aperture is king, the optical systems of H-alpha solar scopes are somewhat more complex. More aperture will give you more resolution, but aperture isn't everything. The etalon is also an important factor to consider. Solar scopes with more aperture will typically have a better etalon, although I suppose that's not necessarily so. Compared to the Lunt 50, the Lunt 60 will not only get you more aperture and better resolution but also a better internal etalon and larger sweet spot. (I raised the question of sweet spot here. Definately pay attention to anything Bob Yoesle says on that thread or any other on this forum.) The 50 is a really, really good starter scope. Indeed, calling it a "starter scope" isn't fair to it, because the 50 is just a plain ol' good scope in its own right. But if you're like me and get hooked on H-alpha solar observing, it won't be long before you want more aperture and a better etalon.
It's nice having the option for a two-speed focuser to really dial in sharp focus, so that's another thing the 60 has going for it.
If you can, I'd skip the cost involved with buying and selling scopes when upgrading and simply go straight for the 60. But I'd also keep in mind double stacking, which is definately not cheap (nothing made with quality ever is) but which adds an utterly enhanced observing experience that is far and away better than single stacked observing especially during these days of solar minimum. I can't stress that enough. Prominences do become somewhat dimmer, but not badly so. The rich contrast that the Sun's disk appears with is breathtaking in double-stacked mode. Single-stacked scopes, especially in the 50-60mm range, won't show that richness in contrast that a DS'ed one will.
If a DS'ed 50mm is too much for you at this point and a DS'ed 60mm is completely out of the question, go for the 50mm in single stacked mode and see how you go. You may find yourself saving for a DS module for your 50 in short order. You have the option to upgrade to the very worthwhile FT focuser for the 50.
If you know you are unable to or will never want to shoulder the expense of double stacking a 60mm Lunt but can swing a DS'ed 50mm Lunt now, I'd go for the latter. There's no question that I'd prefer having a smaller-aperture double-stacked solar scope over a larger-aperture single-stacked one.
If a SS'ed 60mm is within the realm of possibility, if you think you may want to double stack later on (and trust me, you will), and if you want to take it easy at first with this whole H-alpha solar observing business, go for the 60 in single-stack mode. You'll get a scope with a better etalon over the 50, and you'll position yourself well to double stack later on and have yourself a really great solar observing rig when funds become available and if the desire strikes you.
