So, I need some advice... practical and to avoid aperture fever to the point of impractical and inconvenience of use.
I'm getting very curious about a visual-only reflector. I have a 8" F6 quartz reflector that I use for visual right now. I use it manually on an alt-az mount with a refractor as its co-pilot. I have a C8 Edge HD that lives on my EQ mount in my observatory. I'm mainly thinking of getting a larger aperture for visual-only use for myself but also for others, my kids, and outreach with the local club. While I realize a 12" dob is inexpensive for the aperture, I really do get hung up on the idea of tracking. I don't even really care much about GoTo. I care more about tracking. The reason being, I use my scopes manually now and I definitely do not like slowly nudging, hand pushing, and constantly readjusting to be able to view something at more than low power. I am spoiled I guess by my C8 Edge on EQ mount where I can point it at a subject and it will stay on it and I can just observe instead of fiddling with adjustments. I live under a dark sky, so I already appreciate what I can see even with these modest apertures. So this has me thinking... a bigger visual instrument, but, I really want it to have tracking so that I can put it on a target and let it just sit there and spend more time observing, and others can observe, without having to chase things constantly so we can just observe.
So knowing the above context, there's a few things I'm curious about and considering.
Practical difference between a 12", 14" & 16".
I think I read the magnitude jumps and going from 8" to 12" is one, and then going to 16" is the next. So the 10" and 14" are the "in between" options that give a little more, but not quite a full magnitude step. So I'm curious what this translates to in real world with respect to visual. Primary subjects would be galaxies, clusters, a few nebula, planets. Namely, at what point under a dark sky can we really truly see the arms on a galaxy like M101, especially someone who is not a skilled observer at outreach, so they're seeing a galaxy and not just the idea of one might be there as a bright smudge. I realize the weight goes up significantly with the size of mirror here. I'm not especially fond of a huge complex heavy setup (which is why I have an observatory and permanent setup at home). So I'm leaning a lot more towards the 12" and 14" categories due to this. But, if 16" truly makes a difference in how much of a galaxy (the arms) one can see, this is still an option.
There are equatorial platforms to hold any dob. And there are computerized tracking dobs. And then there are Equatorial tracking mounts in general. I'm not sure where to go with this. I want it to be as simple and portable as possible for such a large size. I already have an EQ mount in my observatory on a pier. But I realize they are not ideal for visual with where the eyepiece can end up. Also, an EQ mount to handle a 12" or larger reflector is substantial even though the scope itself can be inexpensive, so that just seems less practical. So really maybe its between an Equatorial Platform and then just put a dob on it, or a computerized tracking dob itself. These are commercially available, but I have no experience with how good these motor systems are and if they will truly handle it and last enough years to be worth it. I know EQ Platforms also have a limited time of tracking then must be reset and start again, which is kind of not that attractive with outreach having to fiddle with something. But I'm not sure there, maybe someone can elaborate on that process more. So ultimately it seems more attractive to just look at a tracking computerized dob mount to begin with, the commercial stuff like from Skywatcher/Orion, etc.
I'm also especially interested in whether or not these various mount options like the tracking dob mounts can handle more than a 50mm RACI on the bigger scope. I really like the idea of putting a ST80 on there as the finder too. But this may not be an option I understand.
Portability and Setup
This is another big factor. I went towards observatory fast because I quickly tired of setup. Taking my EQ mount out, assembling, aligning, etc, then putting the scopes on, balancing, etc, was just annoying. Physically not a problem. But I'm a slave to convenience and it was just terribly inconvenient. So I'm very anxious about the idea of a complex or long "setup time" on whatever system I may get into here. If I can move the base. Plug in the controller or power. Seat the scope and it's good to go, I would be happy with that. I realize I'm going to have some setup time. But, this totally means I'm not at all interested in a scope that I have to assemble trusses or any other stuff like that. I would much rather move a 50lb tube and put it in a 50~75lb base. Then again, I would rather not move a 75lb base either. I think 50lbs is easy. But size matters. A small 50lb weight is easy, but something large with no grips is hard. So its relative. I'm curious what some experiences are with these larger scopes and their bases and how complicated it is to setup and move around. Due to this I have of course considered a SCT because I can get a big aperture there that is more portable, but visually I just am not fond of the narrow FOV and want to at least be able to get a 1 degree FOV out of this scope so that we can look at things at low power and not fuss too much with finding things. I realize some more portable systems use trusses or have collapsible tubes. This seems great, but I don't want to assemble in the field much. Also, opening the tube to the environment (humidity) is not good for me in Florida. I could always shroud it I suppose.
I like to binoview with my Arcturus binos and 1.25" eyepieces. I use 2" eyepieces only for low power wide FOV. I definitely don't want to fool with a scope that cannot easily use binos or a focuser that cannot handle binos.
I'm in Florida. Humidity is 99% from 10pm and on. Every. Night. I don't think an open tube will work here. Maybe I'm wrong? Right now, I have to heat all my optics. All of them. Even eyepieces. Or they dew over in minutes after 10pm no matter what. So this is something to consider as well. I would love to hear some experiences from others in high humidity climates (especially Florida or similar) with respect to this. Maybe I'm off my rocker about needing a solid tube to keep that mirror as covered as possible so it doesn't cool down below dew point.
So, considering maybe something like:
Skywatcher SynScan series GoTo with collapsible tube (use a shroud to seal it up).
$2k to $3500 or more. No time restriction.
Orion SkyQuest series (both solid & truss)
Or, an EQ Platform like one of these and put any big scope on it.
$1250 + shipping on a Crossbow EQ platform. 60 minutes tracking time.
I can put a 12", 14" or 16" standard inexpensive Dob on there ($1k to 2k)
$2500 roughly for the whole thing potentially for a 12".
I'm sort of leaning away from EQ platform and more towards a Skywatcher SynScan as a more convenient option for visual and outreach use.
Where we are coming from, visually:
200mm F6 Quartz reflector on Alt-Az. It handles great. The only drawback is that it's not easy to use after 150x magnification due to no tracking and keeping an object in the FOV. No slow motion control, but I found slow motion useless on a big instrument anyways because you cannot reach it and didn't want long wonky handles poking out to drop, lose, trip on, hang up, etc. So we kept it simple with a TW2 mount and we love it actually. Just not practical for bigger scopes and not good for high power visual with tracking obviously. We want that extra touch. And of course, more light grasp than our 8".
Edited by MalVeauX, 09 October 2019 - 09:54 AM.