Is one scope enough

Hi all,

Currently I have a Takahashi Mewlon 250 on a NJP Mount but being that this is my first medium/large aperture scope I have come to the realisation that scopes of larger aperture are at the mercy of the seeing conditions, which here down under in Melbourne haven't been favorable. How many of you have more than one scope and what would you guys recommend as an in between scope. I am considering a 5" refractor (is that still too big??) to fill the niche...a TEC-140 possibly, I just wish there wasn't a waiting period for these scopes...I hate waiting because I'm at the mercy of the foreign exchange rate which is somewhat in my favor at the moment. I have been keeping an eye out for a TOA-130 but must of the sellers prefer CONUS only buyers. Should I be looking at a different scope and size to fill in between the Mewlon? What have you multiple scope owners got?

I have a 127mm ED refractor
10" Dob
14/5" Dob
Refractor for photography and visual
10" for Planetary
14.5" for DSO

Hello:
I have a few scopes, among them a 12.5" cassegrain, a 12.5" and 8" dobsonian, and a 90mm refractor. Since the cassegrain was built, it's been getting nearly all of the action. It's optics are great, it's on an equatorial mount (a plus versus the dobs), and it has good aperture. It's field of view is only about 1/3 that of the 12.5" dob, but for most objects this isn't a big issue. I've found that the higher magnification and tracking are a big help in hunting down little galaxies. If the seeing is bad, I just keep it to low powers, which pretty much means just one eyepiece since it has a 5m focal length.

I recently had a chance to look through a very nice 5" apo refractor that was, well, perfect (a star test and ronchi test found nothing to be desired). It was clearly as good as a 5" gets, but I liked the image better in the 16" dob next door simply because the images were bigger and brighter. Granted, we didn't try a formal showdown on a planet or high contrast binary, but that's the impression I got after looking at a few nebulae and globulars. In the end, aperture wins.

One thing I'm really not convinced of is how larger telescopes are affected by seeing. Lots of people say that big telescopes are harder hit by seeing. I think it's just more visible with larger telescopes since they a) gather more light, so all of the crap out in the wings of the image are easier to see b) the diffraction disk is smaller, so it's harder to be diffraction limited, and c) larger telescopes tend to be reflectors, with their associated mirror cooling issues. I can almost always see a diffraction limited image with the 90mm, bit I've only seen this once with my 12.5". The reason is that the 90mm only needs 1" seeing to be diffraction limited (quite common) whereas the 12.5" needs 0.3" seeing (quite rare). If bigger telescopes are harder hit by bad seeing, then I should be able to take my 12.5" scope out on a night of bad seeing, stop it down to 4", and see the image improve. I doubt this will happen. Also, if larger scopes are more adversely affected by bad seeing, then how can 8m telescopes get 0.5" images in the optical without AO?

My advice would be to keep the Mewlon of course, but don't worry about getting a refractor unless you really want a wider field of view. Even in nights of bad seeing, you can still go for fainter deep sky targets that will look better than in any 5" refractor. Unfortunately, bad seeing is bad seeing, and there isn't much we can do about it but try another night.

Cheers
Mike Connelley

I think a 90 to 100mm or so APO would be a perfect second scope. It would allow you to get low power, wide field views, and be nice and portable. Add a white solar filter and/or an H-alpha filter and you've got some new abilities.

I often use my 90mm for birding, setting up on the back deck or water's edge somewhere and enjoying some fantastic close-up views of my feathered friends.

Clear skies, Alan

Well, we don't see chaps playing golf with just one club. Therefore we all need at least 9-12 scopes of various sizes, an electric cart and caddy and clubhouse with drinks on tap. "Hand me the 5" APO, will you, George? this is a tricky double...".

The Mewlon 250 is a real beauty. My friend finally got around to collimating his and the resulting views of double stars and Jupiter left us speechless. 5" refractors are really fun- quite an improvement in resolution and what you can see over a 4" (kind of an obvious statement, sorry). The double stars in the 1-2" separation really become fun with a 5".

Ivan

Well, aside from the philosophical issue of how much one actually needs a telescope . I would say that in general 2 or 3 scopes are generally a good idea. Granted at the moment, I only am using an AP130.. Ideally though, I think the optimal mix would be something along the lines of a 3-4" refractor (preferably Apo ) on a mount that can be moved and set up easily for those 30 minute observing sessions. Then I would go with something along the lines of a 6" Refractor or 7"-10" Newtonian/SCT/MCT/MNT. That scope would be for more serious observing and could be easily Equatorially mounted for high power planetary observing. Finally a 12"-20" Dob or 12"-14" SCT for Deep Sky work (well maybe 16" SCT or equatorally mounted larger Newts if you have an observatory .

Just my thoughts .

One of these days when I fill in those niches, I might even decide that I don't need the AP130 anymore.. I might but don't bet on it .

--
Bill

Stellarvue 80mm refractor and a Celestron c-8..........fills most needs for me very comfortably.

Try as I may I have not been able to convince myself that one scope will be enough. Although large aperture is great, it is often, well, cumbersome. Besides, I am now spoiled by refractor views.

Recently, I took a trip to a dark sky site, and took my TV 85 and C 9.25. It was clear to me that one would not be substitute for the other.

If I could only figure out how many is too many.

Rey

TV 60
TV 85
ETX 125
C5
C8
C9.25