For achromatic refractors, I think 4" is that sweet spot, light enough to be portable, big enough to do serious work, and not heavy enough to require a crazy mount. At anywhere from F/10-F/12, they're pretty manageable. Also they look good! My 4" F/10 is my go-to outreach scope.

For Dob's and reflectors, my big breaking point is having to use a step stool - I don't like getting on ladders and the like for observing, so given my height that probably puts my upper limit on a Dob at around 12.5, maybe 14". I do like the idea of a fast f/ratio 6"/8"/10" reflector, guess I'm going to find out soon how they work in practice, though to be fair they basically become CAT's once you slap on the coma corrector.

If I ever end up getting a car or an observatory, I definitely like SCT's in their bigger sizes, they don't give up much to big, fast Dobs (IMO), and the couple times I've helped set them up, they seem easier to set up. The 8" SCT is just about the perfect all-around scope. Of course, I really, really love Mak's - I'd love to get a 7" Mak at some point in time, cooling issues be damned. My first go-to scope was a 5" Mak, and I'm very fond of it - optically fantastic, and pretty good as an all-around scope. Its my default scope, and will continue to be until the mount eventually goes kaput.

Broadly speaking, given my current situation, 8" is about all the aperture I can realistically handle (no car, living in NYC, need to hike up 4 flights of stairs to get access to my roof), and that would be in an ultra-portable dob format. I've been saving up for a while for one of those, so here's hoping!

 

Interesting question. After observing for over 50 years, I feel blessed for having the opportunity to view obscure DSO's, beautiful nebulae, planetary details, resolving globular clusters and splitting close binary stars thru my APO's, SCTs. huge Dobs and binoculars., most of which I sold upon my self-imposed exile to the Philippines. But I could not part with my Short-Tube 80, mounted on a simple ball-mount tripod in alt/az mode. It comes with me everywhere I go (total weight is less than 6lbs) and the views and versatility still blow me away.

 

In my case, it has come down to an 80mm Stellarvue f/6 AT1010 refractor and a Meade LX200 8" SCT.

The refractor is lightweight making it great for quick views and viewing wide swaths of the sky. At home, I use it with a good alt-az mount. On travel, I can still use this scope with a photo tripod, and I keep an erecting diagonal in my travel bag so it can double as a terrestrial scope too.

My SCT is generally parked in my backyard, but it is still portable enough where I can bring it to the front of my house (I have to carry it in smaller sections through the house) when there is something interesting low on the western horizon which is blocked from my backyard. It has enough light grasp to show details and support higher magnifications, and while I am perfectly adept at old-school star-hopping, the go-to helps a lot in my light polluted skies.

In fact, my most commonly used setup is this SCT with the above 80mm AT1010 sitting as a large finder on it.

Harry D.

 

I love observing DSOs and prefer an alt-az to an EQ mount so my ideal scope would be a Dobsonian with an aperture of 12 inches or more. My back says otherwise. That's why I have an 8-inch Newtonian OTA with a mount that breaks down into smaller, lighter components.

 

I'm with Dr. Ski when it comes to my preference for smaller, lighter, portable scopes. This is because of my advancing age, inability to carry heavy stuff, and living circumstances.
The scope that now sees the most use is a vintage 60mm f/13 refractor on a Unitron model 114 alt-az mount.

 

I do not have much free time for watching . I'm living in city sized metropolis. The temperature changes between -2 and 38 degrees Celsius (-28 to 100 F), relative humidity 10-90%, visual magnitude limit between 3 and 5.5 depending on the humidity, direction of air currents, clouds and even dust from inside the country. Buildings retains a lot of heat during the day (23 degrees latitude). Hot nights there is little difference temperature, cooler nights there is low altitude atmospheric turbulence. The subtropical jet stream helps in some months clearing upper atmosphere of clouds, at other months otherwise.

My setup was adjusted to make the most of every night can offer.

Setup refractor 90mm F/10 plus Explore Scientific wide field eyepices: is using to watching wide field like brightest nebulae and open star groups at nights with visual magnitude limit until 3.5 or much atmospheric turbulence.

Setup Maksutov Cassegrain 90mm F/13 plus volcano top eyepieces (Vixen Kellner and Circle T-Abbes): same conditions for observing Solar system, closed stellar groups and to split stars.

Setup refractor 150mm F/8 plus Hyperion eyepieces: is used at nights with visual limiting magnitude between 3.5 and 4.5, when there is significant atmospheric turbulence. The quality of Hyperionons does not make much difference considering the atmospheric conditions. Little is lost when comparing with Panoptics or LVWs these nights.

Setup Schmidt Cassegrain 230mm F10 plus 16 Japanese flat top eyepices(Ultrascopic, BGOS and similar): is used at nights with visual limit magnitude beyond 4.5. The transparency of the night is good, there is no need of large magnification. The eyepiece is chosen according to the true field or limited according low atmospheric turbulence.

Open tubes were excluded for less impact of variations of temperatura during the night.

Focal ratio arround 10 was chosen considering my preference for narrow field of classic eyepieces.

 

I use a 102mm for planetary and a 85mm for everything else. If I'm not using this setup then I use a 85mm for planetary and a 102mm for everything else. The others are just collecting dust.

 

For me, the optimum compromise between having enough aperture to see faint DSOs and having a scope too big to move and handle easily is the 12.5" dob. It can see a literal lifetime number of objects, and it has better resolution of lunar and planetary details than any refractor I've ever looked through.
That being said, wide field is a good reason to have a shorter focal length scope, so I also own a 4" triplet refractor, which performs excellently and gives a maximum FOV almost 3x as wide as the 12.5".
I value both types of instruments and wouldn't want to be without either.

You don't NEED to have 12.5" of aperture to be happy observing. I observed for 30 years before I ever had a scope larger than 6". And an 8" aperture could easily be a lifetime scope if one observed under superlatively dark skies. But I find the law of diminishing returns cuts in sharply right above the 12.5-15" size, and that scopes smaller than 4" really have too little light grasp to display anything very well unless the scope is a binocular telescope. I've been fortunate enough to view through instruments of 2" through 60" over the years. Each of us has his own reactions to different sizes, but my biggest enjoyment of viewing has always been in 4" to 12.5" scopes.

 

I don't know that I have enough time in the hobby to answer but I am going to listen in to see what others have to say.

 

To me, this is a question I can't answer. It's in the same league as asking me my favorite color: I don't have one. This as let's say 'blue' was one's favorite color. So how would the world (or universe) look if everything you could see was 'blue'? You wouldn't have that favorite color for very long, now would you?

Everything is counterpoised as an offset to everything else. It is only by this form of offset that we even can know of the difference. This then goes to the heart of philosophy. Everything dances with everything else to announce it's beauty through the very difference we, as human-beings, are capable of perceiving.

This is why I rather chuckle when someone announces that their favorite color (telescope) is 'x.' It wouldn't stand up to cross-examination for very long. On a more practical note, I decided I wish to pay a bit more attention to our own local neighborhood: Planets. Moons. Comets. Etc. I already have a very capable refractor (two) for such. But there is one flavor of telescope I haven't explored much that just so happens to be said to excel at such critters: A Maksutov-Cassegrain.

So a 150mm Skywatcher Mak is currently hurtling (bouncing) it's way to me from across the country. But it's not my favorite.

I'll go away now..... Thank you, Bill, for starting this thread.

 

#1 is the good old Achromatic Refractor, 4" aperture, f/15 & f/5 for city & country. My Edmund 4" f/15 is my favorite scope ever - and I've owned & used quite a few over the past four decades. My Jaegers 4" RFT doesn't get enough starlight, but in 18 months (retirement) that'll change.

#2 is the 6" f/8 Reflector. Gotta get me one of these before I depart this world. Every one I've used was a great observing experience.

 

That sounds great, Bob! I had the 3" F/15 model from Edscorp back then. The EQ-mount was atrocious, but the scope was wonderful. Aside from the focuser - which I would have replaced if there were good one's available back then like today.

Alas - mine is now gone,

Dave

 

Man! Hate that you no longer have your Edmund 3" refractor - I'd make you an offer you could refuse! The oldest models of both apertures have lenses made by Carton (Japan), and are every bit as good as Unitron's N-S optics. The mount for my 1950s E4 is among the best - once balanced - it glides along with near zero resistance and no backlash. I can manually track at 400x by leaning against the focuser housing with no vibrations.

 

I've only had about half a dozen scopes so far, starting off with the 6" f/8 Criterion RV-6 and quickly moving up to the 8" f/6 Meade 826 back in the day - 35 years ago. After a 20 year layoff, I first got an awful 4 1/2 inch reflector, followed a few years later by an even more awful - absolutely awful - 5 inch Bird-Jones reflector, the Meade DS-2130 in my signature, which I've denigrated sufficiently in another thread.

However, in my latest return into astronomy, almost two years on now, I bought the two other scopes in my signature. the Celestron NexStar 127SLT 5-inch Mak, and the Orion ST-80 3.1-inch refractor. I love both scopes, but I do want something bigger on both fronts. Like Diogenes, I aspire to one of those 180mm Maks - I have my eyes on the Skywatcher version - and I'm also interested in a honking big 6" refractor - I've been drooling over Explore Scientific's AR152 for quite some time now.

What I can say, however, is that the combo of the Mak and 'frac I have now together give me the practically perfect scope. The Mak excels at high magnifications, but is beset by a relatively narrow field of view and long cool-down times. On the other hand, the ST-80 has neither of those problems, and gives me glorious wide-field views at low magnifications. And both scopes are very portable, easy to take out and just start observing. The goto is terrific. What more could anyone want?

 

Your favorite aperture and design?
The one's I've finished....

 

Love refractors for their crisp views, visual ease of use. Though I've owned some triplet lens up to 160mm and several small ones in the 85/90, I just bought one of the new Tak 4" (the 100DF). I'm very impressed by many (in ways all) of the doublet refractors I've had a chance to view though or with that use any of the modern glass combinations and or Fluorite. I have changed every scope I think except my FS-128 which is think my favorite all arounder? I sold my FS-102 to move up to the 128, which is why i now again own a 4" Fluorite doublet.

I was bit by the refractor bug maybe 2006, up to that time I was a Cat man. I'd loved my Meade's over the years but started having support issues, so switched to a Celestron C11 and really enjoyed it! Around the time I bought the C11 I also bought my first heavy duty EQ mount (the CGE). My hope was that the EQ mount would not be as difficult near zenith as the forked alt/az. I think both have their issues. I still often recommend an 8" Cat with goto and tracking to anyone that asks and new to the hobby.

I waited to buy a large Dob until Orion came out with their XXg's as I wanted inexpensive goto and tracking, and easy warranty support. Now I love my XX14 on anything that will fit the view. It does not replace the refractors, but adds some much needed aperture horsepower where it can help, and that is almost everywhere. I often cannot use it in the higher/highest mag's but it still makes a big difference anywhere light gathering matters. I suppose here I am comparing planetary to maybe globulars... Viewing at zenith not an issue!

Though I no longer own any Cat scopes, I feel each type design and implementation has it's strengths and tradeoff's.

I now like to view objects with both the 14" Dobster and the 4" or 5" refractor same night. I feel very spoiled by this and never forget to thank my lucky stars. Comparing the views is really enjoyable to me, I don't feel either is better, each offers it's own rewards or advantages whether it be the 'hanging in space effect', ease of use, or field of view for the seeing.

Can't seem to figure out how to upload/ attach a file to this post from my computer, but I was going to post an image of the 14" and the 5" pointed at Saturn a few weeks ago...

 

Thank you for the help!

 

So you say that Meade had/has 'support' issues? I believe I know the epoch of which you speak.

I'd attempt to get a straight answer from their so-called "Customer-Service" people (?), and they'd laugh at me. I'd demand to speak to the 'supervisor' and get a stern voice who'd tell me to junk the (12" LX200 GPS) scope and buy a new one. If I said it was a quite new instrument, I'd be told they would take it back from me. I'd say "Will you repair it?" - and be told "No. We have tons of newish scopes out back. We send 'em ALL to the junk-collectors!" -CLICK!-

I was amazed by these morons Meade Instruments had assembled in one place! I'd only hope they'd padded the walls and made sure the door could be securely bolted-shut from the outside. This was where I learned first-hand the importance of buying from a very good dealer/shop who'd deal with these pinheads for you. I also praised Pete Peterson and his kits, and even wrote some copy for him to market these. How'd you like the right-side clutch on the forked AZ-mounts that came with their LX-series Cats? Among other fascinating 'oversights' by Meade's designers. Optically, the Cats were truly fantastic instruments. Still are. But the human-interface for these was horrific - and still are. After about 30 years in which to fix these deficits which would cost them hardly anything to do and enact.

Fortuitously I was previously trained as a high-end mechanic for bicycles, and had/have a house full of fine tools, and the skills to use them. Adapting this to optical instruments was quite easy. And Pete's kits were a breeze anyways. For other 'bugs' I'd figure out what to do intuitively and make it happen - and publish my recipe in the myriad astro-forums then in full-swing, out of necessity, I'm sure.

I too have a love of refractors. Of the one's I've owned over the decade, all have been achromats (two lens-elements). My first purchased scope was a Edscorp 3" F/15 refractor. By todays' standards, it would be laughed at for it's crude focuser, pathetic way of mounting, and other things. The equatorial-mount it came with was the grand-prize-winner for wost thing ever constructed! But I loved it all the same. The views it gave me were priceless. It's abilty to split close double-stars was spot-on at the limit for a 3-inch lens. And no one ever talked about chromatic-abberation (blue/purple-fringing), or CA, yet. As CA goes, it never has bothered me to this day. And I love my diminutive ST80 F/5 achro. As well as my 127mm F/9.3 Meade AR5, which is also an achromatic-refractor. Mounted on an LXD55 equatorial GoTo-mount. Seems that back-in-the-day (2003) that everyone who bought these chose the 150mm (6-inch) F/8 of the two - AR5 and AR6 - except me. Always one to throw trends in the trashcan of society, a 5-inch was what fit the bill. It deliver beautiful views brimming with high-definition contrast.

I see you've learned to upload images. So my services may rest - for now.....

Great post, Klaatu - now I'm off to play among the stars!

Follow that Saucer -

Dave