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Visual observing: big APO refractor VS. big Dobson

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263 replies to this topic

#251 N-1

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Posted 10 January 2021 - 01:42 AM

I use a telescope to better see what objects would look like if I was closer to them, as if I was looking at them with my eyes. The intensifier does not interest me.


What an elegant way to describe what visual is all about. Well said!

#252 Bomber Bob

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Posted 10 January 2021 - 10:48 AM

Back On Topic:   It's been mentioned already in the thread, the Convenience Factor.  My work night sessions are short, and I'm more likely to take out a small scope vs. a Big Scope.  My mitigation is to make deploying a Big Scope easier:  Mounts stored in the shed.  Casters on the heaviest EQs.  Multi-scope / common mounts with rings & dovetails for quick & easy swaps.  It can be done.  My only limitation for now is cradle height.  But I have everything settled to where using my 8" Newt is no harder than my 4" refractors.  Scope selection is back to Object Type and Seeing, as it should be...


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#253 Garyth64

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Posted 13 January 2021 - 09:42 AM

5 pages of intensifiers . . .

 

Back on topic.

 

I had a 10" f/7, that gave very good views of DSOs and planets.  But on a rolling EQ mount I was limited on where I could set it up easily.  The OTA was getting to heavy to carry

I have a 5" refractor that gives very good views of the planets.  Not so much on DSOs because of it's aperture.  It was easy to set up and went with me to a lot of outreach events.

My 6" f/10 newt is great on the planets, but on it's heavy mount, it is restricted to where I set it up.

I purchased an AT130EDT two years ago, and it was excellent on the planets.  It went to a lot of outreach events, but it just didn't bring in the DSOs.  I sold it off.

I have an 8" f/4.5 that did very good on DSOs, but I wanted more.

Sometimes a telescope finds you, and I came across a 12" Hardin.  Aha, that is what I needed for some DSOs.

 

So, for the original question of the op,

 

"let’s say 130-140mm, APO refractor compared to a good 12-16” Dobson?"

 

you shouldn't really compare a 130 apo to a large newt.  The large newt (or dob) will show fainter objects, and if it has a good mirror, more details on the planets.  I think it's also up to the observer and the satisfaction he can get from either.

 

(Sorry for the long post. For me, when a post gets too long, or even looks too long, I just pass it up.)


Edited by Garyth64, 13 January 2021 - 09:48 AM.

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#254 rgsalinger

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Posted 14 January 2021 - 12:04 AM

Any further discussion of intensifiers rather than the topic here will be removed. Please just get back on track. 

Rgrds-Ross


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#255 Nate1701

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Posted 14 January 2021 - 01:09 AM

These discussions are always so humorous with it running the range from a scope is better if it can see dimmer things (mirrors) to what makes it best of versatility from wide fields to planetary (refractors).  In truth, as far as I'm concerned is that none of that makes a good instrument or a best instrument.  Indeed, what really make an instrument best is the one that you find you take out the most, is most intuitive for you, is not a hassle to get ready but more like a friend in the field.  So basically, it is the scope that you personally like to be with more than any other scope.  That can be a 60mm achromat or a 30" fast Dob.  So for the person who enjoys the night sky with a little 60mm, then that aperture is better in every way than the 30" cow.  Conversely, if for the person who enjoys the night sky with a mammoth 30" cannon, then that aperture is better in every way than a 60mm pea shooter.  So aperture means nothing, the observer's personal likes means everything.

 

ps - Nothing better than my 4" Apo grin.gif  Nothing!

My favourite comment in this thread, and probably one of the best on this entire forum IMHO. Thanks Bill!

 

Sometimes these hypothetical questions "Big This vs. Big That" seem pointless - but the wealth of insight that gets generated from and shared is very valuable to budding amateurs ready to take their game to the next level. And for the less experienced; often it's a question of "What do i buy next?"  or "Will it really satisfy me if...?" doing some research and reading in threads like these can really educate.

 

After a Nexstar 8SE i have no desire to go really big, It took enough time to setup and tinker with. I would rather own small and quality and use it more often. So comments like above really inspire me. And mostly reassure me that i don't need a GIANT scope and a ladder to be satisfied in this hobby.

 

There were some strong opinions on this thread. And for me it's not tiresome bickering, it's Strong opinions coming from experience. And experience is very valuable to those who are still learning. 

 

The OP indicated interest in AP in his future - so the suggestion of Electronically Assisted or NV was valid.

 

Personally, i appreciate tom_fowler's and bobhen's point of being able to see more with less ( aperture). And for me - this is where i am at in my journey.

My 5 inch Mak becomes a much larger scope when i take a 30 second exposure with a DSLR. I'm just beginning to learn DSO photography and just got a 80mm triplet used. Someday i might get a better mount. But so far My Exos-2 mount with a single drive is good enough to track for 30 seconds at f12 - that's good enough for me at the moment. It's enough to get me more out of my small scopes. And for me this is the sweet spot - small portable scopes that i can enjoy visually - and if i want more - i dont have to drag out a big rig - i just setup tracking and attach my camera. I will probably never afford a night vision eyepiece. But a DSLR is the answer for me.

 

The Grand Canyon analogy was interesting. People don't want someone else's pictures - they want to visit and get their own. Otherwise why bother travelling at all?

Jon's comment about Sitting out and enjoying all the shadows and sunrise/ sunsets many times through the year? Well that's great if you live down the road. (And don't get me wrong I respect Jon's experience, and love his posts) But the majority of us don't live down the road from the GC. Many tourists do spend more time documenting their trip, rather than experiencing it - i totally get that. But if i told you that i was to travel to the Grand Canyon because i wanted a picture for my office that I took instead of buying someone else's , and i spent the time studying and setting up and waiting to get the perfect shot. Did i miss the experience or did i immerse myself in it? I would say it's the latter. I Absorbed a lot visually along the way - and i have an office picture that really means something to me. It takes me back on the entire trip every time i look at it. My point is: I don't think that "imaging is not observing" can be dogmatically stated.

 

I'm not retired and i Dont have a backyard. I also don't live near a desert. Clear skies and fantastic seeing don't happen as often when situated in the humidity bowl of the Great Lakes. I want a souvenir from my nights - that's what i have learned. I've sat for hours in 0F (-18C) staring at a the eyepiece as my eyes get better at gathering more information. Now - i'd rather have a picture to show for all that observing time. I keep log books, and pasting a picture in my notes gives me a lot of delight, even more than my sketches.

 

I used to think that taking a picture or using digital was somehow cheating myself of the natural experience. But now i've come to realize that there is no such thing, no more than using a scope is cheating over the natural experience of using your eyes. It's just instruments that enhance your vision. And please don't get me wrong - i appreciate visual only and the whole experience of photons travelling down your retina with out a digital modification in the way. But anything that takes a sweet little MAK or refractor and will enhance it; rivalling views of much larger aperture - that is the investment for me.


Edited by Nate1701, 14 January 2021 - 01:44 AM.

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#256 Jon Isaacs

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Posted 14 January 2021 - 08:00 AM

And mostly reassure me that i don't need a GIANT scope and a ladder to be satisfied in this hobby

 

 

 

Just to be clear, all my scopes provide a satisfying experience. If they didn't, I wouldn't have them.  If you look at my signature, you will see i have a number of scopes.  Each is satisfying in it's own way.  

 

Carton 60mm F15 1.jpg
 
(60mm F/15)
 
It's nice to have a variety of capabilities.  What is satisfying is just looking through a telescope, 
 
Jon

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#257 Nate1701

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Posted 14 January 2021 - 10:37 AM

 

Just to be clear, all my scopes provide a satisfying experience. If they didn't, I wouldn't have them.  If you look at my signature, you will see i have a number of scopes.  Each is satisfying in it's own way.  

 

 
 
(60mm F/15)
 
It's nice to have a variety of capabilities.  What is satisfying is just looking through a telescope, 
 
Jon

 

And that is precisely why i value your comments Jon - because you see the value in all kinds of instruments from naked eye to Binos to Refracs to Reflectors. And you have an appreciation for each tools unique ability to help savour the moment. It's not just the knowledge, but the knowledge + appreciation = pure astro gold for others who are trying to figure out what is best for them.

 

It's comments like yours, Greg N, Bill P and others that can save a lot of time and money - and frustration. It's when you guys say "I had a great night with this small scope" that guys like me think "hey, he's right - if i don't have the space or time for a Giant rig i don't need to wonder if I'm missing out - just take my small scope and get out there and enjoy it! That's what these guys with 30, 40 or 50 years of experience are doing."

 

Don't worry - i never took anything you said as "a Giant Dob is the only way to go".

 

The statement you quoted is from a lot of comments here that really made the point that a 12 to 16 inch mirror is for sure going to beat an 6 inch APO. There is a "don't kid yourself" factor to all this, can't argue with physics and experience proves it etc. etc. etc.

 

However a lot of of other interesting alternatives, benefits, viewpoints got mentioned. This thread is a goldmine IMO. There are merits to a large APO, but can't afford it? There are merits to a Giant Dob - but don't have the time or space?  That is where a lot of amazing comments and suggestions come out - because many can't afford it or don't have the space. But most can afford a 6 or 8 inch Dob - this is the middle ground - not extremely expensive or extremely big - and the fact that these alternatives and the merits of them get mentioned so often is VERY comforting to those who don't have money for the very expensive, or the space for the very big.

 

p.s. But i did think your "imaging is not observing" is a bit dogmatic. sorry. wink.gifflowerred.gif What if i observe my images? Which i do. I cherish them. to me it's just another tool that enhances the experience. 


Edited by Nate1701, 14 January 2021 - 10:48 AM.


#258 Astrojensen

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Posted 14 January 2021 - 11:16 AM

 

And mostly reassure me that i don't need a GIANT scope and a ladder to be satisfied in this hobby.

The moment you develop a bad back, as I did last summer, you'll instantly cherish your small scope. Suddenly,  when it's simply the only possible way for you to get to see some starlight, you'll start see it in a whole new light. 

 

 

Clear skies!

Thomas, Denmark


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#259 noisejammer

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Posted 14 January 2021 - 02:32 PM

Ok Gu's, that's enough.

 

I am sure that II's are entirely wonderful and you can even see glimmerings of the Big Bang, if only you squint in just the right way. Nevertheless, this is the REFRACTORS forum and the topic is big apo's vs big Dobs.

 

If you really want to discuss the merits of intensifiers, their price, their phosphor, their availability in Canada or even something tangentially related, please do it in the Night Vision Forum.

 

Next - when you quote someone's post, please be polite enough to edit it down to the part you're referring to. Forty line quotations are a bit tedious.

 

Finally - I've removed 46 posts from this thread. My apologies to those whose on-topic posts were nailed in the crossfire.

 

Clearest

b


Edited by noisejammer, 14 January 2021 - 06:08 PM.
fixing a brain fart

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#260 Nate1701

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Posted 14 January 2021 - 02:42 PM

Well I'm saving up for a 4 inch APO - that's what i got out of this thread.


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#261 Bomber Bob

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Posted 14 January 2021 - 06:37 PM

Well I'm saving up for a 4 inch APO - that's what i got out of this thread.

Great -- get that Workhorse Scope.  Add an 8" or 10" reflector, and you'll be set.  I like all my scopes (based on my Signature, I like scopes a lot!), but my 4" frac & 8" Newt get the most use now.  If I cut my collection to just these 2... I'd have to decide which 4" frac to keep -- not an easy choice.


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#262 John Fitzgerald

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Posted 14 January 2021 - 08:08 PM

I like to keep a 6 inch refractor and a 12 inch reflector.  According to a lot of old literature, they are equivalent.cool.gif lol.gif


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#263 JMW

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Posted 15 January 2021 - 08:49 PM

In non-COVID years I can get my big dob fix with our club's 20 or 24 inch large dob at monthly star parties. I also go to the GSSP every year and OSP some years. Plenty of even bigger than 24 inch scopes there.

 

My largest Dob is 14.5 inches and my 8 inch Dob gets more use because it takes up less space and is much faster to setup. I am very satisfied with our TEC 140 and decided that a larger refractor isn't financially or logistically viable for the type of astronomy camping we do. 

 

I always feel that a modest size scope under ideal dark skies can out perform a huge scope in an urban environment. I enjoy my SVR90T under dark skies more than my 14.5 inch Zambuto dob at home.

 

I think a quality refractor and a quality manageable Dob is a great combination. It doesn't need to be one or the other.

 

I do have a 10 inch f/4 newtonian mounted on an AP900 in my observatory at home. It is great for EAA but I hardly use it for visual even though I have the rotating rings. EAA is a good way to overcome urban light pollution. 

 

Threads like these are great fun and a way to waste time when clouds prevent observing. 


Edited by JMW, 15 January 2021 - 08:50 PM.

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#264 Jon Isaacs

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Posted 16 January 2021 - 04:12 AM

I always feel that a modest size scope under ideal dark skies can out perform a huge scope in an urban environment. I enjoy my SVR90T under dark skies more than my 14.5 inch Zambuto dob at home.

 

 

My viewing is split up into a good portion of the month under dark skies, enough that I get my fill of DSOs, and then the rest of the month is under light polluted skies but with better seeing, it's double star/planetary time.

 

So, I enjoy both but in different ways.  And I enjoy both small scopes and larger scopes but tend towards larger scopes because I do see more whether it's DSOs or the planets/double stars.  

 

Jon




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