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What do you think is the difference between a good and a great refractor?

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#1 Jethro777

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Posted 19 September 2021 - 03:15 AM

I'm guessing if you've had plenty of refractors, there are some that are just a notch above - ones you don't want to part with.  

Why?  Is it because it's spaced in some way you prefer (cemented, air / oil), a lens feature, a particularly interesting focal length, or something else?  


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#2 Sky Muse

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Posted 19 September 2021 - 04:46 AM

I prefer air-spaced, long-focus, and name-brand.


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#3 25585

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Posted 19 September 2021 - 06:49 AM

My 100 Equinox is a very good refractor, my Tak FC100DL is a great, awesome refractor. Having to choose, I would keep the Equinox though.


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#4 Wildetelescope

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Posted 19 September 2021 - 07:42 AM

I'm guessing if you've had plenty of refractors, there are some that are just a notch above - ones you don't want to part with.  

Why?  Is it because it's spaced in some way you prefer (cemented, air / oil), a lens feature, a particularly interesting focal length, or something else?  

Contrast, Contrast, and….Contrast.  A great refractor has a that extra pop in the view.  Darker backgrounds, better definition of subtle features.  A good refractor will show pretty much all of the same things as a great refractor under average seeing conditions, but the image will look more…alive in the great refractor.  That is my take.  Second would be first rate mechanical components.  You can feel the quality in a well made rack and pinion focuser.  The last scope in my arsenal that would go is my 5 inch AP Pre ed glass Starfire.  There is just something extra there in the eyepiece.  Very high contrast views.  

 

Cheers!

 

JMD


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#5 clearwaterdave

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Posted 19 September 2021 - 08:17 AM

I'm guessing about $4000.,


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#6 MalVeauX

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Posted 19 September 2021 - 08:23 AM

I'm guessing if you've had plenty of refractors, there are some that are just a notch above - ones you don't want to part with.  

Why?  Is it because it's spaced in some way you prefer (cemented, air / oil), a lens feature, a particularly interesting focal length, or something else?  

Folk can argue over magical optical figure numbers and their anecdotal ability to see something that others cannot, making refractor-magic just that... magic.

 

To me, at the end of the day though, it's simple: a high contrast, no chromatic aberration view with an excellent buttery smooth heavy duty focuser. Don't care how it looks or what name is on the side of it.

 

Very best,


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#7 Traveler

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Posted 19 September 2021 - 08:31 AM

One thing a great refractor will have, is just snap the view in focus without any adjustments afterwards...



#8 donadani

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Posted 19 September 2021 - 08:33 AM

good = used sometimes

great = used always

 

:)


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#9 lu270bro

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Posted 19 September 2021 - 08:38 AM

For me its my AP Traveler.  Just as portable as my Stowaway, but a 4" with superb color correction and built / machined / manufactured like a tank.  The wide field views with a 26 or 31 nagler are just awesome.  Its a fast scope, and I enjoy the wide fields.  I own a  new Stowaway and a 130GT from AP as well, and would sell those and keep the Traveler every day of the week and twice on Sundays without question.  My Traveler will be the last scope I part with.  Its just a magical scope, to me at least.


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#10 Jon Isaacs

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Posted 19 September 2021 - 09:30 AM

The difference:

 

A good refractor:   You own it.

 

A great refractor:    I own it.    :lol:

 

Kidding aside.. A great refractor is one that is well suited for my observing style, suits my needs. 

 

In my world, the NP-101 is a great refractor.. it's not too heavy, it's 540 mm focal length combined with the modified Petzval design means a flat-flat 4.88° field is possible while it is still very capable at high magnifications.. 

 

Jon


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#11 Voyager 3

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Posted 19 September 2021 - 10:22 AM

I'm guessing about $4000.,

And small .

#12 Rollo

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Posted 19 September 2021 - 11:11 AM

Something in the 5in. range and f/8 or slower is my preference.   Lightweight and easy to setup, but enough aperture to do nice deep space and also give good views of planets and moon.   Nice all around grab and go.  


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#13 Echolight

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Posted 19 September 2021 - 11:29 AM

An ST120 with ED glass (FPL-53 air spaced doublet), a 2.5 inch rack and pinion focuser, and add on field flattener, with a sliding dew shield, in a  low weight package would be a great refractor to me.


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#14 mikeDnight

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Posted 19 September 2021 - 12:28 PM

The difference between a "good" refractor and a "great refractor" will likely only be noticeable on the very best of nights, with the weaker of the two showing a softening of the star image at around 300X. The greater one will just keep going at 500X as if it wasn't even being tested.


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#15 areyoukiddingme

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Posted 19 September 2021 - 01:28 PM

That's what I've noticed with my Stowaway comparing with my Orion 80mm F6. 

 

The Orion is really nice little scope, and on the best nights it does very well indeed. But I do find myself cranking power on the Stowaway, and not realizing until after the fact how I've gone a lot further than I otherwise would have expected to.

 

Same principle applies with reflectors. Similar effect with an 8" F7 reflector. I'm having struggles with the cell for my 12.5", playing around on Jupiter last night I was finding about 200x is as good as I could get, and attributed it to the seeing.

 

Then I swap to the 8" and I'm doing 330x on Jupiter two minutes after setting up (shaddow transit plus GRS last night was nice!).


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#16 nva

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Posted 19 September 2021 - 02:20 PM

The right glass figured well for it's design with a good focuser in a well constructed tube?

I'm not being oblique here there are lots of ways to make a telescope, a great one is made well for it's purpose.

Edited by nva, 19 September 2021 - 03:02 PM.

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#17 Scott Beith

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Posted 19 September 2021 - 05:19 PM

Functional - 1/4 wave optics with a descent mechanical build

good - 1/6 wave with a more refined mechanical function

great - 1/10 wave with an outstanding mechanical build.



#18 Nippon

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Posted 19 September 2021 - 05:27 PM

Excellent optics combined with simple and reliable mechanicals. That has turned out to be a Vixen ED 103s for me.


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#19 John Huntley

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Posted 19 September 2021 - 05:28 PM

Good - always pleases, often surpasses expectations.

 

Great - always surpasses expectations.


Edited by John Huntley, 19 September 2021 - 05:29 PM.

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#20 gwlee

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Posted 19 September 2021 - 05:56 PM

$$$$$


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#21 Lagrange

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Posted 19 September 2021 - 07:04 PM

I'd say I agree with Jon in terms of the practical definition of a great refractor.

 

If you have a refractor that makes you want to get out and observe at every opportunity because you enjoy the views so much and it's a pleasure to use then it's a great scope for you whether it cost $100 or $100,000.

 

Defining it from a less personal perspective I'd say it's a combination of superb optics, high quality and durable build, and mechanicals that are a reliable and precise.


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#22 Lagrange

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Posted 19 September 2021 - 07:07 PM

The difference between a "good" refractor and a "great refractor" will likely only be noticeable on the very best of nights, with the weaker of the two showing a softening of the star image at around 300X. The greater one will just keep going at 500X as if it wasn't even being tested.

That's so true. I've just been observing Jupiter and Saturn at 119x with my FC-76Q and while there were glimpses of great views and it was obvious the scope could take a lot more magnification, the seeing just wasn't good enough to really let it shine.

 

Still enjoyed the views though!


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#23 Chilihead

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Posted 19 September 2021 - 07:57 PM

My next door neighbor invited me over for his wife's birthday yesterday. I have my 8" Edge on wheels, but I carried over my AT102ED on a Twilight I instead. 

 

The moon, Jupiter and Saturn wowed the crowd.

 

The Edge is a good scope. The AT102ED is a great scope. It gets used 10 times more than the Edge.


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#24 DeanD

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Posted 20 September 2021 - 02:07 AM

My 100 Equinox is a very good refractor, my Tak FC100DL is a great, awesome refractor. Having to choose, I would keep the Equinox though.

I am intrigued. Why would you keep the Equinox instead of the "awesome" Tak?



#25 Bowlerhat

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Posted 20 September 2021 - 02:44 AM

The one that you can always count on without worrying a thing, and it works on it's own. No need to buy tons of paraphernalias just to make it barely work.


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