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Refractor vs SCT

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#1 Itz marcus

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Posted 22 September 2014 - 11:08 PM

Hi,

I am about to commit blasphemy (although not on this forum). I have had and EON 120 for about seven years and I have used it and used it and used it!!!!!! I love that scope and it sure treated me to amazing sights and many wows. However, since I got my C8 I have really not taken out my refractor more than a handful of times. I find that I prefer the views in the C8 to the refractor :banned:. I like the views of the planets and deep space more. Sure the stars are not as tight and the diffraction ring a tad brighter but the detail on everything is much easier to see. For example m13 is absolutely jaw dropping in the c8. It's nice in the refractor as well but not comparable to the C8. Same with the m57, the double cluster, m42 etc... In wide field views, of course, the refractor wins hands down.  And yes my sample of the EON is a great one. I had it tested by O.M.I. and it tested at a strehl of .96. I was told that the C8 would be about the equal of the refractor even though the C8 is much bigger but my experience (maybe it doesn't count for much because I am a low level amateur) has not been that way. I sure an 8 inch refractor would blow away the c8 but hey you can't easily get an 8 inch refractor unless you're plunking down serious $$.

Just my 2 cents

Clear Skies

Itz

 



#2 Brian Carter

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Posted 23 September 2014 - 12:10 AM

Yup, aperture wins :)

#3 WesC

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Posted 23 September 2014 - 12:29 AM

M13 in my Edge11 is just mind blowing compared to my 105mm APO. It's just aperture and image scale. I'm happy I have both scopes. :)

#4 korborh

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Posted 23 September 2014 - 01:06 AM

SCT 1, Refractor 0



#5 MB_PL

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Posted 23 September 2014 - 02:28 AM

Some time ago I had a Skywatcher 120 ED and a C8S simultaneously for several months. I too ended up selling the 120 ED. The difference in resolution on the Moon was visible at first glance. The C8S showed a tad bit more low contrast detail on Jupiter and Mars. When the seeing was good, the difference in high contrast detail on planets was clearly visible. I used both scopes over 90% of the time for lunar and planetary observations with a binoviewer, as I have a big Newt for DSOs.

I have never regretted selling the ED refractor and keeping my C8S.

But on the other hand I have considered the idea of moving to a 6" APO. What I would lose on high contrast lunar/planetary detail, I would regain among others on low contrast detail (a C8S performs pretty much like a 127 mm unobstructed scope on low contrast detail) and less vulnerability to my slowly deteriorating local seeing conditions.

I guess what I'm trying to say is that comparing a 6" refractor to an 8" obstructed scope would be more of a fair contest.

Clear skies



#6 Sarkikos

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Posted 23 September 2014 - 06:27 AM

And I was thinking about getting a 120ED!  One advantage I could see to the 120ED would be quicker cool-down time, especially in the cold months.  Maybe a 120ED would not be so bad for a winter planet/lunar scope?

 

Mike



#7 Eric63

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Posted 23 September 2014 - 07:19 AM

And I was thinking about getting a 120ED!  One advantage I could see to the 120ED would be quicker cool-down time, especially in the cold months.  Maybe a 120ED would not be so bad for a winter planet/lunar scope?

 

Mike

 

I think that a 120Ed will stil need at least 30 minutes of cooling duing cold months.   After a few winters of observing up here in the Great White North, I realize that once the temp drops below 10 degrees Fahrenheit I only go out for short sessions.  That's why I got the ED80, I figure that it should cool very fast ( I will let you know next spring anyway  :grin: ).  My Mak can take well over an hour in winter so I only use it if I can plan ahead; but in the summer it's ready to go as soon as it comes out of the air conditioned house.



#8 Sarkikos

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Posted 23 September 2014 - 07:28 AM

My 150mm Mak takes longer to cool than my EdgeHD 8".  I guess the two vent holes help the 8".  But in general the Mak takes a good two hours.  It's been awhile since I've taken the Mak out.  If I were more confident about shipping OTAs it would be sold by now.

 

Yes, let us know about the 120ED. (Maybe the Refractor Forum would be more appropriate.)  So far I'm happy with my C80ED.  Very little cool-down time required and a sharp, contrasty image.  It makes a good showing of fine lunar rille systems.

 

Mike


Edited by Sarkikos, 23 September 2014 - 07:29 AM.


#9 joe4702

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Posted 23 September 2014 - 08:14 AM

Since getting an Edge 8, I only use my 100ED for lunar and white light solar viewing.

And only then due to ease of cary and setup, not superior views.

Although, if I put the SCT on my M2 mount instead, it would be almost as easy, just a tad heavier.

A fast wide-field refractor probably makes more sense paired with an SCT (the 100ED is f9).



#10 rmollise

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Posted 23 September 2014 - 08:42 AM

Right tool for the right job. The SCT has the edge with light gathering power, which is usually your numero uno requirement. However, a smaller APO can produce incredible views. You may not go as deep as with a C8, but the trip will be well worth it. And an 80 - 100mm APO can produce the tack-sharp wide-field images an SCT just can't deliver.

 

I'm sorry, y'all; I gotta be honest...the older I get, the more I appreciate my small refractors. Not that I will ever stop using a C8. ;)

 

The solution? "Both." :lol:


Edited by rmollise, 23 September 2014 - 08:43 AM.


#11 Daniel Mounsey

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Posted 23 September 2014 - 09:17 AM

Hi,

I am about to commit blasphemy (although not on this forum). I have had and EON 120 for about seven years and I have used it and used it and used it!!!!!! I love that scope and it sure treated me to amazing sights and many wows. However, since I got my C8 I have really not taken out my refractor more than a handful of times. I find that I prefer the views in the C8 to the refractor :banned:. I like the views of the planets and deep space more. Sure the stars are not as tight and the diffraction ring a tad brighter but the detail on everything is much easier to see. For example m13 is absolutely jaw dropping in the c8. It's nice in the refractor as well but not comparable to the C8. Same with the m57, the double cluster, m42 etc... In wide field views, of course, the refractor wins hands down.  And yes my sample of the EON is a great one. I had it tested by O.M.I. and it tested at a strehl of .96. I was told that the C8 would be about the equal of the refractor even though the C8 is much bigger but my experience (maybe it doesn't count for much because I am a low level amateur) has not been that way. I sure an 8 inch refractor would blow away the c8 but hey you can't easily get an 8 inch refractor unless you're plunking down serious $$.

Just my 2 cents

Clear Skies

Itz

 

 

Itz, it really just boils down to what you are observing and that's the core of this problem of why these discussions continue. Observers are not taking the time to educate beginners about what to look at as much as they are simply comparing M13. If I really wanted to observe M13, I'd just purchase a 20" and be done but have no desire to because nearly every telescope at a star party is pointed at M13. If an observer doesn't have specific types of deep sky targets in mind, then they won't have specific telescopes in their mind. This is why so many people in the forums continually have this debate. People just need to educate themselves more about what they are observing and select the right tools to do it. This discussion reminds me of a Formula One driver bringing their Formula One car to a Baja race and wondering why the wheels don't run well in the sand. 



#12 George Methvin

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Posted 23 September 2014 - 09:23 AM

Its funny how its works, my Eon 120mm ed  throws up some super sharp high contrast images plus cools down fast and gives great wide field views. Not a light scope but not to heavy, cost $2000 for ota only when I bought it years ago.  On the other hand my Meade 10 LX200 shows more but not as good with widefield view and it is bigger and heavier to take out and takes way longer to cool down,  plus it cost several thousand many  years ago.  Then you have my 12 Zhumell dob reflector that beats both on just about everything, great wide field views and planets look great.  The scope is easy to roll out and setup plus cools down faster then the 10 sct  but it is also fairly heavy but the scope only cost $699.99.  Some nights I take them all out at the same time and just go from one scope to the other those or fun nights.  I intend to keep them all LOL they all do a wonderful job of doing what they do best which is make me happy. Clear skies everyone.



#13 m1618

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Posted 23 September 2014 - 09:24 AM

Right tool for the right job. The SCT has the edge with light gathering power, which is usually your numero uno requirement. However, a smaller APO can produce incredible views. You may not go as deep as with a C8, but the trip will be well worth it. And an 80 - 100mm APO can produce the tack-sharp wide-field images an SCT just can't deliver.

 

I'm sorry, y'all; I gotta be honest...the older I get, the more I appreciate my small refractors. Not that I will ever stop using a C8. ;)

 

The solution? "Both." :lol:

I recently went out to do an outreach and one of the volunteer had brought out a 60mm spotting scope. Everyone was excited to view Saturn and of course they thought bigger the better and formed a line behind my 10" SCT (had no time to cool down). The crisp cool 60mm beat the 10" and the group didn't care to listen to my excuses of atmosphere this cool down time that. Only redeemed after showing M13. Pow! Try that little guy!

But yes, both!

Timely post as I was trying to sell off my scopes to fund a larger refractor. Hmmmm

 



#14 Brian Carter

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Posted 23 September 2014 - 09:34 AM

Right tool for the right job. The SCT has the edge with light gathering power, which is usually your numero uno requirement. However, a smaller APO can produce incredible views. You may not go as deep as with a C8, but the trip will be well worth it. And an 80 - 100mm APO can produce the tack-sharp wide-field images an SCT just can't deliver.

I'm sorry, y'all; I gotta be honest...the older I get, the more I appreciate my small refractors. Not that I will ever stop using a C8. ;)

The solution? "Both." :lol:


I don't own a refractor, but this is also my general observation. A long time ago I would take my Dob out to the field and feel superior to all the smaller Apos. After logging a lot of time and objects, the more I appretiate convenience and an enjoyable evening, and not so worried about going as deep as I can go. Right now that means a C8 rather than the Dob. But I notice the old guys on the field (totally not calling Unk an old guy) with the refractors and can see why they like them. No fuss and attractive views. Sometimes I think they are enjoying themselves more than the giant Dob crowd. That says a lot.

#15 Jon Isaacs

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Posted 23 September 2014 - 10:46 AM

Daniel and Rod hit the nail on the head, the right tool for the job.. What do you want to look at?  What's the best scope for looking at what you want to look at?  How much energy do you have?

 

For a shorter session, I often choose a refractor because the views are quite perfect, the effort needed is much less and there is plenty to enjoy. I don't try to do it all every night.

 

For a longer session, I set up two, sometimes three scopes. One is going to be a small refractor capable of some great low power views, one will be a large mirror based scope... If I want to look at the California nebula, or look at the Veil in its entirety, I  use the refractor, if I want to look at globular clusters, small galaxies and nebulae. I use a big scope..  There is no doubt that an 8 inch does a much better job on M13 than a 5 inch but double or triple the aperture of that 8 inch and suddenly there are M13s all over the place.

 

One issue that is important here are the relative  hassle factors.  The hassle factor for a 5 inch f/7.5 refractor and an 8 inch SCT are very similar. A fast 4 inch doesn't give up a lot to the 120mm but it can be grab and take you places  and show things that are not possible with the 120mm or the 8 inch.

 

So... It's not only the choosing the right tool for the particular job at hand, but also choosing the right set of tools so they compliment one another rather than compete with each other. Choosing scopes is not about this scope being better than that, it's about understanding the advantages and limitations/disadvantages and choosing accordingly.

 

Jon



#16 jgraham

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Posted 23 September 2014 - 11:42 AM

Yep, variety is the spice of life. Given enough time to cool down my 8" SCT is a thing of beauty and my primary scope for high resolution imaging, but I also dearly love my biggo 6" f/8 achro. The 6" cools down so darned fast and is so comfortable to use it is my go-to scope for relaxing evenings in the back yard. And yes, I also enjoy my little 60mm refractors. 

 

Fun stuff.



#17 ur7x

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Posted 23 September 2014 - 12:01 PM

Hi,

I am about to commit blasphemy (although not on this forum). I have had and EON 120 for about seven years and I have used it and used it and used it!!!!!! I love that scope and it sure treated me to amazing sights and many wows. However, since I got my C8 I have really not taken out my refractor more than a handful of times. I find that I prefer the views in the C8 to the refractor :banned:. I like the views of the planets and deep space more. Sure the stars are not as tight and the diffraction ring a tad brighter but the detail on everything is much easier to see. For example m13 is absolutely jaw dropping in the c8. It's nice in the refractor as well but not comparable to the C8. Same with the m57, the double cluster, m42 etc... In wide field views, of course, the refractor wins hands down.  And yes my sample of the EON is a great one. I had it tested by O.M.I. and it tested at a strehl of .96. I was told that the C8 would be about the equal of the refractor even though the C8 is much bigger but my experience (maybe it doesn't count for much because I am a low level amateur) has not been that way. I sure an 8 inch refractor would blow away the c8 but hey you can't easily get an 8 inch refractor unless you're plunking down serious $$.

Just my 2 cents

Clear Skies

Itz

 

 

People love to get all worked up about this, but frankly, I don't get it and I don't understand the level of misplaced passion a question/observation like this can generate.

 

My situation is very much like yours... I started with a 6" newt... it produced Meh, views, on lousy mount...  I moved to a 90mm Refactor... better views, same crummy mount... Now I have the 9.25 on a fairly good mount and I rarely look through the "smaller" scopes any more.

 

Having said that, my next purchase will almost certainly be a 152mm refactor.  I just love the old school look of those "big" refractors.   When asked I have no trouble recommending any OTA configuration...

Just so long as you look through it first. ;)



#18 rmollise

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Posted 23 September 2014 - 12:08 PM

Daniel and Rod hit the nail on the head, the right tool for the job.. What do you want to look at?  What's the best scope for looking at what you want to look at?  How much energy do you have?

 

For a shorter session, I often choose a refractor because the views are quite perfect, the effort needed is much less and there is plenty to enjoy. I don't try to do it all every night.

 

For a longer session, I set up two, sometimes three scopes. One is going to be a small refractor capable of some great low power views, one will be a large mirror based scope... If I want to look at the California nebula, or look at the Veil in its entirety, I  use the refractor, if I want to look at globular clusters, small galaxies and nebulae. I use a big scope..  There is no doubt that an 8 inch does a much better job on M13 than a 5 inch but double or triple the aperture of that 8 inch and suddenly there are M13s all over the place.

 

One issue that is important here are the relative  hassle factors.  The hassle factor for a 5 inch f/7.5 refractor and an 8 inch SCT are very similar. A fast 4 inch doesn't give up a lot to the 120mm but it can be grab and take you places  and show things that are not possible with the 120mm or the 8 inch.

 

So... It's not only the choosing the right tool for the particular job at hand, but also choosing the right set of tools so they compliment one another rather than compete with each other. Choosing scopes is not about this scope being better than that, it's about understanding the advantages and limitations/disadvantages and choosing accordingly.

 

Jon

 

Exactly, Jon...but...the more decrepit I get, the more I begin to think, "Hell, the views are pretty dang good in the 80mm, I'll just use her tonight!" :lol:

 

And, actually, to tell the truth, there is a lot you can see with a good 80. :)


Edited by rmollise, 23 September 2014 - 12:09 PM.


#19 JMW

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Posted 23 September 2014 - 12:34 PM

I keep an SVR90T refractor piggy backed on my C11 EdgeHD. They pair up nicely and live on a observatory pier so I don't have to set up things each time. 



#20 Ed Holland

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Posted 23 September 2014 - 12:59 PM

I'm a firm believer in giving every scope a chance. Each has a quality and character, each, as said before, fills different roles. That's why I enjoy my optical menagerie. If only I wasn't so exhausted, I could get out and view more :)



#21 StarMike8SE

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Posted 23 September 2014 - 01:06 PM

I have an Orion ST80 on top of my C9.25.  I use it as a finder scope, but also for general viewing.  I kind of get the best of both worlds on one mount   :D



#22 WesC

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Posted 23 September 2014 - 01:07 PM

Here is what I have come to realize after owning both a 4" APO refractor and an 11" Edge SCT...

 

4" APO Refractor Pros

  • Very lightweight (11lbs), My mount is very happy!
  • Built like a tank!
  • Very fast temperature acclimation
  • Wide field views, 4.5 degrees
  • Extremely sharp and well collimated views
  • Great contrast
  • Imaging with this lightweight scope at f/7 is much easier!
  • Not as affected by seeing
  • Has the best focuser I have ever used (FeatherTouch 3035 rotatable R&P)

 

4" APO Refractor Cons

  • Low aperture means most DSOs are only visible from a dark site (m13 is just a fuzzball, not many distinct stars)
  • Doesn't cut through light pollution very well.. bright skies at low magnification
  • Small image scale
  • Not enough aperture for good color rendition except under very dark skies
  • Needs high quality eyepieces to provide the best views
  • Very expensive per inch of aperture and to get good quality correction
  • Lots of astigmatism (from my eyesight) at large exit pupils (31mm Nagler)
  • Imaging requires an additional $325 reducer/flattener to eliminate aberrations.

 

 

Edge 11" SCT Pros

  • HUGE image scale (comparatively)
  • Cuts through LP better due to the large aperture and narrow FoV
  • Many DSOs look good in my red zone and just spectacular at a dark site. (M13 is clearly made of many thousands of stars!)
  • Great planetary and lunar detail and COLOR!
  • f/10 works really well with just about any eyepiece
  • No additional reducer required to image without aberrations.
  • Extremely well corrected... NO CA, NO field curvature, NO coma, NO astigmatism--even in my 31mm Nagler!

 

Edge 11" SCT Cons

  • HEAVY... 28lbs bare OTA
  • CO reduces contrasts
  • VERY affected by seeing conditions
  • Edge scopes require extremely fine collimation to give the best views
  • Collimation sucks.
  • Even when properly collimated, its no where as sharp as my APO, even at a similar magnification.
  • Mirror flop SUCKS
  • Narrow FoV (less than 1-degree) limits viewing many targets (M31 M45, etc...)
  • Long cool down time (even with TEMPest fans)
  • Did I mention the collimation issues?
  • Imaging with this heavy scope at f/10 is tricky and requires a better mount that I can currently afford.
  • Tube mechanics are fairly rudimentary and cheap.
  • Replacement focuser, active cooling fans add to the cost.

 

So the bottom line for me is that these two scopes compliment each other and give me a choice depending on how and what I want to view or image. I think that once I can sort out my Edge 11s collimation issues so that it HOLDs it all around the sky I will be very happy with it... because when its good, its REALLY good.

 

I think I also want a 5-6" APO and a big CDK... but that's a pipe dream for a long while. ;)



#23 MikeBOKC

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Posted 23 September 2014 - 01:50 PM

Yep, piggyback the 80ED on the CPC1100 for the best of both.



#24 MDavid

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Posted 23 September 2014 - 02:38 PM

Who are we kidding...If they made a light weight (but not too light) 36inch coma free f/1 scope (whether it be NEWT, CAT or Refractor) that we could use with our feet on the ground for less than $3K we'd ALL have one of those...but I digress...I love my C11 Edge (especially when binoviewing) and I'm still hunting for an 80mm APO to piggy back it with for "wide field" views. For AP (if I ever go there/crazy) I'll have a dedicated scope and mount as the optimal setups are best tailored for camera only views (speaking of blasphemy). :grin:



#25 moonnerd

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Posted 23 September 2014 - 03:51 PM

I like the approach of complemening the other scope.  I have a 130 triplet... would it take at least a C9.25 to be enough upgrade for visual lunar and planetary?  


Edited by moonnerd, 23 September 2014 - 04:43 PM.



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