Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

AT80EDT vs AT92EDT

refractor
  • Please log in to reply
17 replies to this topic

#1 JRM576

JRM576

    Lift Off

  • -----
  • topic starter
  • Posts: 5
  • Joined: 05 Apr 2020
  • Loc: Great White North

Posted 12 July 2020 - 06:33 PM

Hello CN members:

 

   I am looking to acquire my first refractor telescope and would appreciate some guidance in choosing the best one for my current (and possibly future) needs.  I am undecided between the AT80EDT and the AT92EDT.

 

   I understand that aperture is one of the more important aspects however, it is difficult to justify the +$1,000.00 price difference.  So I guess my question could be asked this way, would I be happy with the AT80EDT or should bite the bullet and go with the AT92EDT?  Is the cost difference really going to be apparent in the performance of these scopes if put side by side?

 

   My interests are both lunar/planetary and DSO's.  I eventually would like to explore the AP part of the hobby but for the time being, would be using one of these scopes for visual observation.

 

   I currently use a Celestron C5 and C90 as my primary telescopes.  They are mounted on an AZ GTi mount.  My preference is for the smaller form factors as I travel extensively for work and much prefer the most portable system I can have.  Cost is not the issue, other than spending more than I need or spending an excess of $$$ for a small bump in performance.

 

   I apologize if this question has already been asked.  I did do a search for this topic but did not find anything specific to this question.

 

   Thank you everyone in advance for your advice and experience.

 

JRM576



#2 photomagica

photomagica

    Mariner 2

  • *****
  • Posts: 289
  • Joined: 23 Jun 2013

Posted 12 July 2020 - 06:51 PM

I'm curious about the opinions on this as well. I have a really nice 90mm f5.5 achromat. I'd love to upgrade this to an apo and am wondering if I'd notice much difference in illumination and resolution if I went down to 80mm in an apo.

Thaks,

Bill



#3 Cometeer

Cometeer

    Vanguard

  • *****
  • Posts: 2,385
  • Joined: 07 Aug 2013
  • Loc: SF Bay Area, California or Illinois

Posted 12 July 2020 - 06:56 PM

Do you plan to use either scope on the AZ-GTi? If so, I’d say both are too heavy to use with that mount for AP. I use an AZ-GTi myself for AP, and would not put more than a 70mm apo on it. 



#4 JRM576

JRM576

    Lift Off

  • -----
  • topic starter
  • Posts: 5
  • Joined: 05 Apr 2020
  • Loc: Great White North

Posted 12 July 2020 - 07:03 PM

"Do you plan to use either scope on the AZ-GTi? If so, I’d say both are too heavy to use with that mount for AP. I use an AZ-GTi myself for AP, and would not put more than a 70mm apo on it."

 

   Not necessarily.  At the moment, I am more interested in the visual.  AP may come later.  I would consider upgrading the mount for this purpose.  The AZ GTi is simply the most portable goto that I can travel with.


  • Echolight likes this

#5 havasman

havasman

    Voyager 1

  • *****
  • Posts: 11,241
  • Joined: 04 Aug 2013
  • Loc: Dallas, Texas

Posted 12 July 2020 - 07:04 PM

I have an A-T115EDT and think the A-T scopes are great values with really good optics, ergonomics and mechanicals. I had enjoyed my scope > a year when the AT102ED came out. For visual, it's a better buy. Now if I were buying a refractor in that range I would very certainly go for the AT102EDL. It's going to really shake up that market. Astronomics has been watching and learning while marketing these very successful AT scopes and that scope's going to fly out the door.

 

The AT80EDT is, I'm sure, a very fine small scope at a reasonable price. The AT92EDT looks to me like an astrophotographer's tool and a scope for collectors with a stable of esoteric instruments who have given up on ever finding a vintage TBM/Brandon 94. I'd very much recommend you consider the AT102ED or AT102EDL instead.



#6 bobhen

bobhen

    Skylab

  • *****
  • Posts: 4,314
  • Joined: 25 Jun 2005

Posted 12 July 2020 - 07:28 PM

Will there be a performance difference between the 80mm and 92mm refractors?
YES: It won’t be earthshattering but depending on the target it should be noticeable.

 

Will that performance difference make you happy? Or will you be happier that you didn’t spend the extra money?

No one can answer that question.

 

You have some special requirements. And all I can tell you is, if it were “me” and I had to choose “between these 2 refractors”, I would select the 92mm.

 

I've owned a couple of high quality 80mm refractors and found the 80mm size wanting.

 

The 92 will give you more aperture, more potential resolving power and is really fast, which is perfect if you want to do some imaging. The 92 gets good reviews and is fairly compact.

 

You will have to upgrade your mount for imaging. If you want to take the scope on your travels, I’m sure you could find an alt/az mount that would be airline friendly.

 

Bob


  • stevew likes this

#7 Wildetelescope

Wildetelescope

    Surveyor 1

  • -----
  • Posts: 1,919
  • Joined: 12 Feb 2015
  • Loc: Maryland

Posted 12 July 2020 - 07:44 PM

If you look closely, you will see that the AT 92 does not have the EDT after it. It is a completely different animal. It is based on a Thomas Back design that astronomics commissioned years ago and I think uses a higher Grade of glass. I have the 80 edt. My friend has the 92. I like my 80 edt very much. It does what I wanted it for and I get excellent contrast on Jupiter and the moon. However it will show some very very small amount of color at mags greater than 50 X per inch. Not enough to bother me, but it is there. It shows color when imaging, again not enough to bother me. I do not think you can do better for the price. The 92 so far has not shown any color visually. We have not had a chance to run it through it’s imaging paces. Others report excellent results. There are several threads discussing the 92.

Hope that helps.

Jmd

#8 mikeinlehigh

mikeinlehigh

    Sputnik

  • -----
  • Posts: 46
  • Joined: 03 Jul 2020
  • Loc: Southwest Florida

Posted 12 July 2020 - 07:56 PM

I agree with Bob. I had a top of the line 80mm triplet. While i enjoyed many good visual sessions with it, I found the small aperture lacking. I'm sure it would have made a much better imaging scope. There are a ton of small aperture scopes sold so many people enjoy them. Of course they are far less demanding when it comes to the mount. You asked for opinions and that's all this is. When it comes to visual use, I say go for as much aperture as you can afford, mount and will use the most.



#9 JRM576

JRM576

    Lift Off

  • -----
  • topic starter
  • Posts: 5
  • Joined: 05 Apr 2020
  • Loc: Great White North

Posted 12 July 2020 - 10:15 PM

I have an A-T115EDT and think the A-T scopes are great values with really good optics, ergonomics and mechanicals. I had enjoyed my scope > a year when the AT102ED came out. For visual, it's a better buy. Now if I were buying a refractor in that range I would very certainly go for the AT102EDL. It's going to really shake up that market. Astronomics has been watching and learning while marketing these very successful AT scopes and that scope's going to fly out the door.

 

The AT80EDT is, I'm sure, a very fine small scope at a reasonable price. The AT92EDT looks to me like an astrophotographer's tool and a scope for collectors with a stable of esoteric instruments who have given up on ever finding a vintage TBM/Brandon 94. I'd very much recommend you consider the AT102ED or AT102EDL instead.

   I would agree that a 102 (4") scope would be great to have and possibly down the road, this would be the instrument that I would have if or when I am not travelling for work.  This is why I gravitated to the AT92.  It is as close as I could find to a 4" aperture while keeping the weight and length within certain limits.  It is a bit longer than my cases can accommodate and could possibly exceed TSA or CBSA carry on size limits.  It is a very nice scope though!

 

   Thank you for your advice.

 

Will there be a performance difference between the 80mm and 92mm refractors?
YES: It won’t be earthshattering but depending on the target it should be noticeable.

 

Will that performance difference make you happy? Or will you be happier that you didn’t spend the extra money?

No one can answer that question.

 

You have some special requirements. And all I can tell you is, if it were “me” and I had to choose “between these 2 refractors”, I would select the 92mm.

 

I've owned a couple of high quality 80mm refractors and found the 80mm size wanting.

 

The 92 will give you more aperture, more potential resolving power and is really fast, which is perfect if you want to do some imaging. The 92 gets good reviews and is fairly compact.

 

You will have to upgrade your mount for imaging. If you want to take the scope on your travels, I’m sure you could find an alt/az mount that would be airline friendly.

 

Bob

Hello Bob:

 

   This was what I was thinking.  I didn't want to find myself 'wanting' for something.  I am hoping that the refractor that I decide on will be my primary instrument for several years to come.

 

   I do realize the 'happy' part is impossible to answer even for me.  I appreciate your thoughts!

 

Thank you.


  • havasman likes this

#10 BravoFoxtrot

BravoFoxtrot

    Mariner 2

  • *****
  • Posts: 239
  • Joined: 11 Aug 2007
  • Loc: Palmer Divide, Colorado

Posted 12 July 2020 - 10:46 PM

A $1000 price delta is nothing to sneeze at...however...as Bob said, the AT92 is a noticeable improvement (not earth shattering) over an 80mm scope.  I sold my other 3” premium scopes after getting my AT92.  The optical quality is superb and it travels well.  Widefield observing and imaging are also strong suits.  It’s a versatile refractor.  The AT92 is a lifetime scope that will likely and always have place in your astronomy toolbox.  To me this decision is a no brainer.  YMMV.



#11 rkaufmann87

rkaufmann87

    Apollo

  • *****
  • Posts: 1,341
  • Joined: 07 Feb 2009
  • Loc: Folsom, CA

Posted 13 July 2020 - 12:34 AM

You are kind of off the the mark, the AT92 is really an Astrophotographers tools and not really a learning refractor. I have to agree that I think you would probably be happier with an AT102ED or if you really want to step up, the AT115EDT.  



#12 Wildetelescope

Wildetelescope

    Surveyor 1

  • -----
  • Posts: 1,919
  • Joined: 12 Feb 2015
  • Loc: Maryland

Posted 13 July 2020 - 01:31 PM

   I would agree that a 102 (4") scope would be great to have and possibly down the road, this would be the instrument that I would have if or when I am not travelling for work.  This is why I gravitated to the AT92.  It is as close as I could find to a 4" aperture while keeping the weight and length within certain limits.  It is a bit longer than my cases can accommodate and could possibly exceed TSA or CBSA carry on size limits.  It is a very nice scope though!

 

   Thank you for your advice.

 

Hello Bob:

 

   This was what I was thinking.  I didn't want to find myself 'wanting' for something.  I am hoping that the refractor that I decide on will be my primary instrument for several years to come.

 

   I do realize the 'happy' part is impossible to answer even for me.  I appreciate your thoughts!

 

Thank you.

  There have been a lot of good recommendations and I think all the scopes mentioned are good options depending on what you want to do, and your expectations of performance.  Sounds like a critical component of your decision making is portability.  Airline measurements sort of set the upper limits on what you can do, as you rightly state.  As I said, the 80 mm EDT has been a very nice performer for me.  It has been surprisingly good on the moon and planets.  I had a very nice session on the forth, where I was able to see quite a bit of detail at 170X  on Jupiter.  This included being able to see the red spot distinctly separated from its equatorial band, barges in the other equatorial band, polar cloud bands and the faintest hint of whorls and texture in the light region between the equatorial cloud bands.  Saturn looked nice and crisp.  I could clearly make out the Cassini division in the rings, and some cloud bands on the planet proper.  At 170X and lower, the only spurious color I saw on any solar system object (the moon) was clearly due to atmospheric dispersion.  For imaging you can see an example of M42 in one of my galleries that was taken with this scope.  There is a small bit of color around the bright stars.  If it bugs you, you can try using a UV/IR cut filter to minimize that.  I also find that the scope works with with my plossl and orthoscopic eyepieces as well as my wider field Televue EPs.  

 

A few folks have suggested considering several different 4 inch doublets.  The AT 102 ED's are getting really good feedback. I do not have one of those, but I do have a TV102 doublet, that performs similarly visually to what I described for my 80 mm EDT, but with the advantage of more aperture.  I have pushed that to 250X on the moon many times with excellent results.  However it does show a similar amount of color when imaging as the 80 mm EDT.  I have no doubt that the AT Doublets would be solid performers and worth your while if they meet your travel requirements.  

 

I agree with the others that the AT92 is primarily optimized for imaging with a Focal ratio of F5.5.  What this means to me, is that for visual use you might encounter a couple challenges.  In particular, usually with such fast scopes there is a certain amount of field curvature that distorts things at the edges.  Most imagers use a field flattener to correct for this.  For visual use this means  you are likely going to have a better experience with more expensive eyepieces, like the Televue Naglers, Ethos, Delos, etc... as opposed to less expensive designs like Plossls, orthoscopics, etc....  Secondly, because of that fast focal ratio, you have to go down to really small focal length eyepieces and/or use a barlow/powermate.  That said, my brief experiences with  my friends AT92 and my collection of TV eyepieces suggest it can be an excellent visual performer. the down side is that I could just about pay for the 92 if I sold 3 of my TV eps and a Powermate:-).  Of course if you already have a collection of the green and black beauties( or similar), then this is not an issue.

 

The other factor in this is that as you get into this you are going to eventually want to see what more aperture gives you.   My first refractor was an 80 mm Doublet.  It was a fine scope, with excellent optics.  I sold it because at the time, my eyepiece collection was limited and I could not get out of it what I wanted, and I was not imaging as much.   Having come full circle, I am imaging more and I have a MUCH better lineup of EP's that can take advantage of the shorter focal length(even an F6 is still short).  I have to agree with everyone that a 4 inch refractor is really a good place to start as a beginner if it meets your travel criteria.  It is a good combination of aperture and portability.  I love my 4 inch refractor.  It grabs enough light to make bright DSO's interesting even in my orange/red zone.   It will not pass the Carry on test, but it is easily transportable in a car.  It is small enough to use on a relatively light weight Alt Az mount like a twighlight 1 or 2 or similar.  The AT 102 is a bit shorter at F7,(my 4 inch is an F8.8) which will make it even more portable, although it might show a little bit more color.  

 

Anyway, those are my experiences.  Hope this helps with your decision making.   One last thing I would say is that if the refractor bug really bites you, this first one will likely not be your last.:-). 

 

Cheers!

 

JMD


  • BFaucett and Lookitup like this

#13 Wildetelescope

Wildetelescope

    Surveyor 1

  • -----
  • Posts: 1,919
  • Joined: 12 Feb 2015
  • Loc: Maryland

Posted 13 July 2020 - 01:41 PM

You are kind of off the the mark, the AT92 is really an Astrophotographers tools and not really a learning refractor. I have to agree that I think you would probably be happier with an AT102ED or if you really want to step up, the AT115EDT.  

I think ones satisfaction with the visual performance of the AT 92 depends on your eyepiece collection:-).   That said, in this range 10 mm makes a significant difference with respect to light gathering.    All about trade offs.

 

JMD 



#14 gwlee

gwlee

    Vanguard

  • *****
  • Posts: 2,074
  • Joined: 06 Sep 2015
  • Loc: 38N 120W

Posted 13 July 2020 - 10:58 PM

Hello CN members:

 

   I am looking to acquire my first refractor telescope and would appreciate some guidance in choosing the best one for my current (and possibly future) needs.  I am undecided between the AT80EDT and the AT92EDT.

 

   I understand that aperture is one of the more important aspects however, it is difficult to justify the +$1,000.00 price difference.  So I guess my question could be asked this way, would I be happy with the AT80EDT or should bite the bullet and go with the AT92EDT?  Is the cost difference really going to be apparent in the performance of these scopes if put side by side?

 

   My interests are both lunar/planetary and DSO's.  I eventually would like to explore the AP part of the hobby but for the time being, would be using one of these scopes for visual observation.

 

   I currently use a Celestron C5 and C90 as my primary telescopes.  They are mounted on an AZ GTi mount.  My preference is for the smaller form factors as I travel extensively for work and much prefer the most portable system I can have.  Cost is not the issue, other than spending more than I need or spending an excess of $$$ for a small bump in performance.

 

   I apologize if this question has already been asked.  I did do a search for this topic but did not find anything specific to this question.

 

   Thank you everyone in advance for your advice and experience.

 

JRM576

The difference in the views between 80mm and 92mm is noticeable in most circumstances, but not a  “wow” difference. One of the 4” AT scopes will offer a more noticeable improvement and cost less than the AT92.


  • BFaucett likes this

#15 Echolight

Echolight

    Viking 1

  • -----
  • Posts: 624
  • Joined: 01 May 2020
  • Loc: Texas

Posted 14 July 2020 - 11:15 AM

I would love to have a 90-ish apo doublet for a grab-n-go, even though it would likely never see air travel. Seems about the best fit as far as max size and weight to be stable on a light alt/az mount.

 

But I'll be happy with whatever 80 ED I end up with.



#16 kmparsons

kmparsons

    Ranger 4

  • -----
  • Posts: 314
  • Joined: 07 Jun 2007
  • Loc: Texas

Posted 14 July 2020 - 11:34 AM

I have had the AT 92mm for over a year now, and I am very happy with its optical and mechanical excellence. I own an 80mm triplet from Stellarvue, which is also excellent, but the 92mm is definitely a step up visually. It is entirely worth the $1800 price tag, IMO. It is compact, but it is quite a chunk, and I would not want to use it for an airline carry-on scope. An 80mm should fit nicely in your carry-on bag and still leave plenty of room for socks and underwear. 



#17 JRM576

JRM576

    Lift Off

  • -----
  • topic starter
  • Posts: 5
  • Joined: 05 Apr 2020
  • Loc: Great White North

Posted 18 July 2020 - 07:04 AM

   Thank you to everyone for your experience and insight, it has been very helpful.  You have confirmed what my assumption of the performance difference would be which has helped me decide on the instrument that I will purchase.  Just in case anyone is wondering, it will be the AT92.
 

   I believe this scope will serve me well for many years and I too would agree, that this will not be the only refractor telescope I will possess in my collection.
 

  Thanks again for the great advice!

 

Clear skies,

 

JRM576


  • BravoFoxtrot likes this

#18 BravoFoxtrot

BravoFoxtrot

    Mariner 2

  • *****
  • Posts: 239
  • Joined: 11 Aug 2007
  • Loc: Palmer Divide, Colorado

Posted 19 July 2020 - 08:00 PM

Well done!


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics





Also tagged with one or more of these keywords: refractor



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics