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AT92 vs AT102EDL for visual only

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#1 TNmike

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Posted 11 June 2020 - 09:36 AM

Which would you go with, and why??? Each has their pluses, and a couple minuses. Let the games begin.



#2 petert913

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Posted 11 June 2020 - 09:41 AM

Always aperture in my book


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#3 Jond105

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Posted 11 June 2020 - 09:55 AM

I’d go 102. The aperture would be not too different in my book. I still have a 90mm and a 100mm. But, the 102 with the longer focal length and f ratio may benefit. No major field curvature. Easier to get to higher powers without the use of a Barlow. Just my thought. 


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#4 Spikey131

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Posted 11 June 2020 - 09:56 AM

Since no one has looked through the AT102EDL, it is currently hard to say.

 

If the optical quality turns out to be as-expected-excellent, then the only advantage of the 92 for visual use would be its compact size.  And the cool factor.


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#5 rustynpp

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Posted 11 June 2020 - 01:12 PM

Between these two, you're basically deciding whether you want to optimize on compactness and widefield capabilities or aperture and high-mag capabilities. They'll both do either well, fortunately, but like I said, it's a question of optimization. It's a personal decision, and also depends on what other scopes you have.

 

When I bought my Z103 (an FPL-53 doublet) I did consider the AT92, which was in pre-production at the time. But to me the former seemed like the more balanced scope, and since it was my only scope at the time, I decided to go with the 4" f7. 

 

I have since added an 80mm f7.5 FPL-53 doublet. You could make the argument that the AT92 could take the place of both, but of course you then lose the flexibility of having two scopes that each do different things really well. If I were to get a single scope to replace both, it would probably be a Tak FC-100DC rather than a super-fast triplet.


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#6 RAKing

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Posted 11 June 2020 - 02:42 PM

I know the 102EDL won't be available until roughly Labor Day, so none of us can say for sure how well it works.  The little 92 triplet looks like a great travel and imaging tool, but I don't know its availability.

 

Anyway, my choice would be the 102.  The specs for the new 102 sound great and unless I am forced to use a smaller refractor (like for medical reasons), the bigger aperture will always be my choice.

 

Cheers,

 

Ron


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#7 russell23

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Posted 11 June 2020 - 02:51 PM

One thing to keep in mind for visual is the extreme strain the field curvature of the 92mm will put on eyepiece edge performance.  

 

I learned this with the WO Z61 f/5.9.   In theory the little scope could provide a 6 deg field, but due to the field curvature I could not find an eyepiece wider than a 3.0 deg TFOV (18.2mm DeLite) that provided good edge performance.

 

I remember when I looked through the previous generation of the 92mm TMB that the field curvature was pretty significant. 

 

The 80mm f/7 SV Access was better for field curvature but still the 18.2mm DeLite was the widest TFOV I could get that was satisfactory (2.0 deg).   

 

Obviously if you have a 31mm Nagler you should be in better shape. 


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#8 Jond105

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Posted 11 June 2020 - 03:09 PM

I think most saying they aren’t sure how the 102EDL will be, should just look at reviews of the Stellarvue access 102 that has the same glass being used, and I think the same focuser. 


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#9 kmparsons

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Posted 11 June 2020 - 03:16 PM

I have had the AT 92mm for a year now, and I have enjoyed it immensely. It is optically and mechanically excellent, and a breeze to set up and use. Ironically, the only time I have noticed field curvature was when using the Orion "Ultra Flat Field" 2" 24mm eyepiece. Even then, it was only noticeable around the outer 10% or so of the image. An f/7 would likely have less field curvature than the 92mm at f/5.5. However, for a compact scope that is easy to pack off to a dark sky site, or for grab 'n' go, the 92mm is pretty close to ideal for me. 


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#10 sunnyday

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Posted 11 June 2020 - 03:16 PM

if it is true that the aperture is master, so the 102 mm.
but if I'm not mistaken the 92 is a triplet.
and 102 a doublet.
can we really make a comparison doublet, triplet?

 

I'm asking the question.


Edited by sunnyday, 11 June 2020 - 03:18 PM.

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#11 Jond105

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Posted 11 June 2020 - 03:21 PM

if it is true that the aperture is master, so the 102 mm.
but if I'm not mistaken the 92 is a triplet.
and 102 a doublet.
can we really make a comparison doublet, triplet?

 

I'm asking the question.

I think you can, depending on the quality of glass without a doubt. Especially when other accounts are, the focal ratio, as me and Russel mentioned, the curvature in one will be more severe than the other. FCD100 and lanthanum pairing will be a great combo that could put to test to other triplets. The SW120ED gets compared a lot to the AT115 triplet as well. Though the 92 will have great color correction, is the field curvature worth it is more of a question I would ask. 


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#12 Spikey131

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Posted 11 June 2020 - 04:11 PM

if it is true that the aperture is master, so the 102 mm.
but if I'm not mistaken the 92 is a triplet.
and 102 a doublet.
can we really make a comparison doublet, triplet?

 

I'm asking the question.

Yes, it is reasonable to compare color fidelity of an f/5.5 triplet and an f/7 doublet.  For visual use, I expect that they would be practically indistinguishable. Of course, like I stated above, we don’t know yet about this 102.



#13 Jon Isaacs

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Posted 11 June 2020 - 04:27 PM

A few comments:

 

Field curvature is considerably worse with a 60 mm F/6 than a 92 mm F/5.5.

 

I don't really worry too much about field curvature, it comes with territory for those 6° fields in an ST-80. Of course the NP-101 does 4.9° flat with the 41 mm Panoptic so that's like money in the bank.

 

I'd go with the 4 inch F/7..  I'm sure the 92 mm F/5.5 is a very give scope but I like F/7 better than F/5.5 in an all around scope. One thing I've learned with the NP-101 is that it gives near perfect views across the field but I have to be using my Naglers and the like because ,F/5.4 is fast enough to bring out the astigmatism if it's there.

 

That and the full 4 inch aperture. 

 

Jon


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#14 sanbai

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Posted 11 June 2020 - 06:09 PM

One paper I would also go for the 4" doublet. Less field curvature, more than good enough color correction, shorter cooling than a Triplet.

I may actually go for one in the future, may be the TS version whenever I move back to Europe. Or the 6"??....

Back to topic!

Another aspect is that light pollution does not go well with the wide fields, large exit pupil of the f/5.5 refractor. A 3-5" f/5.x with a flat field in a dark site can be a joy. In suburban skies, without flat field, not really.

I must add that field curvature is not an issue for me using the SW80 ED f/7.5 doublet and the Nagler 31. If there is any field curvature, inaccurate eye positioning and my small astigmatism or whatever else just hide it to me. So far happy with what I see.

#15 Passerine

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Posted 11 June 2020 - 07:03 PM

My 2 cents...

These 2 scopes are almost too different to compare.  My personal preference for a visual instrument would be the AT102EDL (based on the solid reviews of the AT102ED with lesser glass, but also really all Astronomics refractors).

 

I've always been interested in the NP101 in part because reports from users like Jon above indicate it may be the best wide or "rich" field portable visual instrument when it comes to sharp stars all the way to the edge of the circle.  I came close to getting a used NP101 once, but I was too slow...  I've often wondered after so many years, why there do not seem to be any more affordable "NP101 clones" out there.  I'm getting off topic here, but I'll just say this:  More than either the AT102EDL or  the AT92, I would be interested in an "Astronomics 102mm Petzval NP101 clone"... I doubt that would be the official name. smile.gif

 

Dave


Edited by Passerine, 11 June 2020 - 07:09 PM.

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#16 Spikey131

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Posted 11 June 2020 - 07:14 PM

My 2 cents...

These 2 scopes are almost too different to compare.  My personal preference for a visual instrument would be the AT102EDL (based on the solid reviews of the AT102ED with lesser glass, but also really all Astronomics refractors).

 

I've always been interested in the NP101 in part because reports from users like Jon above indicate it may be the best wide or "rich" field portable visual instrument when it comes to sharp stars all the way to the edge of the circle.  I came close to getting a used NP101 once, but I was too slow...  I've often wondered after so many years, why there do not seem to be any more affordable "NP101 clones" out there.  I'm getting off topic here, but I'll just say this:  More than either the AT102EDL or  the AT92, I would be interested in an "Astronomics 102mm Petzval NP101 clone"... I doubt that would be the official name. smile.gif

 

Dave

Because good Petzvals are difficult (=expensive) to make.  Requires some expertise and attention to detail.  If they could make a cheap clone, they would.

 

The NP101 is one of the most amazing optical devices I have peered through and it never disappoints.


Edited by Spikey131, 11 June 2020 - 07:14 PM.

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#17 sanbai

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Posted 11 June 2020 - 10:46 PM

An NP101 and the AT102EDL are different beasts. The AT, not only for its price, will satisfy more people.

The TV Nagler-Petzval is a niche instrument. Collimation is an issue you may have to deal with (mostly sending it to TV). It calls for premium eyepieces. And it needs dark skies to shine. Add the price: buying one is a very serious investment. It's a great telescope (I would like one!), But it isn't justified for everybody.

If you accept a bit smaller true field and smaller exit pupil (and you may have to just because the pollution isn't nice), the AT could deliver (on paper) the same level of satisfaction, if not more.

#18 BravoFoxtrot

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Posted 11 June 2020 - 11:03 PM

The NP101 comparisons are tough and not especially relevant. My NP101 beats my AT92 in almost everything except portability. However, the differences, albeit subtle, are noticeable when compared side by side.*

The new AT102 in an intriguing and attractive option. What are your primary uses for the scope? What other scopes do you have and how does the new scope fill a void or augment what you currently have?

To be honest, the NP101, the new AT, an AT92, or any number of premium options...no wrong choices...only better choices based on present requirements or desires. Every option mentioned will provide exceptional views and many nights of enjoyment.
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#19 areyoukiddingme

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Posted 11 June 2020 - 11:18 PM

My 2 cents...

These 2 scopes are almost too different to compare.  My personal preference for a visual instrument would be the AT102EDL (based on the solid reviews of the AT102ED with lesser glass, but also really all Astronomics refractors).

 

I've always been interested in the NP101 in part because reports from users like Jon above indicate it may be the best wide or "rich" field portable visual instrument when it comes to sharp stars all the way to the edge of the circle.  I came close to getting a used NP101 once, but I was too slow...  I've often wondered after so many years, why there do not seem to be any more affordable "NP101 clones" out there.  I'm getting off topic here, but I'll just say this:  More than either the AT102EDL or  the AT92, I would be interested in an "Astronomics 102mm Petzval NP101 clone"... I doubt that would be the official name. smile.gif

 

Dave

While I realize you are talking about new scopes, I think it's worth pointing out that an older Televue 101 can be found for around 1300 to 1500. From reports I have read performance (for visual) is very close to the current NP.

 

You'll most likely get a single speed focuser (unless upgraded) and the length/weight is a bit higher.


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#20 Jethro7

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Posted 12 June 2020 - 12:04 AM

Which would you go with, and why??? Each has their pluses, and a couple minuses. Let the games begin.

Hello TNmike,

I bought a used like new AT102 ED , a few weeks ago. I had it out tonight and boy I am impressed with this little scope and the AT102 EDL will have better lenses than mine. All I can say is if that's true the AT102 EDL will be outstanding because the AT102ED is its self a pretty awesome telescope.The  manufacturing quality on these scopes is very nice. And the focuser is sturdy and smooth. All I can say is my AT102ED, performs way above its price class. At $599.00  If you go for the AT102 EDL, I hope that  you post a review here on CN.

 

HAPPY SKIES AND KEEP LOOKING UP Jethro


Edited by Jethro7, 12 June 2020 - 12:06 AM.

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#21 dusty99

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Posted 12 June 2020 - 09:32 PM

Yes, 16" with the dewshield down is pretty compact.  That's also why I'm interested in it.

 

 

I have had the AT 92mm for a year now, and I have enjoyed it immensely. It is optically and mechanically excellent, and a breeze to set up and use. Ironically, the only time I have noticed field curvature was when using the Orion "Ultra Flat Field" 2" 24mm eyepiece. Even then, it was only noticeable around the outer 10% or so of the image. An f/7 would likely have less field curvature than the 92mm at f/5.5. However, for a compact scope that is easy to pack off to a dark sky site, or for grab 'n' go, the 92mm is pretty close to ideal for me. 



#22 BillP

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Posted 12 June 2020 - 09:42 PM

Which would you go with, and why??? Each has their pluses, and a couple minuses. Let the games begin.

Shouldn't the question be what it is that you are looking for in a scope and which do we think fits that better?  If I tell you what I like about each then that only pertains to me.  It all really depends on what you want to maximize and what you want to compromise. 

 

In a nutshell:

 

With the 92 you are maximizing /weight/compactness and MaxTFOV capability, and compromising ease of focal ratio on eyepieces, light gathering, resolution, probably cool down speed since a triplet, field curvature; 

 

With the 102 you are maximizing light gathering, resolution, ease of focal ratio on eyepieces, field curvature, probably cool down, and compromising weight/compactness, MaxTFOV capability.

 

Mounting probably the same, visually CA probably not different enough to matter but is something that needs to be investigated more deeply after field reports on the new scope arrive.

 

PS - if you are an open cluster fan, then there is a lot of difference visually between a 92 and a 102 based on my direct comparison of those two apertures, enough so that after being used to 102, I would not compromise down to 92 as the form factor reduction is really just not very much.


Edited by BillP, 12 June 2020 - 09:44 PM.

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#23 TNmike

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Posted 13 June 2020 - 11:34 AM

Thanks everyone for your comments. I made my question rather general so as to get the broadest range of opinions, whereas if I told you my situation the comments might have been "steered" more. In any case here is my lot in life.

 

With some sadness, I have sold my SW120ED/DSV-3/Oberwerk tripod combination. My old body is going down hill faster than I would like, and that combo was a little more than I liked to have to handle. Plus, I live in a doublewide and the doors are somewhat narrow, thus not making it easy to get it all out of my man cave into the great outdoors. Therefore I determined it would be wise to downsize to a setup that is about 2/3 the size and weight of the 120ED combo, max. I thought that would hopefully work for the long haul. I presently have an AT60ED which isn't going anywhere soon, it's lots of fun. But I was thinking a larger scope, 4" max, for my "big" scope. It seems I can reach my 2/3 goal at that size. I'm visual (lunar-planetary primarily, but also DSOs) only, but do want a really good affordable ED/APO, therefore I had been looking at the AT102EDL and AT92. I actually have the AT102EDL on order, but wanted to do one final gut check as both models will be in at Astronomics at the same time, and could change my mind and order if need be.

 

The bottom line is I will stay with the AT102EDL. After seeing all the comments and considering all the pros and cons, the 102 wins for my situation, but by only by a little. The shorter length and lighter weight of the 92 are attractive, but the longer cool down and price are negatives. The short FL giving more FC is not a big problem as I have good eyepieces and already have some experience with it from the AT60ED. The CA of either scope should be virtually undetectable except to the most experienced eyes. I am confident from the magic they did with the AT60ED that CA will not be a problem in the AT102EDL. The extra 10mm aperture will certainly be helpful too. So, I've got to patiently wait a few weeks until she arrives.

 

Again, thanks to all; good discussion.


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#24 Jond105

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Posted 13 June 2020 - 11:38 AM

Thanks everyone for your comments. I made my question rather general so as to get the broadest range of opinions, whereas if I told you my situation the comments might have been "steered" more. In any case here is my lot in life.

 

With some sadness, I have sold my SW120ED/DSV-3/Oberwerk tripod combination. My old body is going down hill faster than I would like, and that combo was a little more than I liked to have to handle. Plus, I live in a doublewide and the doors are somewhat narrow, thus not making it easy to get it all out of my man cave into the great outdoors. Therefore I determined it would be wise to downsize to a setup that is about 2/3 the size and weight of the 120ED combo, max. I thought that would hopefully work for the long haul. I presently have an AT60ED which isn't going anywhere soon, it's lots of fun. But I was thinking a larger scope, 4" max, for my "big" scope. It seems I can reach my 2/3 goal at that size. I'm visual (lunar-planetary primarily, but also DSOs) only, but do want a really good affordable ED/APO, therefore I had been looking at the AT102EDL and AT92. I actually have the AT102EDL on order, but wanted to do one final gut check as both models will be in at Astronomics at the same time, and could change my mind and order if need be.

 

The bottom line is I will stay with the AT102EDL. After seeing all the comments and considering all the pros and cons, the 102 wins for my situation, but by only by a little. The shorter length and lighter weight of the 92 are attractive, but the longer cool down and price are negatives. The short FL giving more FC is not a big problem as I have good eyepieces and already have some experience with it from the AT60ED. The CA of either scope should be virtually undetectable except to the most experienced eyes. I am confident from the magic they did with the AT60ED that CA will not be a problem in the AT102EDL. The extra 10mm aperture will certainly be helpful too. So, I've got to patiently wait a few weeks until she arrives.

 

Again, thanks to all; good discussion.

Will be more than a few weeks. They won’t arrive to be shipped out until Labor Day. Though I think you made a good choice. 


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#25 TNmike

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Posted 13 June 2020 - 11:43 AM

Few weeks, well, yeah, three months??? I do hope not any later than about Labor Day, as I would like to have it in time for the best of the Mars opposition window. But if it's later I'll get to find out what the mighty AT60ED can really do, instead, lol.


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