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AP130GTX vs TEC140 side by side viewing

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#1 DeanS

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Posted 17 February 2017 - 09:59 AM

Looks like tonight will be my first light with the new AP130GTX and I have it mounted next to the TEC140 for direct comparison.  Since I am mostly an imager I don't really know exactly how to compare other than what looks good to me.  I have a friend coming over who is a little more into visual than me so having two sets of eyes will be helpful.

 

I have a Tak and Williams Optic diagonal so I should probably use the same diagonal with each scope to be fair as the Tak is likely much better than the other.  However I am not sure about how to compare views, as in should I have the same power in each scope, or the same eyepiece?  I have Ethos down to 8mm, and a Delos 4.5mm.  Tec is F/7 980mm and the AP is F/6.3 820mm so I except the AP to be slightly brighter yet smaller using the same eyepieces.

 

Anyways, give me some suggestions on how best to do this in a more scientific way than just what looks best.  After all is done; "There can only be one."  ( yes taken from the Highlander :) )

 

Thanks

Dean

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Edited by DeanS, 17 February 2017 - 10:01 AM.

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#2 starbob1

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Posted 17 February 2017 - 10:40 AM

This has been done quite a bit if you google it. Both are killer scope's. One is way overpriced and one is slightly over priced. No 2 scope are alike so if one does provide better views it really does not really say much about the whole line of that scope. Should be fun. I wish I had my Old FS 102 to compare to my new FC-100 DF. I bet the 140 being larger aperture does well. By the way I think all premium scopes are over priced Tak AP Tec. So I am just not picking on AP. Got to pay to play though.



#3 Adam S

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Posted 17 February 2017 - 11:02 AM

I had a TEC 140 and AP 130EDFGT at the same time. I felt that M13 and M22 showed more stars in the TEC otherwise personal choice.  I kept the AP because it's so small and easy to move in and out of my car/house/garage.  Much heavier than I'd thought it would be but that's the price for thermal stability in photography.  

 

With the differences in focal length I'd think that the best way to do an apples to apples comparison is with the same diagonal, same ep lines (only Delos, only Nagler, only Baader etc) and varying the focal length eps.  Hopefully there's a quality zoom in the mix that can go back and forth.  I've read that people see color in the TEC 140. I didn't, I also do all of my observing in focus, I don't care what happens out of focus.

 

The AP and an older Tak FC 100 are my forever scopes.  The AP is as much a pleasure to look at as it is to look through, it represents a piece amateur astronomy history and that means a lot to me.  

 

Both are expensive but worth it if you can afford the price of admission (the market is currently loaded with refractors that have excellent optics for much less money).  The mechanics are great with a notable edge to the AP, the only people who question the AP  build vs competition's build haven't used one so who cares what they think.  With that price tag comes a level of service from Roland and or Yuri that no producer matches. 


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#4 daveCollins

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Posted 17 February 2017 - 11:24 AM

I've tried comparing scopes side by side. I don't think it is possible to do any sort of objective comparison. 

 

I am no longer of the opinion that doing sope comparisons is important. Instead, I use a scope and based on how things look over different viewing sessions, I can conclude whether or not I like the scope and enjoy the views it provides.

 

To put it differently, if someone says I've used a TEC 140 and GTX 130 side by side and the TEC is better. I'd say, who cares. I like my scopes and it doesn't matter what someone else thinks as to how one copy of a GTX compares to one copy of a TEC 140 in specific conditions as evaluated by people I don't know and so whose abilities are completely unknown to me.

 

Instead, if you were to report back as to how much you like your scope and what you looked at, that would be meaningful to me. I'd simply enjoy hearing about it and experiencing enthusiasm indirectly.


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#5 DeanS

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Posted 17 February 2017 - 11:37 AM

I've tried comparing scopes side by side. I don't think it is possible to do any sort of objective comparison. 

 

I am no longer of the opinion that doing sope comparisons is important. Instead, I use a scope and based on how things look over different viewing sessions, I can conclude whether or not I like the scope and enjoy the views it provides.

 

To put it differently, if someone says I've used a TEC 140 and GTX 130 side by side and the TEC is better. I'd say, who cares. I like my scopes and it doesn't matter what someone else thinks as to how one copy of a GTX compares to one copy of a TEC 140 in specific conditions as evaluated by people I don't know and so whose abilities are completely unknown to me.

 

Instead, if you were to report back as to how much you like your scope and what you looked at, that would be meaningful to me. I'd simply enjoy hearing about it and experiencing enthusiasm indirectly.

I fully expect them both to be outstanding, so I do agree it has to be hard to judge a winner.  If the 130 is close to the 140 on similar objects it will get the edge since it is smaller in size and easier to handle.

 

Dean


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#6 dr.who

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Posted 17 February 2017 - 06:55 PM

Use the same diagonal on both. Try to get to the same or as close to the same magnification on both.
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#7 Blueox4

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Posted 17 February 2017 - 08:05 PM

For imaging the edge has to go to the GTX. I am curious what you think of the AP focuser compared to the FT 3545 in the TEC? I sold my TEC140 when I received my AP130 GTX a few weeks ago and almost imediately regretted it because I just felt the FT focuser was better and I liked the collet lock too but I'm a visual observer. I solved that by selling the AP130GTX and ordering a TEC160 which I should have in a few weeks. Service from both AP and Yuri is the best it can be. I wish you the best with your decision but for imaging and thus double duty too far visual the AP would be best. I'd say if you were visual only go with the TEC. 


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#8 DeanS

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Posted 17 February 2017 - 10:54 PM

A quick summary after a few hours tonight with a couple other friends.  Can't pic a winner.  Just when you thought one looked better, then went back to the other, you changed your mind.  Too close to call.  The AP might have had a slight edge on contrast but that might have been our imagination.  

 

AP focuser is fine once I loosened it a bit.  But I agree that the FT focuser just feels the best.

 

Used mostly an Ethos 10 in the Tec and a 8 Ethos in the AP which both gave right at 100 power so a pretty close comparison.  Seeing was not good so mostly did clusters and doubles.

 

One of the guys took notes and is going to do a quick write up on the objects we observed.

 

Will have to try some imaging next, which the AP should be a tad better on correction.

 

Dean



#9 olivdeso

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Posted 17 February 2017 - 11:05 PM

The draw tube of the AP focuser is made of steel. It is stonger than the competitors. The FT 3,5" is excellent, the AP focuser is still a little bit better to me, like many things on AP refractors. A lot of small improvements everywhere compared to competitors tha makes the AP scope above the rest of the world, for photographic use at least.

Sure they are expensive, but you pay for what you get : a unique masterpiece of optics, a state of the art astrograph, resulting of decades of optimization.

 

The 4" AP focuser is a rock. Second to none. In fact all the mechanical side of AP products are in another league compared to competitors. This is why they are so unique. And it works on the field !

 

That said, the TEC optics are awesome too at least for visual use.

 

Selling a 130GTX to buy a TEC160FL makes sense for visual use only. The 160FL is compact, lightweight and the focuser is more than stiff enough for visual use (and also for most of cameras). The best current choice to me in that range.

 

I had both the TEC160ED and the AP155EDF/7 at the same time. They are completly different telescope. The AP155/7 with its 4" massive focuser and 4" correctors and reducer (155TCC) is optimized for astrophotography. The machined baffling is awesome for instance.

 

The tech 160ED is more "simple" but also give super sharp and contrasty views.



#10 Daniel Mounsey

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Posted 18 February 2017 - 01:45 AM

I've tried comparing scopes side by side. I don't think it is possible to do any sort of objective comparison. 

 

I am no longer of the opinion that doing sope comparisons is important. Instead, I use a scope and based on how things look over different viewing sessions, I can conclude whether or not I like the scope and enjoy the views it provides.

 

To put it differently, if someone says I've used a TEC 140 and GTX 130 side by side and the TEC is better. I'd say, who cares. I like my scopes and it doesn't matter what someone else thinks as to how one copy of a GTX compares to one copy of a TEC 140 in specific conditions as evaluated by people I don't know and so whose abilities are completely unknown to me.

 

Instead, if you were to report back as to how much you like your scope and what you looked at, that would be meaningful to me. I'd simply enjoy hearing about it and experiencing enthusiasm indirectly.

 

That's absolutely absurd Dave. I 110% guarantee, if an experienced and knowlagable observer takes two samples of the same model, one can discern variation of performance. In the end, one sample will yield different contrast than the other in the right circumstances. The observers failure to do so may be for a number of reasons they don't understand. Give me a constructive reason how you could say such a thing. I greatly appreciate when I know something is extra special. Perhaps others may not. 


Edited by Daniel Mounsey, 18 February 2017 - 10:13 PM.

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#11 daveCollins

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Posted 18 February 2017 - 03:07 AM

Daniel, I worded my comments carefully and they explain how I feel. My comments are my own subjective feelings. There is no right or wrong to what I've said since I am talking about myself. Others may read what I've written and have the same feelings themselves and others may not feel the same as I do.

 

Humans lack the ability to see things as they are as a general statement. When we have a conscious experience, it is the result of high level abstractions performed in the brain. These abstractions are controlled by processes in the brain that are out of our control and prevent us from seeing the true nature of the source information.

 

For example, look at the Checker Board Optical illusion: Checker Board Illusion

 

In this case, the "B" is on the same color square as the "A". If you don't believe it, make some cutouts of paper and mask everything but the "A" square and "B" square.

 

What this shows is that even when you know that you are NOT perceiving the actual shades of gray as they are, you still can't see that the two squares are the same shade of gray. Your brain has taken over and you aren't able to see the stimulus as it hit your eye.

 

I could go into a long description of my various feelings, but that would be pointless and inappropriate. The example above is one of the many reasons for my comments ... I don't think one can perform an object evaluation of two similar scopes side by side.

 

EDIT:

  • By the way, it may be easier to use a snipping tool and snip out the "A" square and "B" square and paste them into a document side by side. The result is dramatic. They are exactly the same shade of gray.
  • As you can see, even in such a dramatic example you cannot see that there is NO contrast difference between the two squares. So this calls into question ones ability to see subtle contrast differences in anything.
    • So to say one can objectively see subtle differences in contrast between two scopes is not consistent with the facts as to how our nervous systems work.

Edited by daveCollins, 18 February 2017 - 01:40 PM.

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#12 t.r.

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Posted 18 February 2017 - 06:21 AM

Perhaps not Dave, but throw both scopes on an interferometer or compare their imaging abilities and I can objectively say, there will be differences that may or may not be perceived visually! ;)  I can submit a data point for the discussion or rather, three...myself and two others had both the TEC 140 and AP 130 GT at the same time for direct comparisons (I did a comprehensive 5 month comparison) and for whatever subjective reasons, we all chose the AP over the TEC to keep. DeanS, keep at it and you will more than likely confirm there is indeed a contrast difference in favor of the AP because as Daniel points out, the differences can be detected visually if one knows where to go looking for them, the published design criteria of these two scopes ensures there is a difference.  :salute:


Edited by t.r., 18 February 2017 - 06:35 AM.

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#13 starbob1

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Posted 18 February 2017 - 08:15 AM

Those AP 4in focuser look massive. That is one solid focuser it looks like. One could hang off of it. Good report.



#14 MikeBOKC

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Posted 18 February 2017 - 09:59 AM

This is sort of like "well I dated Sandra Bullock on Friday and Julia Roberts on Saturday and they were both pretty cute."

 

I doubt there are 50 people in the world who own both of these absolutely magnificent telescopes. When I saw the title of the thread I guessed that the outcome would be "too close to call." Why wouldn't it be? Hard to compare two examples of perfection!


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#15 DeanS

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Posted 18 February 2017 - 10:25 AM

What I think we all can agree on, is that it takes experience/knowledge to be able to tell the differences at this level of performance.  I certainly can't see much but again I am not a seasoned visual guy, but working on it.

 

Thanks for the comments.

 

Dean



#16 olivdeso

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Posted 18 February 2017 - 10:30 AM

One word concerning the 3,5" TCC. It was made for the 130GTX (and the GT)

 

But Rolland also tested the TCC himself, in details on the TEC140. This demontrates his level of comitment.


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#17 Derek Wong

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Posted 18 February 2017 - 01:01 PM

 

Daniel, I worded my comments carefully and they explain how I feel. My comments are my own subjective feelings. There is no right or wrong to what I've said since I am talking about myself. Others may read what I've written and have the same feelings themselves and others may not feel the same as I do.

 

Humans lack the ability to see things as they are as a general statement. When we have a conscious experience, it is the result of high level abstractions performed in the brain. These abstractions are controlled by processes in the brain that are out of our control and prevent us from seeing the true nature of the source information.

 

For example, look at the Checker Board Optical illusion: Checker Board Illusion

 

In this case, the "B" is on the same color square as the "A". If you don't believe it, make some cutouts of paper and mask everything but the "A" square and "B" square.

 

What this shows is that even when you know that you are NOT perceiving the actual shades of gray as they are, you still can't see that the two squares are the same shade of gray. Your brain has taken over and you aren't able to see the stimulus as it hit your eye.

 

I could go into a long description of my various feelings, but that would be pointless and inappropriate. The example above is one of the many reasons for my comments ... I don't think one can perform an object evaluation of two similar scopes side by side.

 

EDIT:

  • By the way, it may be easier to use a snipping tool and snip out the "A" square and "B" square and paste them into a document side by side. The result is dramatic. They are exactly the same shade of gray.
  • As you can see, even in such a dramatic example you cannot see that there is NO contrast difference between the two squares. Yet you cannot see this. So this calls into question ones ability to see subtle contrast differences in anything.
    • So to say one can objectively see subtle differences in contrast between two scopes is not consistent with the facts as to how our nervous systems work.

 

Hi Dave:

 

The checkerboard illusion shows an enhancement of our visual system to equalize colors given the perceived environment.  It is good that we do this so we recognize that there is a lion in our periphery moving through the shadows.

 

When we view Jupiter, we are looking at areas that are close together, not cutting and pasting different regions and placing them next to each other.  In the checkerboard illusion, the contrast between the two adjoining squares is preserved.

 

There are a lot of things that interfere with our abilities to differentiate between scopes, including:

 

1.  Physical including aperture differences, optical figure, color correction, and eye quality and filtration.

2.  Mechanical including collimation and cleanliness of lens.

3.  External optical factors including diagonals, eyepieces and their interaction with the optical system

4.  Environmental including seeing and thermal effects

5.  Mental - biases

 

The last category is huge, but here is an interesting summary of different biases.  I see a lot of these in myself and in this forum :D

 

http://www.nowandfut...nt-Planning.pdf

 

Regardless, I do believe that under the right conditions, there are differences between scopes, sometimes fairly dramatic.  However, the differences between high quality examples of well corrected scopes are often quite subtle, make little difference in seeing details, yet are the subject of holy wars.

 

Derek


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#18 jeremiah2229

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Posted 18 February 2017 - 01:09 PM

I've tried comparing scopes side by side. I don't think it is possible to do any sort of objective comparison

 

I am no longer of the opinion that doing sope comparisons is important. Instead, I use a scope and based on how things look over different viewing sessions, I can conclude whether or not I like the scope and enjoy the views it provides.

 

To put it differently, if someone says I've used a TEC 140 and GTX 130 side by side and the TEC is better. I'd say, who cares. I like my scopes and it doesn't matter what someone else thinks as to how one copy of a GTX compares to one copy of a TEC 140 in specific conditions as evaluated by people I don't know and so whose abilities are completely unknown to me.

 

Instead, if you were to report back as to how much you like your scope and what you looked at, that would be meaningful to me. I'd simply enjoy hearing about it and experiencing enthusiasm indirectly.

First underline:

I couldn't agree more when speaking of better glass versus better glass. Objectivity flies out the door quickly and we find ourselves sliding down the slippery subjective slope.

 

Second underline:

Wraps it up in a nut shell for me. Use each one of the specimens alone and given equal time in the eyepiece for each you will find that you start grabbing one over the other. And if you come to the point where you find it difficult to choose between them then you are blessed, be thankful and just look up.

 

 

Peace...


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#19 daveCollins

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Posted 18 February 2017 - 01:23 PM

Hi Dave:

 

 

 

The checkerboard illusion shows an enhancement of our visual system to equalize colors given the perceived environment.  It is good that we do this so we recognize that there is a lion in our periphery moving through the shadows.

 

When we view Jupiter, we are looking at areas that are close together, not cutting and pasting different regions and placing them next to each other.  In the checkerboard illusion, the contrast between the two adjoining squares is preserved.

 

There are a lot of things that interfere with our abilities to differentiate between scopes, including:

 

1.  Physical including aperture differences, optical figure, color correction, and eye quality and filtration.

2.  Mechanical including collimation and cleanliness of lens.

3.  External optical factors including diagonals, eyepieces and their interaction with the optical system

4.  Environmental including seeing and thermal effects

5.  Mental - biases

 

The last category is huge, but here is an interesting summary of different biases.  I see a lot of these in myself and in this forum :D

 

http://www.nowandfut...nt-Planning.pdf

 

Regardless, I do believe that under the right conditions, there are differences between scopes, sometimes fairly dramatic.  However, the differences between high quality examples of well corrected scopes are often quite subtle, make little difference in seeing details, yet are the subject of holy wars.

 

Derek

 

Derek, I agree with everything you say. It is an important topic and is worth at least being aware of so that we don't get blinded by our own dogma.

 

Thanks for the link to that article on Cognitive Biases. That article gives 105 reasons why being even close to objective is difficult. I only provided one, but that illusion example is convenient since it lets one see first hand how your own nervous system prevents you from seeing "reality". I do agree that seeing differences on the checkerboard is different for seeing contrast on Jupiter (of which there was almost none last night for me). The point has to do with the fact that we can't experience visual stimulation directly in the sense that our nervous system creates its own virtual reality and that is the only thing we can consciously experience. If that virtual reality was way out of sync with how the world is, we wouldn't be here today. But in terms of subtle distinctions, you cannot turn off the virtual reality.



#20 blueman

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Posted 18 February 2017 - 01:34 PM

Perhaps not Dave, but throw both scopes on an interferometer or compare their imaging abilities and I can objectively say, there will be differences that may or may not be perceived visually! ;)  I can submit a data point for the discussion or rather, three...myself and two others had both the TEC 140 and AP 130 GT at the same time for direct comparisons (I did a comprehensive 5 month comparison) and for whatever subjective reasons, we all chose the AP over the TEC to keep. DeanS, keep at it and you will more than likely confirm there is indeed a contrast difference in favor of the AP because as Daniel points out, the differences can be detected visually if one knows where to go looking for them, the published design criteria of these two scopes ensures there is a difference.  :salute:

If you have great eyes, this could very well be true. But as you age and the eyes are not as sharp, it is very hard to detect slight differences. :crazy:

Blueman


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#21 daveCollins

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Posted 18 February 2017 - 01:55 PM

Perhaps not Dave, but throw both scopes on an interferometer or compare their imaging abilities and I can objectively say, there will be differences that may or may not be perceived visually! ;)  I can submit a data point for the discussion or rather, three...myself and two others had both the TEC 140 and AP 130 GT at the same time for direct comparisons (I did a comprehensive 5 month comparison) and for whatever subjective reasons, we all chose the AP over the TEC to keep. DeanS, keep at it and you will more than likely confirm there is indeed a contrast difference in favor of the AP because as Daniel points out, the differences can be detected visually if one knows where to go looking for them, the published design criteria of these two scopes ensures there is a difference.  :salute:

t.r., there is another practical reason why I don't do side by side comparisons. I love my scopes. For example, my AP 180 f9 provides great views and has provided the best view I've ever had of the moon. The APM LZOS 175 f8 seems to be one of the finest scopes I've ever used. Why would I compare them side by side. I would run the risk of generating slightly negative views towards one of the scopes even though they are both fantastic instruments.

 

As Jeremiah2229 points out below, just use the scopes and enjoy them. Yes, in a sense I am ignoring an obvious possibility, but in return I have two scopes I love dearly instead of one.

 

The point of a side by side is generally to "determine" an winner. In simplistic terms, the other scope is a loser. So upon reading a review, some walk away feeling bad. What they just read may be just the subject views of someone they don't know and who may be biased as pointed out previously. So the obvious question is "what is the point". If instead we read reviews which described the fantastic things we saw with a scope and descriptions of how well it performed, all would be left feeling good. There would be no loser.

 

 

 

 

I've tried comparing scopes side by side. I don't think it is possible to do any sort of objective comparison

 

I am no longer of the opinion that doing sope comparisons is important. Instead, I use a scope and based on how things look over different viewing sessions, I can conclude whether or not I like the scope and enjoy the views it provides.

 

To put it differently, if someone says I've used a TEC 140 and GTX 130 side by side and the TEC is better. I'd say, who cares. I like my scopes and it doesn't matter what someone else thinks as to how one copy of a GTX compares to one copy of a TEC 140 in specific conditions as evaluated by people I don't know and so whose abilities are completely unknown to me.

 

Instead, if you were to report back as to how much you like your scope and what you looked at, that would be meaningful to me. I'd simply enjoy hearing about it and experiencing enthusiasm indirectly.

First underline:

I couldn't agree more when speaking of better glass versus better glass. Objectivity flies out the door quickly and we find ourselves sliding down the slippery subjective slope.

 

Second underline:

Wraps it up in a nut shell for me. Use each one of the specimens alone and given equal time in the eyepiece for each you will find that you start grabbing one over the other. And if you come to the point where you find it difficult to choose between them then you are blessed, be thankful and just look up.

 

 

Peace...

 


Edited by daveCollins, 18 February 2017 - 01:56 PM.

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#22 Scott99

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Posted 18 February 2017 - 10:19 PM

I find these TEC140 vs AP130 comparisons perplexing - I'm not sure I could see the difference between two models of the same scope together, but I can easily see 10mm of difference in two apo objectives.  It's not a fair fight!  For me the question would be, what does the AP do to overcome the 10mm aperture loss?  

 

It shows how people appreciate  different qualities, I see many people don't even mention the aperture difference when discussing the two scopes.  Aperture rules for me, if you're trying to see more detail in targets it's everything.  I'll take another 10mm, 5mm, 2mm...whatever I can get!


Edited by Scott99, 18 February 2017 - 10:20 PM.

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#23 DeanS

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Posted 18 February 2017 - 11:08 PM

Scott, I got nearly the same magnification in each scope, well actually 98 and 102x and there was little difference, at least to my eyes or my 2 friends.  Transparency was not great so we did mostly clusters and doubles.   Caster was a tie and which ever one is near Regulus.   On M46 I think the nebula appeared to have slightly more contrast in the AP but not sure.   I really expected to see a difference but not enough to be certain.

 

I will be happy with either scope but since I had the opportunity, and patience, to get the 130 I thought why not try them both together.  I really don't have to sell one right away so have time to work with it this summer.

 

I have the 130 mounted in my observatory now so will try some imaging next clear night.   I have no doubt it will be a great astrograph.  Just have to compare similar objects that I did with the TEC140 although with the F/L difference it will not be a direct comparison.

 

Dean

 

Something else I am interested in, since my TEC is about 5 years or so old I was wondering about improvements in coating technology.  Could better/newer coatings help make up some of the size difference?  Can the faster F/L of the AP make any difference, even though magnification was the same?  


Edited by DeanS, 18 February 2017 - 11:15 PM.


#24 olivdeso

olivdeso

    Viking 1

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Posted 19 February 2017 - 02:38 AM

The TEC140 has 2 air to glass surface. Even the "old"traveler which has also only 2 air to glass surface has a transmission factor greater than 97%.

Edit : in fact it was found to be > 98,75%:

 

http://www.baader-pl...on_01_gross.jpg

 

The TEC 140 is likely to be in the same range. Let's say about 98% +/-1%

 

The GTX has 4 air to glass surface. (2 more than the GT and the TEC). Even if the coating are 2 times better (i.e. 2 times less reflexions per air-glass surface), at the end the transmission factor is still about 98%.

 

So to me the difference between coatings (if any) will have a marginal impact on transmission, max 3%.

This can't compensate the diameter difference :

The TEC140  collects 16% more photons.


Edited by olivdeso, 19 February 2017 - 02:47 AM.


#25 stanislas-jean

stanislas-jean

    Mercury-Atlas

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Posted 19 February 2017 - 05:20 AM

What these scopes can do to-day on Mars (4.75" of disk)?

My ES127 does still, so should be better.

Interrested to have echos about.

Stanislas-Jean




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