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AT60ED vs. AT72EDII

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#1 TNmike

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Posted 17 November 2019 - 03:30 PM

I have a SW 120ED, but I do not consider it to be a G&G, or at least not a really easy one. So I am considering perhaps getting a small ED refractor such as the AT60ED or AT72EDII sometime in the future. I know the reviews for both of these are real good, and the opinions are usually that these are a good bang for the buck. Obviously they are small and have their limitations, and yet can provide unique challenges to find out what can really be found or seen using an aperture limited scope and one's own eyes. And of course they are true G&G's by anyone's definition, and thus easy to take out when limited by time or seeing (or not), but yet still want to look at a few things. So I have a couple of questions:

 

1) Obviously the 72mm has 44% more light gathering power, and two rings and a dovetail vs. one ring and foot of the 60mm, to its advantage. However, I have gotten the impression from reading extended posts that the 72mm may have a little more in terms of aberrations compared to the 60mm. Or am I misinterpreting?

 

2) If I were to get one of these, do you have a recommendation for an alt-atz mount with slo-mo controls (which I would prefer it to have)?

 

Thanks


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#2 wrvond

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Posted 17 November 2019 - 03:50 PM

A couple nights ago I had my SW120 ED and AT72 ED out doing visual with both. Surprisingly the AT was brighter than the SW. I thought perhaps it was because I had a WO 99% dielectric mirror on the AT and a Baader BBHS prism on the SW (both 2") so I swapped them. The image in the AT72 remained brighter than the SW120. Apparently there is more than just aperture affecting the view, but I can't say what that is. One thing's for sure, if the AT72 EDII is an improvement over the AT72 ED, I highly recommend it.



#3 Erik Bakker

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Posted 17 November 2019 - 03:52 PM

These small size scopes are grab-n-go at their best on good and light alt-az mounts. I settled on a Gitzo Series 3 Carbon tripod and Manfrottto HDV501 videohead. In this aperture class, 72mm can do more for low-medium deep sky observing than a 60mm scope. Although I've found that I need a tad more aperture, so over the decades I've come to the conclusion that an 80mm-ish aperture is my favorite. Under good dark skies, 72mm is wonderful, with the 80mm class going noticably deeper if optical quality is comparable. If that is no option, than 72mm would be my choice.


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#4 Moondust

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Posted 17 November 2019 - 04:38 PM

A couple nights ago I had my SW120 ED and AT72 ED out doing visual with both. Surprisingly the AT was brighter than the SW. I thought perhaps it was because I had a WO 99% dielectric mirror on the AT and a Baader BBHS prism on the SW (both 2") so I swapped them. The image in the AT72 remained brighter than the SW120. Apparently there is more than just aperture affecting the view, but I can't say what that is. One thing's for sure, if the AT72 EDII is an improvement over the AT72 ED, I highly recommend it.

I had to read this twice to make sure I had read it correctly. A 120mm has nearly 3 times the light grasp of the 72mm. There is no way a 72 is going to be brighter than a 120 unless the 120 lens is covered in mud!  Were you using the same magnification in both scopes?


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#5 Defenderslideguitar

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Posted 17 November 2019 - 05:29 PM

I think he is suggesting that something acounts for that anomally   something more than mere aperature  but does not know what it was.....

 

En re: smaller quality glass in the 60 to 72 range It seems you are on track  but I would lean towards the 72    and the AT 72 ED III is alot of bang for the buck   if it comes down to those two...

 

   but  have you also considered   what G and G  ED glass is out there in an 80mm ?

 

for me I  see going to an 80mm     I would be interested in a  travel friendly G and G     I had the Orion st 80 and while it was great for travel I sold it to comtemplate better performance     recently the WO Megres 80 FD was suggested and I am interested in that  as well as others..     Between your two choices   I'm in the AT 72 edii camp   

 

as for alt az for G and G  I had great results with the little unistar lite Larry used to make at UA......There was even a microstar   they pop up used   the Unistar lite went on any tripod astro or photo

 

 

  good luck...

Attached Thumbnails

  • unistarlite3IMG_3903.jpg
  • unistar liteIMG_3572.jpg

Edited by Defenderslideguitar, 17 November 2019 - 05:35 PM.


#6 coopman

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Posted 17 November 2019 - 05:31 PM

You & me both Moondust! 

I agree with Erik, 80mm is the best choice for a G&G refractor.


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#7 wrvond

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Posted 17 November 2019 - 07:01 PM

I had to read this twice to make sure I had read it correctly. A 120mm has nearly 3 times the light grasp of the 72mm. There is no way a 72 is going to be brighter than a 120 unless the 120 lens is covered in mud!  Were you using the same magnification in both scopes?

I had to read this twice to make sure I am not being called a liar or stupid. 

SW120= N13; AT72= N7

SW120= Pan19; AT72= N9

 

In addition to swapping the diagonals back and forth, I swapped oculars and mixed them up too. In all cases the view in the AT72 ED was brighter to my eye than the view in the SW120 ED. I'm specifically referring to looking at Alberio. Venus, Saturn and Jupiter looked pretty similar as I recall.

Keep in mind I wasn't doing any kind of scientific testing or comparison. I purchased and mounted the AT72 ED to take photos with, but since it was there, I used it along with the SW120 ED. So I wasn't consciously comparing, but it was enough of a difference to catch my attention and cause me to swap parts around to see if I could account for it. I could not come up with anything obvious.

I can't tell you how much more light gathering ability the 120 has over the 72 because I had a vasectomy and can't multiply, but I can tell when one bulb is brighter than the other...  tongue2.gif smirk.gif lol.gif

 

Perhaps you should take your SW120 ED and AT73 ED out and put them through their paces and let me know what you find out.

 

11152019001

Edited by wrvond, 17 November 2019 - 07:05 PM.

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#8 Moondust

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Posted 17 November 2019 - 10:46 PM

No one is calling you a liar or stupid, but something is definitely not adding up here.  I don't have a SW120 to compare to anything but I do have an AT72 ED 2 and owned the first generation AT72 ED previously. Comparing the brightness of view at the same power between my AT72 ED 2 and any other of the two refractors I presently own larger than 72mm, an 80mm and a 92mm, both scopes show an obviously brighter image as expected. I would expect a SW120 to show a brighter image than my 92mm apo. I previously had an AT102 ED and it certainly did. My first guess is something is going on with your SW120 where the light is not getting through to the eyepiece be it some blockage or even perhaps a focuser alignment issue. If it were normal for an AT72 ED to produce a brighter image than a SW120 than why would anyone ever buy a SW120? Why would you even be keeping yours? You should have your SW120 checked out then report back with your findings. 


Edited by Moondust, 17 November 2019 - 10:50 PM.

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#9 coopman

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Posted 18 November 2019 - 07:53 AM

Look at an open cluster such as M41 or the Double Cluster or maybe a few of the brighter DSOs & let us know what the comparison yields.    


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#10 coopman

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Posted 18 November 2019 - 07:57 AM

I enjoyed using my AT72EDII for the first 3 or 4 sessions.  The low power wide field views were great.  After the newness wore off, I found myself wishing that I was using something with more aperture and eventually sold it.  I observe in my backyard & really don't need a true grab & go scope.  


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#11 Jon Isaacs

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Posted 18 November 2019 - 08:02 AM

Perhaps you should take your SW120 ED and AT73 ED out and put them through their paces and let me know what you find out.

 

 

At one time, I did own an AT-72ED and an Orion Eon which uses the same objective as the 120mm. I know these scopes well and the difference on the planets as well as the stars was quite apparent, the larger scope performed as expected.  I suspect that if you spent some time doing a careful comparison at magnifications more appropriate for these targets, you would see the 120 mm was brighter and provided better resolution. 

 

Otherwise, the only other conclusion is that something is seriously wrong with your 120mm ED. 

 

In any event, this is really off-topic.  To answer the Mike's question:

 

Over the years, I have owned a 70mm TV Pronto, a William Optics 66SD and the AT-72ED as well as several 80mm ED scopes. My current two are an AT-80LE which is F/6, and an 80mm WO Megrez II FD which is F/7.

 

I find that an 80mm is the minimum satisfying aperture for general observing. I see enough of the planets to be happy and they provide a sufficiently wide field of view, they are still very portable and compact.

 

So, I agree with Erik, if it must be either the 60mm or the 72mm, then the 72mm but I recommend an 80mm over both those. 

 

I see the 60mm as a scope I might want in addition to my 80mm apos because it can provide an even wider field of view. But for that, the ST-80 with a 2 inch focuser goes nearly as wide and has more aperture to back that up.

 

Jon


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#12 TNmike

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Posted 22 November 2019 - 11:45 AM

For those that have the AT60ED, how well does the single ring/foot, in and of itself, hold the scope? Or does it need rings?



#13 desertlens

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Posted 22 November 2019 - 01:18 PM

The AT60ED is so short and focuser heavy that rings are untenable. The stock foot, used under the scope, will work quite well with any video fluid head. I added a short dovetail bar and rotated the ring/foot to the port side of the scope for use with a Stellarvue M1v mount head. This works very well for me and provides some flexibility for balancing. I've posted this photo elsewhere but you may not have seen it.

 

AT60ED.jpg

 

Here's a different scope with a more flexible ring design:

https://agenaastro.c...ope-61edph.html


Edited by desertlens, 22 November 2019 - 01:20 PM.

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#14 ValhallaObserver

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Posted 28 November 2019 - 11:30 PM

I have a Stellarvue SV50 ED APO and a AT-72EDII. Both are nice. I would like a SV70T all things considered but it comes at a much more considerable cost. I think the SV product is better made. I think buying the AT-72EDII would be a goo choice as you get more aperture for not lot more weight, size, and cost.

 

I really like the SV50 good things can come in small packages. This is not a finderscope or a lil rasca,l but a true 50mm ED. Get a sweet TV eyepiece from Done say a 5-7 MM TV or Vixen you will be in lightweight heaven on a solid tripod.

 

VO




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