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Astro-Tech 102ED vs 102EDL

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#1 Sammuel

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Posted 13 September 2020 - 12:48 PM

Hi all - I'm looking to upgrade my Explore Scientific AR102 to something with similar aperture and focal length. I want to try to get the best grab-and-go scope that I can within my price range. Don't get me wrong, the AR102 is a fantastic rich-field telescope and I've totally been enjoying it. While it's truly great at low power, I feel like the brightness/clarity really falls off when I start going higher than about 50X on most DSOs. Given that the scope yields generous exit pupils with most eyepieces, I figure it must be that's what you get with standard crown and flint optics. There's also some CA in the AR102, but that's not that big of an issue for me. If I can get rid of it, then cool, but it's not my primary motivation here.

 

So I'm looking for a higher-end scope to compliment or possibly replace the AR102. Really high end is off the table, so no Takahashi or Televue for me unfortunately. Happy to entertain ideas up to around $1000 or so. I'm also leaning more toward doublets than triplets. I'm a purely visual observer so no need for AP-ready scopes here.

 

My current research has resulted in these two Astro-Tech scopes:

 

  1. AT102ED 4" f/7 - $600
  2. AT102EDL 4" f/7 - $1100

 

The stats on these two are pretty close to what I'm looking for. But the EDL version costs about twice as much as the basic ED version. What gives? What would I be paying for if I went with the EDL? Can those who know about these things comment on the difference between the optics in these two scopes? Is the upgrade to the EDL only something to consider if I want to do AP?

 

Thanks in advance. If it helps, here's a list of eyepieces that I usually use with this scope.

 

Current eyepieces:

  • ES 24mm 68*
  • Meade 18mm 60*
  • Orion Stratus 13mm 68*
  • Agena Astro 5mm "double ED"

 

Bortle 4/5 skies at about 1400' elevation.



#2 Mark9473

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Posted 13 September 2020 - 12:59 PM

Better glass in the EDL.

#3 Bomber Bob

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Posted 13 September 2020 - 01:13 PM

I'm a purely visual observer so no need for AP-ready scopes here.

 

You'll be happy with the AT102ED -- and have more $$$ for Accessories.  Get a couple of used TV eyepieces, and let this budget ED show you what it can do!


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#4 25585

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Posted 13 September 2020 - 02:34 PM

I'm a purely visual observer so no need for AP-ready scopes here.

 

You'll be happy with the AT102ED -- and have more $$$ for Accessories.  Get a couple of used TV eyepieces, and let this budget ED show you what it can do!

..or other good makes. F7 is quite tolerant.



#5 drd715

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Posted 13 September 2020 - 02:44 PM

You probably won't notice a visual difference at low and medium poweres, say up to 150X or so. If you want to push powers to a practical level of 200 or maybe 250X then in critcal fine detail and sharper edges of lunar craters you may see a slight improvement. 

 

What you are most likely to gain in the L version is a slightly better CA correction which is most noticeable when imaging. Is it worth the extra price - well for resale you should be able to retain high value in either version. 

 

So the question is are you comfortable storing an extra bit of money in the scope or are you needing to keep a tight budget for home expenses. 

 

Keep in mind this is a 4 inch class refractor and it is an excellent general use scope both as an alt/az grab and go or medium high power scope on a gem tracking mount.

 

If money is not too big of a limiting factor there is a quite interesting AT-125EDL which may prove to be a real performer to consider.

 

My choice in the 102mm size would be the EDL , but I am looking at fine resolution (sharp transition between black and white edges) as my criteria of difference. 



#6 aeajr

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Posted 13 September 2020 - 02:57 PM

Hi all - I'm looking to upgrade my Explore Scientific AR102 to something with similar aperture and focal length. I want to try to get the best grab-and-go scope that I can within my price range. Don't get me wrong, the AR102 is a fantastic rich-field telescope and I've totally been enjoying it. While it's truly great at low power, I feel like the brightness/clarity really falls off when I start going higher than about 50X on most DSOs. Given that the scope yields generous exit pupils with most eyepieces, I figure it must be that's what you get with standard crown and flint optics. There's also some CA in the AR102, but that's not that big of an issue for me. If I can get rid of it, then cool, but it's not my primary motivation here.

So I'm looking for a higher-end scope to compliment or possibly replace the AR102. Really high end is off the table, so no Takahashi or Televue for me unfortunately. Happy to entertain ideas up to around $1000 or so. I'm also leaning more toward doublets than triplets. I'm a purely visual observer so no need for AP-ready scopes here.

My current research has resulted in these two Astro-Tech scopes:

  • AT102ED 4" f/7 - $600
  • AT102EDL 4" f/7 - $1100

The stats on these two are pretty close to what I'm looking for. But the EDL version costs about twice as much as the basic ED version. What gives? What would I be paying for if I went with the EDL? Can those who know about these things comment on the difference between the optics in these two scopes? Is the upgrade to the EDL only something to consider if I want to do AP?

Thanks in advance. If it helps, here's a list of eyepieces that I usually use with this scope.

Current eyepieces:
  • ES 24mm 68*
  • Meade 18mm 60*
  • Orion Stratus 13mm 68*
  • Agena Astro 5mm "double ED"

Bortle 4/5 skies at about 1400' elevation.
You say you are concerned about brightness dropping off as you go up in power. That it going to happen with any scope of any aperture.

As you go up in mag you are viewing less and less of the captured light cone, spreading it out to create the higher mag image. Brightness is going to drop off. No way around it.

To get brighter images you need more aperture. Maybe you should be looking at the AR 127 if CA is not a concern. 55% more light capture.


When you figure prices, make sure you know what is NOT included.

I just ordered an AT102ED. I have several friends who have them and they LOVE them for visual. Makes a great companion to a large Dob or SCT.

Note that the AT102ED does not include a diagonal. So add $75 to $150 for a diagonal.

No finder scope so take that into account in your budget.

It does have rings and dovetail.

If you keep the Explore Scientific AR102 you could share the diagonal and the finder with the AT102ED. Otherwise plan to buy these

Both the ES and AT have dual speed focusers. The AR is F6.5 vs that AT at F7, so not a big change.



CA Reduction - I am no optics expert, but based on what I have read, you can expect about a 90% reduction in CA in the 102 ED as compared to the standard doublet, but not true APO triplet results. But for visual, the reports are just excellent.

The question is, what would you hope to gain for double the money, going to the EDL? Getting rid of another 6% of the CA? This is still a doublet so still not a full triplet APO.

I am upgrading from an 80 mm F5 doublet achromat. I voted with my money on the AT102ED. You may have higher expectations than I do.

Astronomics can't keep the 102 ED in stock. Not going to be available till the end of October. Don't know how many people already have claim to the next shipment or if I will get one. I can wait.

So, what is your goal for upgrading, since you say the CA doesn't really bother you? Going to ED is about CA reduction, not a brighter image, as I understand it. You may be buying for the wrong reason.

Edited by aeajr, 13 September 2020 - 03:37 PM.

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#7 Bomber Bob

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Posted 13 September 2020 - 03:21 PM

On my AT102ED, I use a GSO 2" dielectric for low & medium power; and, a Baader 1.25" prism for high power / planetary.



#8 aeajr

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Posted 13 September 2020 - 03:40 PM

On my AT102ED, I use a GSO 2" dielectric for low & medium power; and, a Baader 1.25" prism for high power / planetary.


Why?

#9 MalVeauX

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Posted 13 September 2020 - 03:56 PM

 

My current research has resulted in these two Astro-Tech scopes:

 

  1. AT102ED 4" f/7 - $600
  2. AT102EDL 4" f/7 - $1100

 

The stats on these two are pretty close to what I'm looking for. But the EDL version costs about twice as much as the basic ED version. What gives? What would I be paying for if I went with the EDL? 

The 102ED will have some CA.

The 102EDL will have no CA.

 

Very best,


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#10 Bomber Bob

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Posted 13 September 2020 - 04:07 PM

Why?

The Baader Prism is better optically than the GSO mirror -- that matters most at 50x per inch & higher.

 

Similar results when I use the AT 1.25" dielectric vs the Baader -- saw it just last night observing J&S with a 1990s Meade 390.


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#11 stevew

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Posted 13 September 2020 - 07:01 PM

  1. AT102ED 4" f/7 - $600
  2. AT102EDL 4" f/7 - $1100

 

The stats on these two are pretty close to what I'm looking for. But the EDL version costs about twice as much as the basic ED version. What gives? What would I be paying for if I went with the EDL

What you would be paying for with the AT102EDL would be better glass, with somewhat better contrast, and less chromatic aberration.  The EDL has a guaranteed .95 Strehl ratio.

I'm not sure what the Strehl ratio is of the standard AT102ED but the owners that have posted on Cloudy Nights seem pretty happy with them.

Either one would be a big improvement on deep sky, and planets over the AR102 achromat.


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#12 Jethro7

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Posted 13 September 2020 - 07:27 PM

Hello Sammuel,

I have the AT102ED, and I cannot find a fault that matters with this Refractor. I dont do AP anymore and the AT102ED was so good I sold off my Skywatcher 100mm Esprit.You dont hear that very often and in no way do I consider it a down grade. The SW100mm Esprit  was redundant and I put the money back into other Astro Gear, that I will use. I do not know how good the AT102 EDL will be. The only difference will be in the color correction with the better glass. With the AT102ED I have to be looking for the CA at high magnification to see it.Their is some but it is so small that it is neither here nor there to me.

 

HAPPY SKIES TO YOU AND KEEP LOOKING UP Jethro


Edited by Jethro7, 13 September 2020 - 07:45 PM.

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#13 Jon Isaacs

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Posted 14 September 2020 - 12:36 AM

Hi all - I'm looking to upgrade my Explore Scientific AR102 to something with similar aperture and focal length. I want to try to get the best grab-and-go scope that I can within my price range. Don't get me wrong, the AR102 is a fantastic rich-field telescope and I've totally been enjoying it. While it's truly great at low power, I feel like the brightness/clarity really falls off when I start going higher than about 50X on most DSOs. Given that the scope yields generous exit pupils with most eyepieces, I figure it must be that's what you get with standard crown and flint optics. There's also some CA in the AR102, but that's not that big of an issue for me. If I can get rid of it, then cool, but it's not my primary motivation here.

 

As has been said, when you increase the magnification, the brightness of extended objects (galaxies, nebulae, planets) drops off naturally.  Stars, being points of light, remain constant in brightness up to moderately high magnifications.

 

Whether you see it or not, the chromatic aberration represents defocused light so it does reduce the "clarity."  An apo will be sharper at higher magnifications.  

 

The difference between the AR-102, the AT-102ED and the AT-102EDL:

 

Beside the mechanical build, the differences basically in the color correction.  I owned a first generation AT-102ED, I have looked through the new generation.  These scopes are much better corrected than the AR-102 (Which I also owned) but when viewing the planets and bright double stars, there will be some false color visible.  The AR-102EDL should be almost but not quite color free at high magnifications.

 

For all around use, the AT-102ED is a very nice, affordable scope.  The AT-102EDL is the form factor and mechanical quality but should be a better performer as a planetary scope, observing at the high magnifications.  

 

If you really want a significant increase in brightness and clarity, if you want globulars to resolve, to see fainter galaxies and nebulae, more detail, then a larger scope is really the ticket.  A 4 inch, no matter how good it is, is limited by it's aperture.  When I owned the AR-102, I also had my TeleVue NP-101.  This is do it all scope that offers a very wide and very flat field along with excellent color correction and high magnification views.  

 

The AR-102 and NP-101 views were more alike than they were different.  The NP-101 provides essentially perfect views, the AR-102, somewhat flawed views but very similar nonetheless.

 

On the other hand, my $240 used on Astromart 10 inch Dob shows everything that fits in the field of view in more detail, it goes deeper, the deep sky shows in ways that even the best 4 inch cannot. 

 

Jon


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#14 Bomber Bob

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Posted 14 September 2020 - 10:23 AM

Newts are the best deal going -- $$ per aperture.  I got all 3 of mine at ~ $100 each -- Awesome Bargains!  Even with my upgrades / improvements, my vintage 1980s Meade 826 kit came in for less than I paid for my new AT102ED -- OTA only.

 

I think we've given the OP lots of good info to consider between the AT102ED & AT102EDL.  Either model is a Good ED Deal.


Edited by Bomber Bob, 14 September 2020 - 10:24 AM.

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#15 MP173

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Posted 14 September 2020 - 12:34 PM

I have owned AT102ED since June, 2019 and absolutely love it.  Of course it was a good upgrade from my ETX90RA.  

 

I have not purchased a finderscope which is a little bit of an issue for me and the Twilight 1 mount/tripod is a little wobbly on higher powers, but my satisfaction level is very high.

 

Glad to see NY Ed has one on order.  Ed is very knowledgeable of the technical side and will offer great editorial comment.

 

Ed (Indiana)


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#16 sportsmed

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Posted 14 September 2020 - 12:53 PM

Yea my vote is the 102ED, I plan on buying one myself and I'm mainly visual as well.  There isnt a point in my opinion to buy higher end refractors that most people get for AP if all your doing is visual use. Yea you get better glass so quality of image is better but the 102ED will be a performer. Plus you will have extra cash to buy other gear that you might need or want. Plus if your wanting brighter views of DSO's etc you might want to think about aperture. My 10" Dob blows small refractors away when it comes to bright detail of DSO's, but it is not a easy grab-n-go like the 102ED would be. That is one reason I love my 127mm Mak, because its a great grab-n-go and it gets used alot more then my Dob unfortunately. Just one lonely amateur astronomers opinion though haha. 


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#17 howardcano

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Posted 14 September 2020 - 12:59 PM

I've owned two 102mm f/7 scopes:  the AT102ED and the SV102 Access (which has FPL53 glass like the AT102EDL).  There is a difference in performance at high magnifications, but I found the difference to be small.  If you can afford it, go with FPL53.  If you can't, you won't be missing much.

 

If I didn't get a fantastic deal on the SV102 Access, I would have been quite happy staying with the AT102ED.  Its price/performance ratio is unbeatable.


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#18 Sammuel

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Posted 14 September 2020 - 05:11 PM

Thanks for all the great replies everyone. Really wonderful responses. For sure, I need to remember that aperture is the main component of clarity and reach as you go up in magnification.

 

I do have two larger telescopes, so I guess what I was after here was the "best" 4-inch refractor that I can find/afford. Some comments in other threads say that with higher end optics, you get better performance at higher magnification. But of course that's all tempered by what aperture you're working with.

 

In the end, I'm likely to go with the AT102ED. The price is right, I love it that the dew shield is retractable, and that you can install a standard finder scope shoe (instead of the proprietary one that comes with ES scopes). The EDL is tempting, but for purely visual I'm not sure it would be worth the extra cash.

 

Clear skies everyone!


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