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#1 PJ007

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Posted 28 October 2019 - 08:25 PM

Hi. I am looking at the ES AR102 F6.5 Doublet Achro versus the ES ED102 F7 Triplet APO. My intended use is visibly looking at planets and some of the brighter celestial objects. No plan to do astrophotography. Seeking advice on three items pls.

 

1. Is it worth paying extra for the ED model?

 

2. Would like a stable alt/az mount, or maybe an EQ mount. Any suggestions?

 

3. Would like an illuminated finder scope that can be mounted on the ES scope. Again, any suggestions?

 

Thanks in advance.



#2 jeremiah2229

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Posted 28 October 2019 - 08:38 PM

Personally I would grab the AT102ED over the AR102. Have used both and the AT102ED is a much nicer optic for the objects you listed. Again, just my opinion and my right eye.

 

 

Peace...


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#3 Sky Muse

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Posted 28 October 2019 - 08:47 PM

Yep, this one right here...

 

https://www.astronom...ractor-ota.html

 

Mention your CN user-name during the checkout process, and you'll receive a modest discount.

 

In so far as a mount, do you prefer manual, motorised, or go-to?  


Edited by Sky Muse, 28 October 2019 - 08:50 PM.


#4 PJ007

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Posted 28 October 2019 - 08:54 PM

Sorry, I wasn’t clear on the mount. Just looking for a stable, manual alt/az. No motor, no goto.



#5 fcathell

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Posted 28 October 2019 - 08:55 PM

I was unimpressed with the AR102 in general.  Nice two speed focuser, however. For planetary it was essentially useless for any serious planetary observing due to CA. Jeremiah2229 has got the right idea.

 

Frank


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#6 drd715

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Posted 28 October 2019 - 09:32 PM

Definitely the ED for planets and lunar. These objects are bright and the achro will show much CA as purple halos. The out of focus blue/purple will fuzzy up the subtle details on the planets. Just a lack of crispness.

I use an Arcturus brand illuminated reticle two inch eyepiece sold by ccts (Jeff) that is used in a piggyback scope for alignment and aiming purposes. If you ever get a goto mount it is very helpful in doung the star alignment.

I have no direct experience with this mount, but I have seen a dual use Alt/az - GEM mount, might be Skywatcher brand that can function in Alt/az or positioned as a GEM. You could do some research on it.

Also if you are visual and planets mainly, TS makes a 107mm F-11 Ed that is very sharp that can provide you with more power per a given eyepiece. Being F-11 and an ED it has minimal if any false color. Disadvantage it is long so you need a solid mount and will be viewing seated in a chair for zenith objects.

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#7 drd715

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Posted 28 October 2019 - 10:15 PM

102mm not 107, fat fingers.

https://www.teleskop...AP-Focuser.html

545 euro

The Atlas alt/az gem is expensive though, more than this scope, but an oversized mount is a joy to use instead of a shaky jake mount.

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#8 gnowellsct

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Posted 28 October 2019 - 10:55 PM

I would actually recommend an 80 or 92 mm scope.  Then when a year or two from now when the small aperture views of Jupiter leave a little hunger for something more, the user would have a scope that is fairly easy to mount on a c8, 9.25, etc.  And then together they may ride on a better mount.

 

OTOH plenty of people here are mono-scopic, that is, dedicated to one and only one type of scope (such as refractors), and the solo-mono-scopics, which is, those who will only use one type of scope (such as a refractor) and within that category one and only one scope that's it.  And if that's the case well, there's a LOT to view in a four inch aperture.

 

But it is worth bearing in mind that just about any mount which can hold a four inch refractor well, will also be able to hold a c8 well.  Now the mount may not be able to hold BOTH well, that's a question of what kind of investment one makes up front (in the mount).

 

Greg N

 

vixen 81mm on c8.jpg


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#9 Mr. Mike

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Posted 29 October 2019 - 09:01 AM

Ive enjoyed my 102mm ES triplet quite a lot.  Perhaps I got a "good one" but it has no false color and excellent star images.  Its worth keeping them(ES) in the mix as an option for any small to moderate sized refractor.  Great service too, should you ever need it.  And they are priced sensibly.   Their ED doublets are also solid.

 

I highly recommend ED-glass if at all possible though.  False color drives me nuts and takes away from the image quality, IMO.  For deep space its not an issue but on the moon, plamets or any brighter objects you gotta have ED glass or better. 


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#10 Jeff Lee

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Posted 29 October 2019 - 10:22 AM

My ES102 puts up very good to great images. However, there shipping box and packing leaves much to be desired. I had to send two scopes back due to shipping damage. But the one I finally got is a good as I could expect. Extremely sharp images and over all because I use light in weight cameras I have no problems with the focuser that you might see some mentions of. For the price I paid, I can say you get your monies worth and I am considering a focuser upgrade only because I can. This scope is a perfect match for my C8 and I often use both for EAA on my Sirius AZ-EQ PRO. 

 

I use an inexpensive .5 reducer but hope to have a .8 reducer flattner for it soon (that way I have a 560mm f5 scope that should very good with my ZWO 294MC camera. As Surveyor 1 said this is a scope that one can use and enjoy.



#11 Binojunky

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Posted 29 October 2019 - 10:34 AM

Had two, AR102 and the 80mm ED triplet both OK , hated the L foot on the ED80 and the paint can dew shield on both, both gone, D.



#12 SeattleScott

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Posted 29 October 2019 - 10:49 AM

GSO Skyview Deluxe could work with a 4” F7 doublet. The triplet might be a bit much.

Scott
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#13 OneGear

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Posted 29 October 2019 - 07:56 PM

My Skyview Deluxe carries my AR102 achro solidly.  It would carry any of the mentioned scopes as well.

 

IMHO there's no need for a triplet for visual.  The AR102 will show some false color on the brighter objects.  For the money you can buy an 80mm ED that will show far less false color but more field curvature, require shorter focal length EP's with commensurate tighter eye relief to achieve the same magnification and gather 40% less light.  All telescopes are compromises.

 

Fwiw the AR102 with a 60mm aperture mask becomes f/11 and all but eliminates false color.  On the other hand if the ED102 triplet is an option get the triplet and don't look back.  The mount is the most important part of enjoying your telescope anyway.  Get that sorted and you start getting picky about false color.  



#14 PPPPPP42

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Posted 29 October 2019 - 08:54 PM

If you want to look at planets you will be absolutely maxing out the magnification on a 102 to see any real detail, don't go smaller.

Get the AT102ED at the least.  I would never consider an achro for planets or the moon no matter what some people say.

 

I use the stellarvue M2C manual alt/az mount system (with add on handle) with my ES 127mm FCD100 triplet and it handles it fine until I pull out the massively heavy ES eyepieces I use (see sig) and then it takes a nose dive.  With an eyepiece in it moves fluid smooth and doesn't move when you let go.  Its not possible with the roller needle bearings it uses to lock it absolutely tight so you lose your target during eyepiece changes otherwise I like it.

I use the massive wide angle lenses I do so that even with my 5.5mm I can still super easily find targets with the red dot finder I use rather than trying to do a stable swap from a lower power eyepiece.

There is sorta a crap selection of manual alt/az mounts out there.

 

I would not be happy at all with less magnification than I have with my 127mm for planetary and I absolutely love how perfectly clear and false color free the views are.  I actually plan to get an Ethos 3.7mm to really max it out which at .49mm exit pupil will be the limit I think.

 

Also keep in mind with ES you have the "essential series" which are FCD-1 glass triplets an then the more expensive FCD100 triplets which color correct better but might be slightly overkill for pure visual (I like overkill however).

 

EDIT: Here is the full system I am talking about, I have only seen it available from Stellarvue.  You really do need all the parts anyways so its easier to get as a system.  It comes with the CGEM tripod from Celestron (actually ships in their box) which is very nice.  Seems to be on backorder.

https://www.stellarv...e-mount-system/

Here is the way overpriced handle which should be included in the already expensive mount.  I bought it because I didn't like yanking on the scope itself to move it around.  Its super helpful at some angles and useless at others and a tad short but still usable with my 127mm.

https://www.stellarv...e-mounts-mh002/


Edited by PPPPPP42, 30 October 2019 - 06:16 PM.

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#15 Bomber Bob

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Posted 29 October 2019 - 09:11 PM

OTOH plenty of people here are mono-scopic, that is, dedicated to one and only one type of scope (such as refractors), and the solo-mono-scopics, which is, those who will only use one type of scope (such as a refractor) and within that category one and only one scope that's it.

 

Well, this is the Refractor Forum; and, the OP is asking about two 4" Refractors.  Do you really expect an SCT recommendation??  IF we were gonna go Off-Forum:  I got my vintage 1980s Meade 826 (8" F6 Newtonian) for a whopping $250.  It'll take the lunch money from the typical SCT, and severely challenges my APM 152ED F8 on planetary, and definitely out-resolves it on globular clusters.  But, we digress...

 

OP:  Check out this F11 ED Doublet  -->  https://www.teleskop...AP-Focuser.html

 

I've bought from TS.  They pack well, and ship fast -- and economically.  You could use this one on an alt/az or an EQ -- whichever you prefer.  You get the color correction, but with a bit of the Old Style refractor, too.  Like my 1950s Edmund 4" F15:

 

Edmund 4 - OTA Done (Mounted) S04.jpg

 

Definitely not grab & go!


Edited by Bomber Bob, 30 October 2019 - 06:04 AM.

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#16 Mr. Mike

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Posted 30 October 2019 - 02:00 PM


 

Also keep in mind with ES you have the "essential series" which are FCD-1 glass triplets an then the more expensive FCD100 triplets which color correct better but might be slightly overkill for pure visual (I like overkill however).

Absolutely - the FCD-1 glass isnt as premium as the FCD-100 but being a triplet configuration can and does help it stay color free.  I believe there is some variance from scope to scope but if you get a good FCD-1 triplet you'll be very pleased!


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#17 tomb1

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Posted 31 October 2019 - 12:15 PM

PJ,

 

I'm the proud owner of an ES AR152, the 6 inch version of the AR102. This is not a planetary scope, but when I do want to observe planets or the moon my best option is to stop down it to about 4 inch aperture (I use a paper plate with a hole cut in it and sprayed black).  Gets rid of the vast majority of the CA which is only really an issue with Jupiter and sometimes the moon.  Just thought I'd mention this solution.  I'm not recommending you run out and purchase a 6 inch refractor - it's a BIG scope.  If you're cost sensitive though, you might consider a Maksutov.  Much smaller, and better bang for the buck for the targets you've mentioned.   I've looked through the Orion 5" version at Saturn.  Great view.



#18 tomb1

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Posted 31 October 2019 - 12:17 PM

BTW,  do people actually use small (<4") APO's to do visual?  I was under the impression those were mainly intended for AP.  Pretty expensive solution for visual.  



#19 cwright

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Posted 31 October 2019 - 02:25 PM

BTW,  do people actually use small (<4") APO's to do visual?  I was under the impression those were mainly intended for AP.  Pretty expensive solution for visual.  

Ummm....yes, people use scopes of all sizes for visual. Personally, I have used a 70mm, an 80mm, and several 102mm scopes for visual observing, most of which has been deep sky. In fact, I used my ES 80mm triplet for quite a few of the Herschel 400 objects when doing that list. As crazy as it sounds, I have used my 70mm to 152mm refractors for all of my deep sky observing the last five or six years while my 18" dob stays in it's case.


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#20 Diana N

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Posted 31 October 2019 - 02:25 PM

BTW,  do people actually use small (<4") APO's to do visual?

I do!  My most-used scope is a 94mm apo refractor.  Small scopes are good performers for visual astronomy under a reasonably dark sky.


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#21 Diana N

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Posted 31 October 2019 - 03:01 PM

 Would like a stable alt/az mount, or maybe an EQ mount. Any suggestions?

In addition to the other mounts already suggested, you can consider a Discmount.  They cost the earth, but are wonderful, stable alt-az mounts.  A DM 4 would carry a 4" refractor easily; it's bigger, far heavier, and even more expensive brother the DM6 can carry up to 40 pounds without problems.



#22 SeattleScott

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Posted 31 October 2019 - 03:38 PM

BTW, do people actually use small (<4") APO's to do visual? I was under the impression those were mainly intended for AP. Pretty expensive solution for visual.

Personally I wouldn’t go lower than 90mm for visual. Might be different with dark skies.

Scott
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#23 PPPPPP42

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Posted 31 October 2019 - 08:29 PM

For DSO's you need aperture, the more the better.  If you are relying on averted vision to see your main targets of interest your aperture is too small.  Averted vision is for bonus targets and that extra bit of detail that would otherwise take a massively larger scope.

For planets you need magnification and good quality is necessary to make the best of the available magnification in a refractor.  A big image that is chromatic disaster is as useless as a tiny colored dot.

For double star splitting you need magnification and good correction is also necessary here to keep the stars as tiny correctly colored dots and not big fuzzy blobs that glow into each other and won't separate.

 

The only place for less than a 4" is wide field astrophotography where exposure time makes up for the lack of aperture, but you still want very high quality obviously.

I would never have bought even my quality 5" with the goal of it being my only visual scope.  Having used my 8" SCT I can tell you that even with a 5" aperture you are missing a ton of whats up there.  It just doesn't show up or is so faint and underwhelming or just tiny, as to be almost pointless to look at.  In my 8" many clusters look like fireworks, in my 5" they look like a brief spritz of flat white spray paint on the sky.

I love using my 5" simply because there is zero setup time or cool down time and I can just mess around with it for a half hour total and then go inside.  Eventually I will get a good mount and use it for photos as well.  For any serious visual viewing I have to drag the goto 8" out.

 

I'm just going to say "no comment" on the topic of achromats in general or masking to make up for a lack of quality.



#24 SeattleScott

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Posted 01 November 2019 - 12:49 AM

Masking is usually to compensate for CA rather than quality issues. There is some logic to it with bigger scopes, and I do it myself. Not saying my 6” masked down to 4” is as good as my 4” Apo, but the 6” is better on DSO, and the mask makes it useful on planets also. That being said, I have other larger aperture scopes I often use for DSO instead of the 6” refractor, and I don’t get the idea the OP is looking for a big refractor,

Scott

#25 Mr. Mike

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Posted 01 November 2019 - 08:14 AM

For DSO's you need aperture, the more the better.  If you are relying on averted vision to see your main targets of interest your aperture is too small.  Averted vision is for bonus targets and that extra bit of detail that would otherwise take a massively larger scope.

For planets you need magnification and good quality is necessary to make the best of the available magnification in a refractor.  A big image that is chromatic disaster is as useless as a tiny colored dot.

For double star splitting you need magnification and good correction is also necessary here to keep the stars as tiny correctly colored dots and not big fuzzy blobs that glow into each other and won't separate.

 

The only place for less than a 4" is wide field astrophotography where exposure time makes up for the lack of aperture, but you still want very high quality obviously.

I would never have bought even my quality 5" with the goal of it being my only visual scope.  Having used my 8" SCT I can tell you that even with a 5" aperture you are missing a ton of whats up there.  It just doesn't show up or is so faint and underwhelming or just tiny, as to be almost pointless to look at.  In my 8" many clusters look like fireworks, in my 5" they look like a brief spritz of flat white spray paint on the sky.

I love using my 5" simply because there is zero setup time or cool down time and I can just mess around with it for a half hour total and then go inside.  Eventually I will get a good mount and use it for photos as well.  For any serious visual viewing I have to drag the goto 8" out.

 

I'm just going to say "no comment" on the topic of achromats in general or masking to make up for a lack of quality.

No doubt that aperture is a huge asset for DSOs but it does depend on which ones, IMO.  I love star clusters(glob and open) in my 4" triplet.  I realize that Im not resolving as many stars as something with more aperture but what is seen looks fabulous.  Tack sharp, contrasty, vivid & beautiful.  The brighter nebulas are also very pleasing to me.  Dark skies go a long way for all of this too and Im blessed to have pretty decent skies right off my patio and am only about 15 mins from a killer dark-sky site.  I think galaxies is where the physical limitation of a 4" or smaller scope does really limit you.  Galaxies for me are findable but they really are just smudges and require averted vision to see them at all.  Some are simply NOT viewable.


Edited by Mr. Mike, 01 November 2019 - 08:15 AM.

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