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Recommend a 70 to 80mm triplet please


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As the title states, looking for recommendations for a suitable 70 to 80mm triplet around the 400 to 500mm focal length.

Uses will be as a guide scope and then also a grab and go travel scope, and third wide field imaging.

Budget is up to £1000, but could squeeze a few more pennies if necessary.

Not brand loyal, whatever fits the bill. Any real world advice from current users and images are most welcome.

Many thanks,

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The 80mm f/6 triplet from Altair, TS Optics or Tecnosky. Sharpstar 76EDPH could be another candidate. Esprit 80 also.

Edited by KP82
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WO GT81 is doublet so not really an answer to the puzzle that is ~£1000 80 triplet.

I would recommend this one (it is a bit higher than £1000 but OP said a bit more could be squeezed if need be):

https://www.altairastro.com/altair-wave-series-80mm-f6-super-ed-triplet-apo-2019-457-p.asp

alternatively, there is this one with FCD100 glass:

https://www.altairastro.com/starwave-80-ed-triplet-apo-travel-refractor-465-p.asp

that is well within a budget.

First one will be a bit better at imaging - less star bloat while second one will possibly need special lum filters to tame slight star bloat. Not 100% sure about all of that.

I have TS80 F/6 APO that is earlier version of first scope listed (at least AltairAstro says it is 2019 model - but I presume it is just batch rather than model year) and I'm really happy with it. I would not however use it as a guide scope :D. Too good to be simple guide scope. Would rather use something like ST80 for that job if guide scope is required or simply use OAG.

 

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3 hours ago, vlaiv said:

WO GT81 is doublet so not really an answer to the puzzle that is ~£1000 80 triplet.

 

The WO GT81 is a FPL53 Triplet, it's the ZS83 that's a doublet.

Both nice scopes though.

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4 minutes ago, Martthebass said:

The WO GT81 is a FPL53 Triplet, it's the ZS83 that's a doublet.

Both nice scopes though.

Is it?

My bad then. I was looking at FLO website for description and pricing:

https://www.firstlightoptics.com/william-optics/william-optics-zenithstar-81-apo.html

but I guess, I got the scope wrong, didn't I?

There is Zenithstar 81 and GT81 - two different scopes :D

 

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1 minute ago, vlaiv said:

Is it?

My bad then. I was looking at FLO website for description and pricing:

https://www.firstlightoptics.com/william-optics/william-optics-zenithstar-81-apo.html

but I guess, I got the scope wrong, didn't I?

There is Zenithstar 81 and GT81 - two different scopes :D

 

I'm wrong too Vlaiv, as it was the ZS81 doublet......what is it with WO and their stupid 1 and 2mm lens steps?  

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6 minutes ago, Martthebass said:

I'm wrong too Vlaiv, as it was the ZS81 doublet......what is it with WO and their stupid 1 and 2mm lens steps?  

It looks very much like triplets that have been mentioned above and there is high chance it comes from same factory. Maybe these lenses are a bit oversized so they can be stopped down in lens cell to avoid edge problems on image quality? Maybe WO just checks those lenses and utilizes full 81mm of aperture rather than just 80mm :D

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I would err toward an FPL-53 doublet over an FPL-51 triplet.  The correction is about the same, but the former is lighter and acclimates more quickly.

I spent $900 used a couple of years ago on a TS-Optics Photoline 90mm f/6.6 FPL-53 APO triplet.  It takes 30 minutes to acclimate, so that part is a bit annoying.  Otherwise, the images and mechanics are superb.  It's made by Sharpstar in China which has been churning out just about the best APOs lately from there.  The KUOs are about the same quality level, and both are well ahead of Synta mechanically.

My point is, educate yourself on what you want to buy as you are doing here and then watch the classifieds and jump on one when it comes up used.

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44 minutes ago, Louis D said:

I would err toward an FPL-53 doublet over an FPL-51 triplet.  The correction is about the same, but the former is lighter and acclimates more quickly.

I spent $900 used a couple of years ago on a TS-Optics Photoline 90mm f/6.6 FPL-53 APO triplet.  It takes 30 minutes to acclimate, so that part is a bit annoying.  Otherwise, the images and mechanics are superb.  It's made by Sharpstar in China which has been churning out just about the best APOs lately from there.  The KUOs are about the same quality level, and both are well ahead of Synta mechanically.

My point is, educate yourself on what you want to buy as you are doing here and then watch the classifieds and jump on one when it comes up used.

I have never noticed any temperature related issues like tube currents in the APM 80 mm triplet, unlike in my C8. I do store the telescopes in a fairly cool garage (there is a radiator there, but that is only switched on enough to prevent things freezing), so that might be the reason. I only get some reduced sharpness due to tube currents if I observe the sun with Herschel Wedge or Ca-K module without my tri-band ERF. The ERF clearly keeps the air in the tube cooler, and cuts back tube currents.

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56 minutes ago, michael.h.f.wilkinson said:

I have never noticed any temperature related issues like tube currents in the APM 80 mm triplet, unlike in my C8. I do store the telescopes in a fairly cool garage (there is a radiator there, but that is only switched on enough to prevent things freezing), so that might be the reason. I only get some reduced sharpness due to tube currents if I observe the sun with Herschel Wedge or Ca-K module without my tri-band ERF. The ERF clearly keeps the air in the tube cooler, and cuts back tube currents.

I get spiky stars with my triplet for the first 30 minutes or so at high powers, then it settles down.  Despite it claiming to have a temperature compensated lens cell, I have my doubts.

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Thanks everyone for the contributions, appreciated.

I’m closely looking at the WO GT 81, triplet 53 glass.

The other option is the esprit 80, triplet and slightly faster at F5 but a well liked and great performing scope.

Both are also checked and tuned for peace of mind.

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9 hours ago, Louis D said:

It's made by Sharpstar in China which has been churning out just about the best APOs lately from there

I would have to disagree and say no 

Edited after re-reading comment:  Maybe the best triplets from China, I don’t know, but certainly not “the best APOs” 

Edited by tooth_dr
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2 hours ago, tooth_dr said:

I would have to disagree and say no 

Edited after re-reading comment:  Maybe the best triplets from China, I don’t know, but certainly not “the best APOs” 

If you know of a better APO consistently coming out of China, I'd like to know so I can recommend them.

I will admit I forgot to mention Long-Perng's APOs which are also pretty decent.

If your budget stretches to $5000 or more, TEC and AP make excellent APOs.  I'm sure Europe has some fine locally made APOs as well, for a price.

Edited by Louis D
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6 hours ago, Louis D said:

If you know of a better APO consistently coming out of China, I'd like to know so I can recommend them.

I will admit I forgot to mention Long-Perng's APOs which are also pretty decent.

If your budget stretches to $5000 or more, TEC and AP make excellent APOs.  I'm sure Europe has some fine locally made APOs as well, for a price.

If your have a good vendor who accepts returns and the time and experience to do the QC at home.

This is my experience of a SharpStar triplet - strange spikes and CA.

image.png

Edited by tooth_dr
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9 hours ago, Neil27 said:

Thanks everyone for the contributions, appreciated.

I’m closely looking at the WO GT 81, triplet 53 glass.

The other option is the esprit 80, triplet and slightly faster at F5 but a well liked and great performing scope.

Both are also checked and tuned for peace of mind.

Great choice, but I would say that... The Flat6AIII reducer is available which takes it to just under f5 but also down to roughly 380mm too, that's how I use mine.

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18 hours ago, Louis D said:

 It's made by Sharpstar in China which has been churning out just about the best APOs lately from there.  The KUOs are about the same quality level, and both are well ahead of Synta mechanically.

Agreed. KUO used to be the top in China. Their 102, 115 and 130 f/7 triplets are well regarded. Lately Sharpstar is catching up. Their 76, 90, 107 and the new 140 all seem to be quite decent both optically and mechanically. The only problematic one is the 61. There are quite a few threads on CN talking about CA issues with the 61EDPH II and Raptor 61 (a rebadged sharpstar).

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18 minutes ago, KP82 said:

all seem to be quite decent both optically and mechanically

Not an attemp to debunk the brand, but from my own recent experience, the SS was not good optically or mechanically.

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+1 for the Esprit 80's, I have two. Why do I have 2?.. Well, I already had one from the first batch and thought I'd try out the GT81 when they came out to compare. I'd already had WO scopes before but It was awful, star shapes were naff (lens clips didn't help) and the focuser fell to bits before I'd even got a camera on it. I persevered put it back together but it wasn't for me,  I'd already been spoiled by the Esprit. It went back & was replaced with another Esprit 80. As with the first one, great out of the box!

The only thing that has slightly bothered me sometimes is the foot, as its bolted to the tube. I fix it to a larger, longer vixen or losmandy plate for easier adjustment of balance etc.

and.. don't waste it as a guide scope!.. the finder scope that comes with these makes an excellent guide scope, use that if you don't want to use an OAG. :) 

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7 hours ago, tooth_dr said:

If your have a good vendor who accepts returns and the time and experience to do the QC at home.

This is my experience of a SharpStar triplet - strange spikes and CA.

image.png

I totally get the spikes as well until it acclimates.  I was a bit shocked at first, but I gave it some time, and they settled down.  If you were still seeing them hours in, then yes, you had a bad sample.  Visually, I haven't seen any CA in focus.  It's kind of blue-green on one side of best focus and sort of red on the other.  That too, was a shock to someone who had always used reflectors where there's no color on either side of best focus.

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10 hours ago, Sp@ce_d said:

+1 for the Esprit 80's, I have two. Why do I have 2?.. Well, I already had one from the first batch and thought I'd try out the GT81 when they came out to compare. I'd already had WO scopes before but It was awful, star shapes were naff (lens clips didn't help) and the focuser fell to bits before I'd even got a camera on it. I persevered put it back together but it wasn't for me,  I'd already been spoiled by the Esprit. It went back & was replaced with another Esprit 80. As with the first one, great out of the box!

The only thing that has slightly bothered me sometimes is the foot, as its bolted to the tube. I fix it to a larger, longer vixen or losmandy plate for easier adjustment of balance etc.

and.. don't waste it as a guide scope!.. the finder scope that comes with these makes an excellent guide scope, use that if you don't want to use an OAG. :) 

Thanks everyone who has contributed and especially @Sp@ce_d for some real world conclusions regarding the WO and Esprit 👍, also @tooth_dr for your honest appraisal of the SS 94mm, which was also on my watch list.

Keeping an eye on the S/H market to see what turns up.

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12 hours ago, scotty38 said:

Great choice, but I would say that... The Flat6AIII reducer is available which takes it to just under f5 but also down to roughly 380mm too, that's how I use mine.

Thanks for the info @scotty38, I’m intrigued by the WO and it gives lovely options at both focal lengths and it sure looks pretty! Interested to know if you or anyone has imaged with the WO GT81?

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Ok the price is creeping up beyond the £1000 limit, (we can’t help ourselves can we) but overlooked this scope. Longer focal length than originally planned but the reducer and flattener are considerably cheaper than other makes.

https://www.firstlightoptics.com/stellamira-telescopes/stellamira-85mm-ed2-triplet-f6-6-apo-refractor-telescope.html

It also comes with ‘proper’ rings not some hybrid foot arrangement like the Esprit and a losmandy dovetail. Decisions, decisions 🤔.

Anyone able to give feedback on these scopes, particularly used for imaging and grab and go? I’ll Probably get one for 2022 if I order it now! 

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11 hours ago, Neil27 said:

Thanks for the info @scotty38, I’m intrigued by the WO and it gives lovely options at both focal lengths and it sure looks pretty! Interested to know if you or anyone has imaged with the WO GT81?

I have taken a few but have been plagued by (possibly self-inflicted) guiding issues over the last week or so. I think I have some reasonable data for M13 and IC1848 from the one evening it came together 🙂 Bear in mind I'm only a few months in to this hobby so my results will leave something to be desired.  I'll dig out my very first image as it's on here somewhere...

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