Which one do I get? I want to use it visually and photographically for the planets, moon and DSOs. I like the specifications of both of them, but I will choose only one.
Need help choosing between 2 refractors
Which one would you buy?
66% (21 votes)
34% (11 votes)
I suspect that like most folk I am going to answer "it depends" and then ask why just those two options and also ask about the mount that you have and its capacity. No one scope does it all and the best choice does depend upon what you want to do most. For planets and moon longer focus is usually better - a lot of photos indeed making use of barlows - so for that I'd choose the F7 probably –but also urge you perhaps also to think about Schmidt Cassegrains, Matuskovs etc as alternatives. DSOs? well again it depends - if you are a fan of wide field big vistas of HA nebulae etc then shorter focal length along with an appropriate flattener. On the other hand for seeing the detail of more compact distant DSOs such as some of the Messier galaxies (aside from the Andromeda) then again longer focus is a better fit. It also rather depends on your split between EEA, astroimaging and visual - for visual use it is a no brainer – you will see more with the bigger telescope – but for the same price a 6 or 8 inch reflector would be much better again - but that might need a mount upgrade so more cost?
Tim
Tim
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Tim Hawkes:
I suspect that like most folk I am going to answer "it depends" and then ask why just those two options and also ask about the mount that you have and its capacity. No one scope does it all and the best choice does depend upon what you want to do most. For planets and moon longer focus is usually better - a lot of photos indeed making use of barlows - so for that I'd choose the F7 probably --but also urge you perhaps also to think about Schmidt Cassegrains, Matuskovs etc as alternatives. DSOs? well again it depends - if you are a fan of wide field big vistas of HA nebulae etc then shorter focal length along with an appropriate flattener. On the other hand for seeing the detail of more compact distant DSOs such as some of the Messier galaxies (aside from the Andromeda) then again longer focus is a better fit. It also rather depends on your split between EEA, astroimaging and visual - for visual use it is a no brainer -- you will see more with the bigger telescope -- but for the same price a 6 or 8 inch reflector would be much better again - but that might need a mount upgrade so more cost?
Tim
Sorry for not mentioning my mount. Silly mistake
.1. my budget is $600-$700 (I could spend a little more if absolutely necessary)
2. my first and only mount is an AVX which supposedly works with 30lbs OTAs
3. I have thought about SCTs, but I don't like collimation (I don't really know how hard it is to collimate an SCT). I have a reflector, but it's a nightmare to collimate. About Maksutovs, I think their F/ratio is too slow for DSO photography.
I have never had a good refractor. My only 2 refractors were from Walmart and were returned a day or two after using (that was when I knew nothing about telescopes and only cared about "high magnification"
)I don't like EAA because I'm looking at a screen; I just don't like it.
I like visual and astrophotography, but will start with visual first.
AND the telescope needs to be portable and more lightweight than my 8" reflector.
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And I'm not keeping my heavy newtonian
Also I will be using a full frame DSLM not an astronomy camera (when I do AP with my new setup)
Also I will be using a full frame DSLM not an astronomy camera (when I do AP with my new setup)
I personally know nothing about the AVX mount but judging from these comments ..https://www.cloudynights.com/topic/600334-advanced-vx-vs-heq5-pro/
I get the impression that imaging might work better with the smaller scope using that mount? Also more portable. Another consideration is the quality of the focuser versus the weight of the camera plus any flattener that you might want to use (essential in my book). But - having said that - for visual the bigger one wins. So a tough call ..
I get the impression that imaging might work better with the smaller scope using that mount? Also more portable. Another consideration is the quality of the focuser versus the weight of the camera plus any flattener that you might want to use (essential in my book). But - having said that - for visual the bigger one wins. So a tough call ..
It's a tough decision. I'll wait for poll votes.
I feel that with the AVX, you should opt for the shorter fl. Definitely much more forgiving.
The only reason that I can offer an opinion is because I owned an AVX for years and know lots of folks that use it. Each copy can be quite different.
My AVX was challenging, but did get me some acceptable sessions. I struggled with the stars with my 102mm, but it handled my 61mm much better.
The full frame DSLR will also help with a wide fov and higher image scale.
Good luck and have fun!
Jim
The only reason that I can offer an opinion is because I owned an AVX for years and know lots of folks that use it. Each copy can be quite different.
My AVX was challenging, but did get me some acceptable sessions. I struggled with the stars with my 102mm, but it handled my 61mm much better.
The full frame DSLR will also help with a wide fov and higher image scale.
Good luck and have fun!
Jim
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I have an AVX, and it would work with either scope if tuned right, BUT it would pair better with the AT72EDII Lanthanum F/6 Doublet. Besides, that Lanthanum glass is supposed to produce super color. I used my AVX with a FRA400 for a couple of years and it was a good match. Good luck!
**EDIT** I just saw that you would focus on visual astro - in that case go for the AT102ED ED F/7 Doublet! Focal length matters and the AVX can handle huge loads quite well for visual use, which is why I'm not selling mine
**EDIT** I just saw that you would focus on visual astro - in that case go for the AT102ED ED F/7 Doublet! Focal length matters and the AVX can handle huge loads quite well for visual use, which is why I'm not selling mine
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Neither scope is rated for full frame camera so neither. For visual, the 102 is hands down is the better scope. For full frame astrophotography you need to up your budget and look at SharpStar or Askar, they’re the same company but some of the least expensive FF optics. Specifically the 61 and 76 EDPH are very well priced for full frame use. Others may know some other budget scopes but I wouldn’t buy a scope for full frame unless it has been verified by several owners.
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@Joe Linington Thank you for mentioning about the 61EDPH. That is a really good option.
Might I suggest neither since they are both doublet refractors? If you choose to go with them, you'll have to deal with chromatic aberration. I instead propose alternatives such as the Sharpstar 61EDPH II, Askar 65PHQ or Askar FRA300. The askar scopes would be out of your budget, but they are petzval refractors, so you wouldn't need to deal with getting a field flattener, something that is necessary if you want to do DSO imaging.
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@Pistachio_Enjoyer Agena is now selling a 61EDPHIII (version 3), so I'm trying to figure out if they will provide a flattener with the scope purchase or if I would have to get it separately (the description of the scope almost sounds as if they provide a flattener with it); If separate, I will maybe save money for an Askar petzvel instead. I have also heard that petzvels are crazy sharp.
Thx for the suggestions and CS
Thx for the suggestions and CS
I previously owned a AT72EDII clone branded as Sky Rover and I upgraded to a 102 APO Pro Triplet again branded as Sky Rover which is a clone of other brands such as TS, Altair, Tecnosky etc
The reason I upgraded to a 4" refractor is to be able to improve my image scale, gather more light and everything that comes with larger aperture and focal lenght. A bigger longer refractor gives me the possibility of imaging more objects. The F7 focal ratio is more forgiving with field correction and color correction.
Here is a a couple of targets that I imaged with the 72 then with the 102. Same camera, same filter, same location.
My images are average at best but this is not the point, I just would like to share how much is changes going from 432mm to 714 and from 72mm to 102
Keep in mind that the 102 will gather twice the amount of light the 72 does.
Trifid with the 72: https://www.astrobin.com/lw1tss/
Trifid with 102: https://www.astrobin.com/nrt61g/
Sculptor Galaxy:
https://www.astrobin.com/oichyf/
https://www.astrobin.com/rfra67/
Eagle (the 102 shot was taken using the Antlia ALP-T and was heavyly cropped):
Eagle with the 72: https://www.astrobin.com/yhe2ez/
Eagle with the 102:https://www.astrobin.com/ba162s/
The reason I upgraded to a 4" refractor is to be able to improve my image scale, gather more light and everything that comes with larger aperture and focal lenght. A bigger longer refractor gives me the possibility of imaging more objects. The F7 focal ratio is more forgiving with field correction and color correction.
Here is a a couple of targets that I imaged with the 72 then with the 102. Same camera, same filter, same location.
My images are average at best but this is not the point, I just would like to share how much is changes going from 432mm to 714 and from 72mm to 102
Keep in mind that the 102 will gather twice the amount of light the 72 does.
Trifid with the 72: https://www.astrobin.com/lw1tss/
Trifid with 102: https://www.astrobin.com/nrt61g/
Sculptor Galaxy:
https://www.astrobin.com/oichyf/
https://www.astrobin.com/rfra67/
Eagle (the 102 shot was taken using the Antlia ALP-T and was heavyly cropped):
Eagle with the 72: https://www.astrobin.com/yhe2ez/
Eagle with the 102:https://www.astrobin.com/ba162s/
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Joe Linington:
Neither scope is rated for full frame camera so neither. For visual, the 102 is hands down is the better scope. For full frame astrophotography you need to up your budget and look at SharpStar or Askar, they’re the same company but some of the least expensive FF optics. Specifically the 61 and 76 EDPH are very well priced for full frame use. Others may know some other budget scopes but I wouldn’t buy a scope for full frame unless it has been verified by several owners.
Neither Sharpstar 61 or 76 provides a flat field for APS sensor. Apparently the Askar quadruplets do. If the OP just wants to use the scope for visual then the 102 is an easy choice hands down.
And the AVX can handle the 102 with imaging gear easy. My closest "astrofriend" has an AVX that sits close to my CEM25P and my mount looks like a toy when comparing it to the AVX (maybe because it is) and my CEM25P guides my setup under 0.9rms
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Rafael Amarins:Joe Linington:
Neither scope is rated for full frame camera so neither. For visual, the 102 is hands down is the better scope. For full frame astrophotography you need to up your budget and look at SharpStar or Askar, they’re the same company but some of the least expensive FF optics. Specifically the 61 and 76 EDPH are very well priced for full frame use. Others may know some other budget scopes but I wouldn’t buy a scope for full frame unless it has been verified by several owners.
Neither Sharpstar 61 or 76 provides a flat field for APS sensor. Apparently the Askar quadruplets do. If the OP just wants to use the scope for visual then the 102 is an easy choice hands down.
And the AVX can handle the 102 with imaging gear easy. My closest "astrofriend" has an AVX that sits close to my CEM25P and my mount looks like a toy when comparing it to the AVX (maybe because it is) and my CEM25P guides my setup under 0.9rms
My 76EDPH has been my main scope with a full frame Sony A7r for almost a year and it most certainly does provide a flat frame for a full frame camera.
Hello again,
I found another cheap APO that gives beautiful images with a full frame flattener, the Evostar 72ED. The dedicated flattener is very expensive, so I was thinking, why not use a cheaper AT2FF? https://app.astrobin.com/equipment/explorer/accessory/291/astro-tech-at2ff-field-flattener
(if there are cheaper, better alternatives, I would like to know)
It should work. And it has 60mm more focal length than the 61edph and 11mm more aperture, so it can work a little better for visual planetary viewing and lunar viewing too. What do you all think?
I found another cheap APO that gives beautiful images with a full frame flattener, the Evostar 72ED. The dedicated flattener is very expensive, so I was thinking, why not use a cheaper AT2FF? https://app.astrobin.com/equipment/explorer/accessory/291/astro-tech-at2ff-field-flattener
(if there are cheaper, better alternatives, I would like to know)
It should work. And it has 60mm more focal length than the 61edph and 11mm more aperture, so it can work a little better for visual planetary viewing and lunar viewing too. What do you all think?
Engaging
Although the AT2FF description doesn't say anything about using a full frame sensor with it, people in reviews say it works with FF.
(deleted)
I think your AVX would happily manage with the AT102ED. My iOptron GEM28 handles my AT115EDT just fine. For visual and planetary, you'd want the longer focal length. However, it's at the upper end of your budget and you still haven't added a flattener (or diagonal, if you don't already have one).
They are both an ED doublet, so the chromatic aberration will be minimal, but your stars will be a bit bloated looking. William Optics has doublets with similar issues, my z61 is one of them.
If you drift more towards astrophotography, go with the shorter focal length for now. The 700mm focal length is a mid-range one, with lots of big objects being bigger than the field of view, but still not quite long enough to get close on most galaxies.
They are both an ED doublet, so the chromatic aberration will be minimal, but your stars will be a bit bloated looking. William Optics has doublets with similar issues, my z61 is one of them.
If you drift more towards astrophotography, go with the shorter focal length for now. The 700mm focal length is a mid-range one, with lots of big objects being bigger than the field of view, but still not quite long enough to get close on most galaxies.
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So back to the 61EDPH triplet I think, because I don't want bloating in my stomach. The 61EDPHIII description says this:
"In addition, 61EDPHIII is also equipped with a special full-frame flattener, providing users with more options."; it was very misleading because it sounds as if they will give a flattener with the telescope purchase (right?), but that is not true.
I asked Agena what was the meaning of that sentence and they basically said it was a mistake. Just imagine if I bought the scope expecting a flattener too; it wouldn't go too well with Agena. But they said they will correct it which is good.
"In addition, 61EDPHIII is also equipped with a special full-frame flattener, providing users with more options."; it was very misleading because it sounds as if they will give a flattener with the telescope purchase (right?), but that is not true.
I asked Agena what was the meaning of that sentence and they basically said it was a mistake. Just imagine if I bought the scope expecting a flattener too; it wouldn't go too well with Agena. But they said they will correct it which is good.
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It looks like Agena fixed the description for the Sharpstar 61 EDPHIII with the word "optional" field flattener.
Still a great price.
I have the EDPHII and I absolutely love the scope. Can't wait to swap my 102 out with it soon.
I have had it for a few years and with my small sensor ASI533 MC-P it frames M31 out perfectly! https://www.astrobin.com/z0a9v2/
Have you checked out the Astronomy Tools field of view calculator? It is extremely helpful in making decisions like this for me.
https://astronomy.tools/calculators/field_of_view/
Jim
Still a great price.
I have the EDPHII and I absolutely love the scope. Can't wait to swap my 102 out with it soon.
I have had it for a few years and with my small sensor ASI533 MC-P it frames M31 out perfectly! https://www.astrobin.com/z0a9v2/
Have you checked out the Astronomy Tools field of view calculator? It is extremely helpful in making decisions like this for me.
https://astronomy.tools/calculators/field_of_view/
Jim
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@Jim Raskett Your M31 image is very good, what was the bortle number?
I know about the FOV calculator but I don't use it often, I do need to use it more.
I know about the FOV calculator but I don't use it often, I do need to use it more.
Thanks. I’m in Bortle 6-7 skies (6 at zenith).
Jim
Jim
Rob:
I think your AVX would happily manage with the AT102ED. My iOptron GEM28 handles my AT115EDT just fine. For visual and planetary, you'd want the longer focal length. However, it's at the upper end of your budget and you still haven't added a flattener (or diagonal, if you don't already have one).
They are both an ED doublet, so the chromatic aberration will be minimal, but your stars will be a bit bloated looking. William Optics has doublets with similar issues, my z61 is one of them.
If you drift more towards astrophotography, go with the shorter focal length for now. The 700mm focal length is a mid-range one, with lots of big objects being bigger than the field of view, but still not quite long enough to get close on most galaxies.
I have the very similar SVBony SV503/102ed and it is not full frame. Great for APS-C with the reducer but not FF.
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No worries, I know what to buy now. I'll let you all know my decision once I place the order, because I've been noticing that every time I mention a telescope, it causes people to go buy it like crazy (I'm half kidding and probably half exaggerating). Just in case the company has a low stock, I will not say anything.
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