Explore Scientific ED80 F6 or William Optics ZS73

[daveangie0110]

Hi All,

I am thinking of getting either the Explore Scientific ED80 F6 Essential or the William Optics ZS73, the Explore Scientific is a triplet and the William Optics is a doublet, both will cost around £800 with the flatner, can anyone give me some pros and cons regarding these two scopes, also would the image quality be better on the ED80 as it is a triplet, my imaging camera is a unmodded Canon 600D.

Thanks

[Adam J]

 

On 03/08/2018 at 07:56, daveangie0110 said:

Hi All,

I am thinking of getting either the Explore Scientific ED80 F6 Essential or the William Optics ZS73, the Explore Scientific is a triplet and the William Optics is a doublet, both will cost around £800 with the flatner, can anyone give me some pros and cons regarding these two scopes, also would the image quality be better on the ED80 as it is a triplet, my imaging camera is a unmodded Canon 600D.

Thanks

Will depend on what you want to do with it. 

From what I have read the ZS73 is despite being a doublet essentially an APO at F6. With a 80mm objective you do need a triplet objective to keep it color free at F6. 

So it comes down to focal length portability, cool down time and build quality. 

Ill stick my neck out and say that WOs build quality is better than ES. 

The 73mm doublet will be lighter, less susceptible to knocks and losing colimation and will cool down faster. So makes the better travel scope in my opinion. 

The 80mm triplet will be a little more susceptible to knocks, cool down slightly slower, be slightly more bulky, but might take a reducer to F4.8 in the future for faster imaging. 

In the end if you already have a ZS61 your not really looking for another ultra portable travel scope are you? So i would get the ES80......

Adam 

[daveangie0110]

Thanks for your reply Adam,

I am not that bothered about portability,  just looking for a better scope which will get me better images, I spoke to our guy who runs my local astronomy club he said to go for the ZS73, like you said the ES80 could become prone to losing colimation, the build quality of William Optics are excellent.

I was also looking at the Altair 80ED-R, but can not find any reviews on this scope.

 

[Adam J]

12 hours ago, daveangie0110 said:

Thanks for your reply Adam,

I am not that bothered about portability,  just looking for a better scope which will get me better images, I spoke to our guy who runs my local astronomy club he said to go for the ZS73, like you said the ES80 could become prone to losing colimation, the build quality of William Optics are excellent.

I was also looking at the Altair 80ED-R, but can not find any reviews on this scope.

 

Actually if you are not wanting portability I would personally want more focal length,  it just depends on what you want to take images of. There is not going to be a massive difference between the two. 

You are not really going to get better then the ZS73 at that price point. But you will not be able to push it faster than F6. I guess I just wory for you that its not a long way different from the ZS61 you already have.  

If you get the 80 ED-R make sure its the v2. Got to say that from the few images I have seen it take I was not blown away by the color correction. 

The only other option is to save for something like a Esprit 80ED, or GT80 at around double the cost.  

Lots of people will just tell you to get the SW80ED pro but for me the build quality is not sufficient even if the optics are excellent. I dont want to buy a scope only to replace the focuser a few months later. 

Adam

[daveangie0110]

Thanks Adam,

Which scope would you go for between the ZS73, ES80, 80ED-R or the 80EDT-R

[Adam J]

1 hour ago, daveangie0110 said:

Thanks Adam,

Which scope would you go for between the ZS73, ES80, 80ED-R or the 80EDT-R

Honestly, I would go for the ZS73 and will be doing so at some point in the future, as I do want it for my travel scope (once I finish paying for my Astrodons).

I  looked at the Starwave 80EDT-R and have considered it strongly, its not FPL-53 but FCD-100 is actually still very good glass in a triplet and the scope looks well made. Its just a little more of an unknown quantity, given were I live I would personally be tempted to head down to Altair Astros shop and take a look at one and decide based on what i see, a chat with the owners...if i was looking for a scope that was more for home use, there is a potential to take it to F4.8 with a 0.8 x reducer. This may well be better for your planned use, but not mine. 

I would not consider the other two options. 

In either case you want to budget for the 1x flattner at least. 

Adam

[newbie alert]

On 07/08/2018 at 16:59, Adam J said:

 

Will depend on what you want to do with it. 

From what I have read the ZS73 is despite being a doublet essentially an APO at F6. With a 80mm objective you do need a triplet objective to keep it color free at F6. 

 

While I agree that a triplet will be better colour corrected than a doublet I fail to see colour fringing or chromatic abberations on my ZS80D...what am I looking for?

[Adam J]

2 hours ago, newbie alert said:

While I agree that a triplet will be better colour corrected than a doublet I fail to see colour fringing or chromatic abberations on my ZS80D...what am I looking for?

It depends on the doublet its mating element, its cut and to an extent the corrector too.  I am not familiar with your scopes model I dont even know its native f-number. You would be looking for purple / blue fringes on stars.

[newbie alert]

10 hours ago, Adam J said:

It depends on the doublet its mating element, its cut and to an extent the corrector too.  I am not familiar with your scopes model I dont even know its native f-number. You would be looking for purple / blue fringes on stars.

It's native at 6.9.. f5.5 with .8 reducer..

Can't say I've noticed..even on bright stars and the moon...

[Adam J]

2 hours ago, newbie alert said:

It's native at 6.9.. f5.5 with .8 reducer..

Can't say I've noticed..even on bright stars and the moon...

Perhaps you could post an example image of something like m45 taken with an OSC? Refocusing between RGB filters not counting. 

But in any case your scope is native F6.9 not F6 as I was discussing. So if its a good quality reducer (3 / 4 element) then it should be doing a reasonable job, as far as I understand the theory. Now if you want to start at F6 and reduce that to F4.8 your going to want a triplet.  

Really am interested in seeing some example images.

Adam

[newbie alert]

M45 as a single sub? With a DSLR ok?

I'm not disputing what you say..just interested.. it maybe one of those thing where you don't see it until someone points it out!

[Adam J]

43 minutes ago, newbie alert said:

M45 as a single sub? With a DSLR ok?

I'm not disputing what you say..just interested.. it maybe one of those thing where you don't see it until someone points it out!

One other thing to note is that if you are using anything like a CLS filter that will remove a mild CA effect as it narrows the total bandwidth. 

[newbie alert]

1 hour ago, Adam J said:

One other thing to note is that if you are using anything like a CLS filter that will remove a mild CA effect as it narrows the total bandwidth. 

no cls type filter,just a single 8 min sub at iso 400 with my canon 100d

[Adam J]

32 minutes ago, newbie alert said:

no cls type filter,just a single 8 min sub at iso 400 with my canon 100d

 

Its difficult to tell from a single sub, but I would say there are some purple reflections, not sure about halos though. If this is shot at F5.5 then I would say the spacing on your reducer corrector is not right as you have some significant residual field curvature. 

[newbie alert]

2 hours ago, Adam J said:

Its difficult to tell from a single sub, but I would say there are some purple reflections, not sure about halos though. If this is shot at F5.5 then I would say the spacing on your reducer corrector is not right as you have some significant residual field curvature. 

Oops...theres a possibility it's with a skywatcher ED80...let me see if I have another one..