A low power eyepiece quality upgrade?

[N3ptune]

Hi i am thinking of an upgrade, it's not certain yet, but still I want to survey.  To be used with my F5 200 x 1000 Newton (signature) I own an Orion 32mm Q70 2 inches EP and I use it quite often but am growing the need for less coma at low power, with around the same magnification, 32mm. So I am looking for a replacement  with better correction.

This is the Orion Q70 I paid 138$ for it (78 GBP) and it's 10 months old. A1 condition and was used around 20 ~ 30 times. What would be an honest price to sell it?

These are the 2 eyepieces I am interested in to replace Q70 but I don't know which one is the best bet for my F5. I am really attracted to the 68 degrees AFOV at low power (6.8mm exit pupil), but I fear it will produce more coma then the 62 version (6.4 exit pupil). 

Which one would you pick and why.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

2017-05-12 - Conclusion

I made the choice to keep my current Q70 eyepiece and enjoy it for a few more years!

[Dave In Vermont]

The first picture you posted above has a mate here:

http://www.universityoptics.com/2inch.html#WS70

Also branded at UniversityOptics in the USA. So you'd want to factor that price into your used price. I have the set of these (from UO), and if it helps - they're very nice EP's which I use quite often.

Best -

Dave

[Guest Tuomo]

What about coma correctors? I would go for the 32mm. Most of the objects fit easily 32mm fov and image is ofc crispier.

[DHEB]

+1 for the coma corrector. I use a Baader MPCC Mark III and I am very satisfied with it.

I would think twice about the 34 mm because of the 6.8 mm exit pupil. Do your eye pupils expand that much? How often are you in a dark sky that will allow that? Consider for example the ES 68 28 mm, it will give you 36x at 1.9 degrees FOV with an easily reached exit pupil of 5.6 mm. Not bad.

Just my two 0.02 €

[John]

The scope optics produce the coma and low cost wide field eyepieces show astigmatism in fastish (eg: F/5) scopes. The Q70 will show a combination of both as will the University Optics eyepiece that Dave links to which contains the same optics as the Q70's I believe.

A coma corrector will deal with most of the scope produced coma but you still need a well corrected eyepiece to be free of astigmatism in the outer parts of the field of view.

Tele Vue are the masters of controlling astigmatism but their price is high. The ES 68, 82 and 100 degree ranges are pretty well corrected. Much more so than the older, and less expensive, ES 70 degree eyepieces.

The 62 degree ES range is very new and I've yet to see performance reports on those.

My personal choice of the ones you list, for an F/5 newtonian would the ES 68 34mm.

As for selling your Q70, the general guidline is to ask 60-70% of the new retail price, assuming that the eyepiece is in nice clean condition.

 

[N3ptune]

The coma corrector, I thought about it yes. Would it be better to use the coma corrector with the Q70 then replacing Q70 it with a ES 68d ?  I am only doing visual also. (Update after john's message, it will not correct astigmatism)

http://www.telescope.com/Astrophotography/Astrophotography-Accessories/Baader-MPCC-Mark-III-Multi-Purpose-Coma-Corrector/c/4/sc/61/p/102815.uts

http://ca.skywatcher.com/product/product/f5-coma-corrector-2/#

Cinco Sauces

I already have a 25mm, I think 28mm is too close.

[N3ptune]

2 minutes ago, N3ptune said:

-

 

[John]

As I posted, a coma corrector will remove coma (as the name implies) but the eyepiece produced astigmatism will remain. Astigmatism can be more intrusive than coma.

[N3ptune]

2 minutes ago, John said:

As I posted, a coma corrector will remove coma (as the name implies) but the eyepiece produced astigmatism will remain. Astigmatism can be more intrusive than coma.

We have published our messages at the same time I believe

[John]

12 minutes ago, N3ptune said:

We have published our messages at the same time I believe

This does happen surprisingly often !

 

[N3ptune]

Ok

With maybe a slight excess of exit pupil with the ES 68d 34mm (6.8mm exit pupil + an image with a bit more brightness then my actual Q70 (6.4 mm exit pupil) Is it a logical upgrade at 400CAD? My expectations are high in term of the "wow" effect with the new ES, I want to notice difference in quality (correction) instantly.

--> Is it a good move or I am being capricious only? it has to be a killer upgrade.

 

[John]

28 minutes ago, N3ptune said:

Ok

With maybe a slight excess of exit pupil with the ES 68d 34mm (6.8mm exit pupil + an image with a bit more brightness then my actual Q70 (6.4 mm exit pupil) Is it a logical upgrade at 400CAD? My expectations are high in term of the "wow" effect with the new ES, I want to notice difference in quality (correction) instantly.

--> Is it a good move or I am being capricious only? it has to be a killer upgrade.

 

I'ms not sure that there is a "killer upgrade" really, not even a £700+ Ethos.

In the central 50% of the field of view, even in fast scopes, the majority of eyepieces perform well so you are not going to see much difference there, maybe a little but it's not likely to change your observing life. In the outer 50% of the field the stars will appear sharper and more "star like", especially in the outer 10% of the field of view, so that will be an improvement and you will be able to let objects drift futher across the field before you see distortion.

I'm trying to be balanced here - only you can decide whether the benefits are worth the additional investment. While the Orion Q70 is not perfect it's not an awful eyepiece either. 

[N3ptune]

Hemm it's a case where I have to see and compare. (maybe at an astronomy club if one day I decide to go there)

Clearly I think the perfect solution would be to have the ES 68d WITH a coma corrector, has specified by Skywatcher for my telescope.  But it's crazy expensive and right now I think the best choice is to stick with the Q70 and continue to appreciate it a few more years ((:

http://ca.skywatcher.com/product/product/bkp-200-ds-eq5-synscan-gps/

I already paid for it, it's free and it's good.

Winner a second time:

 

 

 

 

[John]

If you get a chance to try some other contenders out, take it !

 

[N3ptune]

10 minutes ago, John said:

If you get a chance to try some other contenders out, take it !

 

Yep, I should probably get up and go see some physical people, exchange gear and have fun comparing. I know I am not doing the right thing, being a loner

I have to say something about the Coma corrector solution because it was suggested.  I am not too much into that idea because it's expensive. My second point, it would only be useful with the Q70 (my other EPs are not suffering much of aberration). And now, knowing it's going to correct some coma and not astigmatism from the Q70, I have to discard that option...

Unless I could find a good used F5 coma corrector for around 150CAD taxes in. I would take a deal like that to enhance things, but it's pure luxury.

 

 

[jetstream]

Hi N3ptune, what are your targets with the widefields? Nebula?

[N3ptune]

@jetstream

That's a good question,

--> Usually when I take out the 32mm, the main purpose is to look at dense star fields, I think it's beautiful with the 70 AFOV. For giant things like the Beehive, the double double cluster, Cygnus, Lacerta and cephus, the center of Auriga also Orion's belt the incredible blue stars.I like to start with the 32mm to explore a constellation, one star at the time.

--> I bought it originally to look at large and faint nebulae with a 2" NBP filter but it's definitely not its main purpose after all.

That's the problem, I like the 70 AFOV and low power to wander around and to have a big picture.  it's bringing back sweet memories to me.

 

It'ss an all rounder.. I remember the view of the Owl and the galaxy close to it (M108), or maybe the Pinwhell and the whirlpool, all good targets to look at with this 32mm, widefield is a must (:

[alan potts]

I agree to for the 34mm ExSc as I have had the Meade version of this and it was very good. On the point of coma, I have an F4.3 dob and I don't find coma is at all bad with my Panoptics, also 68 degree. I find when I used wider FOV eyepiece it becomes more annoying and noticeable, personally I would not bother at the moment.

Alan

[N3ptune]

@alan potts

Thanks for that experience feedback with F4.3 dob and the 68mm and Panoptic. Did you noticed any astigmatism with the 68mm 34mm on your dob? and did you ever tried a Q70 with the same telescope? I don't mind getting a few subjective opinions to compare the Q70 and ES68mm.

I find it strange, and I saw that a few days ago for the Panoptic, they suggest to use a coma corrector with it on fast F4.5 Instead of saying their eyepiece has a better correction then other brands. (They probably focus on providing a solution to get no less then a perfect result with one of their product, on a fast instrument.

http://www.televue.com/engine/TV3b_page.asp?id=22&Tab=EP_EPO-35.0

If I say a 34mm 68d (6.8 exit pupil) against a Q70 70d, (6.4 exit pupil) Would the brightness difference be noticeable or barely noticeable? It's 0.3mm more exit pupil with the ES. 

I am feeding the machine with questions, I can't help it. (It's raining outside)

[John]

If you invest in a really well corrected eyepiece such as a Panoptic, Nagler, Ethos etc, for use in a really fast scope, then there is an argument that you won't get the best value from them unless you use a coma corrector with the scope as well. 

If I owned an F/4.5 scope I would certainly invest in a coma corrector otherwise my Ethos eyepieces would show up lots of (scope produced) coma in the outer parts of the field of view, thus defeating the point of using such expensive and well corrected eyepieces. As it is my fastest scope is F/5.3 in which coma is negligable. There is a touch visible in the widest field eyepieces, but only a tiny bit right out by the field stop.

[DHEB]

2 hours ago, N3ptune said:

If I say a 34mm 68d (6.8 exit pupil) against a Q70 70d, (6.4 exit pupil) Would the brightness difference be noticeable or barely noticeable? It's 0.3mm more exit pupil with the ES.

Good you pay attention to those exit pupils, lest you waste effective apperture if pupils be unnecessarily large.

Just my 0.02 €

[N3ptune]

@Cinco Sauces

Yes that's important. It would be pointless to go above 35mm EP with my scope because the image would be too bright, that's an obvious situation. But I don't feel it would be a big mess to go up to 6.8mm. It could very well be an unnoticeable loss the 0.3mm exit pupil. But if the image is too bright, this can be a direct annoyance.

Without knowing the maximum diameter of my own pupil, I say to myself,  6.5 mm exit pupil maximum. With 32mm right now, the amount of brightness is also close to maximum to my taste. That's one reason why I was also interested with the ES 32mm 62 degrees series. My Xcel-LX 25mm (120CAD EP) has almost no coma or aberration problems and it has 60 degrees only. I do this association that is easier to have a cleaner image with a smaller AFOV.  Good or medium quality optics with smaller AFOV because the telescope is a F5.

================

This is another reflection I have:

In reality if I accept to go from Q70 70 AFOV to ES 62 AFOV, and considering the optics of the ES 62 are better because it's almost twice the price:

--> I could improve the correction of coma and astigmatism (maybe a lot) for +-230CAD instead of +-380CAD for a 34mm 68d series (Compare to 138$ total for the Q70)

- The 32mm 62 degrees would be spot on for the brightness level (assuming it's the same has the Q70) and the exit pupil would also be safe (6.4mm)

Bottomline, I am exchanging 70 degrees for 62 degrees to reach more quality (correction or coma and astigmatism) at a good price (230CAD), it could be effective with a capricious F5 scope.

That or spending 800$ for a huge but well corrected 31mm Nagler Type 5 82d, but now it's another set of issues: The eyepiece is huge in size, it's really heavy and expensive, above all, it will alienate my Celestron eyepieces that the trap.

They say about Televue: Try to buy only one.

They are honest and I believe them.

[John]

If you are seeing a smaller amount off axis (which the smaller field of view eyepieces do) then you will see less coma. A 62 degree eyepiece will, generally, show less astigmatism than a 70 degree one of a similar quality as well.

As previously said, if you can try before you invest then at least you will have some assurance that your $'s will bring you improvements that matter to you.

On the exit pupil thing, I'm 57 years old and observe from a back yard with some light pollution. I've found that an exit pupil of around 4-5mm more satisfying and rewarding when hunting for fainter deep sky objects than 6mm or more. I do have a Nagler 31mm but the Ethos 21mm is usually my deep sky hunting tool of choice when using my 12" dobsonian

 

[N3ptune]

I get a good satisfaction too with my 25mm eyepiece, 5mm exit pupil, the sky is darker with it, it's a positive feature definitely. It's has good has my Q70 for faint objects too, like with your Ethos.

I will take my time with this eyepiece upgrade and try to build my motivation (from scratch) to visit an astronomy club

--> There is no regrets at all for the purchase of the Q70 10 months ago for 138CAD I used it a lot and I knew it was going to be medium grade EP from the very beginning. Some people say you have to buy the right thing the first time but I do not agree 100% with that affirmation. Sometimes it's good to build experience with less expensive material, then sell and buy something better, Q70 paid for itself many time with the experience it gave me.

(This is not a confirmation I am going to order an ES blindly right now, I don't feel it.)

Last month I went and try 5 different cars to change, this was more then 8 hours of work  --> Just to keep my current car!!! No new car was able to beat the quality/price of what I already had. 

 

[Dave In Vermont]

If you bought the scope you posted above, then it should have come with a 28mm 'LET' eyepiece with it. And my recent aquisition from Skywatcher scope - a 150mm F/12 Maksutov - did. I tried this eyepiece out while not expected any great optics. But found it very good anyways. And I was curious what sort of EP it was. I was surprised to find out it's a Kellner - with a little modification.

I was surprised! I hadn't thought about, leave alone used, one of these since I was starting out back in 1972, 3. I considered them a great step-up from what sort of EP's came with - or afford. Orthoscopics were the top-of-the-world back then. Pre-TeleVue® days. The most-common were Ramsden-design. And the differences between Ramsden & Kellner EP's was evident - even to my young (12, 13) eyes. Buying a 9mm Kellner meant a long trek to an optical-shop in Boston, Massachusetts that sold astro-goodies on public transportation. But the 9mm Kellner I ordered was worth this! They were that good.

I wish I still had that old EP. In it's little gray box, too.

But don't toss that 28mm LET eyepiece - you may have a pleasant surprise!

Enjoy!

Dave