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24mm ES 68º in an f/10 SCT Opinions...

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#1 Dave Bush

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Posted 17 August 2014 - 12:58 PM

Looking for opinions on this eyepiece's performance in an SCT at f/10.

 

I've got a Celestron Ultima 24mm and Celestron XCEL-LX 25mm both of which are wonderful but I'm wanting a bit more FOV.

 

I had the ES 82º 24mm but didn't like it.   So I'm curious about the 68º model.

 

Thanks



#2 Brian Carter

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Posted 17 August 2014 - 01:19 PM

It's my primary eyepiece in my C8. I love it. More or less sharp to the edge, little bit of field curvature and coma from the scope, but nothing to do about that. I like it because it performs well, and is also very comfortable to use. I don't wear glasses while observing though.

#3 herrointment

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Posted 17 August 2014 - 02:42 PM

No glasses here, have a heck of a time with eye placement. I like it when I can get it right. It doesn't see much use because of that issue, however.



#4 csrlice12

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Posted 17 August 2014 - 02:48 PM

Dave:  I have an ES68 24mm you can borrow for awhile to try out.  Just PM me.  I live in the Tech Center area so you're not far away....



#5 Scanning4Comets

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Posted 17 August 2014 - 07:15 PM

Excellent eyepiece @ f/10......

 

You'll love it!



#6 RGM

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Posted 18 August 2014 - 06:48 AM

I use it in my C8 with 5/4" diagonal and 6.3 FR.  I use my eyeglasses.  It works well.  Any issues you see are from the SCT design and not the eyepiece.



#7 jeffmac

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Posted 18 August 2014 - 09:49 AM

I use it in my C8 with 5/4" diagonal and 6.3 FR.  I use my eyeglasses.  It works well.  Any issues you see are from the SCT design and not the eyepiece.


Meaning, issues from the SCT design show up in the field of the 24 that the f6.3 does not clean up? Coma or field curvature?


Regards,

Jeff

#8 Brian Carter

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Posted 18 August 2014 - 09:58 AM

 

I use it in my C8 with 5/4" diagonal and 6.3 FR.  I use my eyeglasses.  It works well.  Any issues you see are from the SCT design and not the eyepiece.


Meaning, issues from the SCT design show up in the field of the 24 that the f6.3 does not clean up? Coma or field curvature?


Regards,

Jeff

 

 

 

I used it the other night with the focal reducer and it wasn't quite as good as at F/10, but I wouldn't exactly say it was objectionable either.  The last ~5% of the field started to have a smidge of astigmatism, but otherwise it was good.  The focal reducer cleaned up the field curvature nicely, I don't remember the coma, but I was specifically looking for the astigmatism because (in my experience) that is the usual faster-scope error in an eyepiece.  To give you an idea of how much astigmatism, it wasn't quite as bad as my Meade 4000 plossls at F/10, so probably I wouldn't really notice it unless I was looking for it, and it started pretty close to the field stop.  I was really pretty happy with the view with the focal reducer.

 

At F/10 it functional beautifully, there is coma and field curvature from the scope.  As far as I can see, the eyepiece doesn't introduce any real problems and is a joy to use.  It is reminiscent of how I felt about my 24panoptic when I owned it (although I haven't compared them side by side, I'm just talking of the general feeling), with the noticeable lack of pincushion distortion when panning around star fields.  In that respect, I may like it better than the panoptic.



#9 Scanning4Comets

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Posted 22 August 2014 - 05:51 PM

Actually FC comes from eyepieces, not the scope. If field curvature came from the mirror, every eyepiece would show it, and this is not the case. AFAIK, the ES 24mm 68 didn't show any astigmatism, but did show some coma, (from the mirror), and a touch of FC in my scope.


Edited by Scanning4Comets, 22 August 2014 - 05:52 PM.


#10 Brian Carter

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Posted 22 August 2014 - 05:52 PM

Dude.. Everyone knows that schmidt cassegrains have field curvature. That's why the f/6.3 reducer is also a field flattener.
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#11 jeffmac

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Posted 22 August 2014 - 06:51 PM

Thanks for the report, Brian.


Best Regards,

Jeff

#12 Scanning4Comets

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Posted 23 August 2014 - 02:01 AM

Dude.. Everyone knows that schmidt cassegrains have field curvature. That's why the f/6.3 reducer is also a field flattener.

 

I was referring to Newtonians...but you obviously missed my last sentence....Derp.


Edited by Scanning4Comets, 23 August 2014 - 02:02 AM.


#13 dpippel

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Posted 23 August 2014 - 11:28 AM

But since the OP is looking for info regarding the performance of this eyepiece in a f/10 SCT and not in a fast Newtonian... ;)


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#14 csrlice12

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Posted 23 August 2014 - 12:32 PM

Have heard from the OP, he has obtained an ES68 24mm.  We live in the same area, and hopefully this weather will clear up soon and we can meet up at the dark site.  Maybe I'll bring the 24Pan to do a comparison with the ES in his SCT and my dob.....but first, what to do about this cloud cover that seems to form every day as the sun sets......



#15 Scanning4Comets

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Posted 23 August 2014 - 02:13 PM

Have heard from the OP, he has obtained an ES68 24mm.  We live in the same area, and hopefully this weather will clear up soon and we can meet up at the dark site.  Maybe I'll bring the 24Pan to do a comparison with the ES in his SCT and my dob.....but first, what to do about this cloud cover that seems to form every day as the sun sets......

 

Now that would be so cool of you bro!

 

You rock man! :rockon:

 

Cheers !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!



#16 Scanning4Comets

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Posted 23 August 2014 - 02:23 PM

Even tho the 24m Pan is sharp to the edges in a fast scope, it does NOT play well with filters !!!

 

After viewing through my 22mm Vixen LVW at the Veil using my Lumicon O-III filter, an observing buddy walked on over to my scope, gave me his 24mm Pan without telling me what it was, and I put it in my ext tube with the Lumicon O-III in it.....well I took one look and I was like "Heyyyyyyyy, why is the view all weird?", "What is this eyepiece?", then he said "24mm Pan" and I looked and sure enough it was the 24mm Pan + Lumicon O-III.

 

The field was vignetting bigtime and it was hard to hold the view.....Well right there Mike, (junomike) walked away and just said, Ohh. LOL

 

The 22mm LVW plays much nicer with filters.....;)

 

Clear skies to ALL !!!! :love:



#17 Scanning4Comets

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Posted 23 August 2014 - 02:35 PM

But since the OP is looking for info regarding the performance of this eyepiece in a f/10 SCT and not in a fast Newtonian... ;)

 

Really? Thanks for the pro tip bro.



#18 Dennis_S253

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Posted 23 August 2014 - 03:41 PM

Gosh, I hope I didn't make a mistake. I just ordered a ES68 24mm. Both of my scopes are f\5. Also ordered a 1.25" DGM NPB Filter. 



#19 kkokkolis

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Posted 23 August 2014 - 04:14 PM

I used the ES68 24 with my f/4 Stellarview and my f/4.9 12" Newtonian and compared it with my loved Hyperion 24, a loaned Panoptic 24 and a Vixen LVW 24. Panoptic had the beat edges, Hyperion the best transmission and ES was the most balanced. I sold Hyperion and bought that same ES (and a couple of years later rebought the Hyperion). Coma has to be severe to bother me though, I mainly use the sweet spot of the field when observing. 



#20 Eddgie

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Posted 24 August 2014 - 09:04 AM

Looking for opinions on this eyepiece's performance in an SCT at f/10.

 

I've got a Celestron Ultima 24mm and Celestron XCEL-LX 25mm both of which are wonderful but I'm wanting a bit more FOV.

 

I had the ES 82º 24mm but didn't like it.   So I'm curious about the 68º model.

 

Thanks

 

I have two of these.  I was using one in my C14 before I sold the scope and liked it very much.   I also owned 27mm Pan, 22mm Pan, and 19mm Pan (along with the 20mm and 16mm ES 68s) and liked the ES every bit as much.

 

I use a pair of them in my Mark V binoviewers for my SV110ED, and even at f/7, I find them to be quite excellent performers.


Edited by Eddgie, 24 August 2014 - 09:05 AM.


#21 dpippel

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Posted 24 August 2014 - 01:12 PM

 

But since the OP is looking for info regarding the performance of this eyepiece in a f/10 SCT and not in a fast Newtonian... ;)

 

Really? Thanks for the pro tip bro.

 

 

Hey, just thought you might have missed that little point bro.



#22 Scanning4Comets

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Posted 24 August 2014 - 01:22 PM

I used the ES68 24 with my f/4 Stellarview and my f/4.9 12" Newtonian and compared it with my loved Hyperion 24, a loaned Panoptic 24 and a Vixen LVW 24. Panoptic had the beat edges, Hyperion the best transmission and ES was the most balanced. I sold Hyperion and bought that same ES (and a couple of years later rebought the Hyperion). Coma has to be severe to bother me though, I mainly use the sweet spot of the field when observing. 

 

There is no 24mm LVW....I guess you are referring to the 22mm LVW.

 

I've tested both the 24mm Pan alongside of the 22mm LVW and correction is the same for both, but the 22mm LVW plays much better with filters because the field stop in the 24mm pan is wider and vignetting occurs along with some other funky eye placement issues while using the 24mm Pan + a 1.25" filter.

 

The 22mm Vixen LVW also has better eye relief than the 24mm Pan, and the more I use the 24mm Pan, the more I dislike it personally.

 

Eye relief on the 24mm Pan isn't brutal, but I personally prefer the 22mn LVW than the 24mm Pan hands down any night.


Edited by Scanning4Comets, 24 August 2014 - 08:33 PM.


#23 george golitzin

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Posted 24 August 2014 - 01:33 PM

the 24 ES 68 was less than sharp near the edge in my f/6 dob, but still very nice to use.  I would expect it to be excellent at f/10.  Brian's report about its behavior in an SCT with focal reducer sounds close to what I saw, except the degradation started a little sooner (nearer the center) than he reports.  It's a great deal for owners of slower scopes.


Edited by george golitzin, 24 August 2014 - 01:33 PM.

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#24 kkokkolis

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Posted 24 August 2014 - 02:31 PM

There is no 24mm LVW....I guess you are referring to the 22mm LVW.

 

 Exactly. 



#25 Dennis_S253

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Posted 24 August 2014 - 08:03 PM

I'll give my report when it arrives. Can't wait...






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