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Need help selecting eyepieces for Evolution 6, prefer to stick to TeleVue

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#1 dalbert02

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Posted 30 May 2020 - 11:49 AM

Many many years ago (decades, sheesh!) I had a Meade ETX 90. I sold it after a few years because I thought I was going to buy a Televue 85 within weeks. Sadly, life got in the way and it didn't happen. Recently, I bought a Celestron Evolution 6 at a great price to get back in the hobby. I'd like to buy good eyepieces now with the intention of buying a Televe 101 in the not-so-distant-future. I'd really like to stick to TeleVue. May you suggest a starter TeleVue eyepiece set? Someone locally told me to get a 40mm and 20mm Plossl and then research the more expensive series. However, after just a little research, I believe I should have bought a 32mm Plossl instead of the 40mm and maybe a 19 or 24mm panoptic. May you offer some guidance, please?



#2 msl615

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Posted 30 May 2020 - 12:01 PM

Good morning from Fairbanks, Alaska (where we no longer have darkness, stars, etc for a few months) and welcome back to astro-fun!

 

Given your side-line about "decades ago" my main question for you is your eyesight, age, etc relative to any astigmatism?  I am 67 and it took me a while going through scopes and eyepiece combinations to finally realize that the marginally soft and seagull stars were not optics only, but the natural astigmatism in my own eyes.  Since then, I have moved almost exclusively to Televue eyepieces that can accept their Dioptrx  astigmatism corrector lenses and found my way back to pinpoint stars.  Even inside TV, there are eyepieces that work better and have sharper images for me given my astigmatism.

 

So, without getting into specific suggestions about which eps you might want, hopeful targets, etc, I wanted to cover this basic area first. For example, my 32TV is only used with the Dioptrx corrector regardless of the fl and aperture of the scope, because it always has a larger exit pupil. Televue has a great section on their website about these correctors.

 

I will watch your message on the forum to see what eps are suggested. 

 

Mike


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#3 Dave Mitsky

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Posted 30 May 2020 - 12:31 PM

A 24mm Panoptic has the same field stop diameter as a 32mm Plössl and will produce the same true field of view but at higher magnification and with a larger apparent field of view.  It has less eye relief, however. 

 

One of my scopes is a 6" Celestron NexStar Evolution SCT.  I prefer my 24mm Explore Scientific 68 degree eyepiece to a 30mm Celestron Ultima and the 40mm Celestron Plössl that was supplied with the telescope.  

 

I happen to own a 19mm Panoptic and use it with the SCT from time to time.  Its eye relief is even less than the 24mm version.

 

http://www.televue.c...page.asp?id=214


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#4 Tony Flanders

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Posted 30 May 2020 - 12:52 PM

A 24mm Panoptic has the same field stop diameter as a 32mm Plössl and will produce the same true field of view but at higher magnification and with a larger apparent field of view.  It has less eye relief, however.


In an f/10 scope, I personally would prefer the 32-mm Plossl to either the 24-mm Panoptic or the 40-mm Plossl. To my taste it has ideal eye relief, whereas the 24-mm Pan is too short and the 40-mm Plossl too long. Unlike the 40-mm Plossl, it has a decent 50-degree true field of view. And in an f/10 scope, it delivers a reasonably large 3.2-mm exit pupil.
 
In a fast scope, such as f/5, I would prefer the 24-mm Panoptic.

Best of all would be to get a 2-inch back for the scope, allowing the use of 2-inch eyepieces. But that would be a big, expensive step.
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#5 dalbert02

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Posted 30 May 2020 - 01:02 PM

 

 

Given your side-line about "decades ago" my main question for you is your eyesight, age, etc relative to any astigmatism? 

I had my ETX in my 20s and I'm in my late 40's now.  My eyes are pretty good, I just need low power reading glasses when on the computer for any length of time.   I assume that my vision will gradually decline with time so that is a consideration.



#6 dalbert02

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Posted 30 May 2020 - 01:05 PM

Best of all would be to get a 2-inch back for the scope, allowing the use of 2-inch eyepieces. But that would be a big, expensive step.

I hear conflicting info on this.  Some say do the 2" upgrade other say the hole in the back of the scope is 1-1/4" so a 2" back causes 'vignette' or something like that (not sure how to spell it).  



#7 jeffreym

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Posted 30 May 2020 - 02:04 PM

In my 6SE (which is the same OTA)  I used, essentially, 3 eyepieces:  24mm Panoptic, 13mm Celestron Ultima-Duo (68*), 9mm Nagler. You could sub a 13mm Delite (62*).  My sky is never very steady so going beyond 200x is about a once a year event so I typically do not pack anything shorter in focal length.  I had the ES 24mm 68* and did not like the over abundance of eye relief. It is also heavier then the 24 Pan.  I have the ES 14mm 82* and the 6.7mm 82* and like both of those very much.  I also use a 5mm Nagler from time to time.

 

TeleVue has their calculator you can use to figure out magnification and AFOV:

http://www.televue.c...=212&plain=TRUE

 

Have fun,

Jeff



#8 Jon Isaacs

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Posted 30 May 2020 - 02:08 PM

My thinking:

 

I've owned SCTs and I currently own a Televue NP-101, I've had it for 10 years.. 

 

A great variety of eyepieces work nicely in the SCT and there's no particular reason to buy Televue eyepieces. As Tony says, at F/10, the 32 mm Plossl makes sense. At F/5.4, the 24 mm Panoptic makes sense.

 

The Televue 4 inch F/5.4 refractors are very special telescopes and are very demanding on the eyepiece. What sets them apart from nearly every other 4 inch refractor is that they're very fast and they're fully corrected for field curvature.

 

In general, field curvature is only bothersome with the widest field eyepieces so it's really a scope for those looking for those essentially perfect wide, low power views. To get them, it takes eyepieces that are free of off-axis astigmatism.. this means eyepieces like the 41 mm Panoptic, the 31 mm Nagler and the 21 mm Ethos. 

 

An eyepiece like the 24 mm Panoptic will perform very well but it does do the 4 inch F/5.4 justice because it restricts it's field of view.

 

At higher powers where field curvature is not an issue, these scopes are still demanding of well corrected eyepieces because they're so fast. Eyepieces that perform well at in an F/7 refractor may not do so well off-axis in the TV-101 snd NP-101.

 

I'd buy a set of eyepieces for the C-6, there's a lot of eyepieces that will work nicely. If and when you do decide to buy a 4 inch TeleVue, that's the time to buy eyepieces well matched to it's capabilities, the scope and the eyepieces are big budget items, no TeleVue Plossls here.

 

Jon


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#9 SeattleScott

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Posted 30 May 2020 - 03:28 PM

A lot of people say the 31 Nagler is the perfect low power eyepiece for the NP101 and it probably wouldn’t vignette much with the C6. Good focal length too. It’s a big, heavy, expensive eyepiece though.

A 30mm APM UFF would go wide enough to do some justice to the NP101 without going so wide that it noticeably vignettes the C6. It is also much lighter and cheaper than the 31 Nagler. The 35 Panoptic would be the TV competitor if you want to stay TV. Basically same size FOV, also outstanding performance like the APM, but a bit heavier and more expensive than the APM. But if you have the green and want the green letters it could be the way to go. It just creates somewhat of a large exit pupil with the NP101. That’s where the 30mm APM is advantageous. Better exit pupil for the NP101.

Yeah something between 12-15mm would be excellent for the C6. The 13 Nagler comes to mind if one is restricted to TV eyepieces. Don’t know that it would be my first choice, but it would be my choice if I didn’t wear glasses and was limited to TV eyepieces. A 14 Delos would be worthy of consideration too as it has basically the same size FOV with nearly as much magnification, with enough eye relief for glasses. But you don’t wear glasses. Of course there is always the 13 Ethos but it is beyond my budget. There are 13mm hyperwides for less than the Nagler or Delos, but they aren’t TV.

For high power I have a 7 Nagler that I would recommend for a C6.

Scott

Edited by SeattleScott, 30 May 2020 - 03:31 PM.


#10 spereira

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Posted 30 May 2020 - 04:34 PM

Moving to Eyepieces, for a better fit.

 

smp



#11 Starman1

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Posted 30 May 2020 - 05:46 PM

Suggestions (since I've owned them all at one time of another):

6" f/10, 1500mm focal length.

Desirable focal lengths for 1.25":

32mm (Plössl), 50°, 47x, 1.03° true field.

 

19mm Panoptic, 68°, 79x, 0.81° true field 

or

17.3mm Delos, 72°, 87x, 0.81° true field

 

13mm Nagler Type 6, 82°, 115x, 0.67° true field

or

12mm Delos, 72°, 125x, 0.57° true field

 

9mm Nagler Type 6, 82°, 167x, 0.47° true field

or 

8mm Delos, 72°, 188x, 0.38° true field

 

I stayed with 1.25" eyepieces.

In all of them, I gave you a choice of shorter eye relief (no glasses) or longer eye relief (with glasses).

If you don't wear glasses, I'd stick with the 32mm, 19mm, 13mm, 9mm

The eyepieces are smaller and lighter and won't over-tax the star diagonal.

 

Is that all you'll ever need?  No, but it gives you a good start.


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#12 Swamp Fox

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Posted 31 May 2020 - 03:28 PM

Suggestions (since I've owned them all at one time of another):

6" f/10, 1500mm focal length.

Desirable focal lengths for 1.25":

32mm (Plössl), 50°, 47x, 1.03° true field.

 

19mm Panoptic, 68°, 79x, 0.81° true field 

or

17.3mm Delos, 72°, 87x, 0.81° true field

 

13mm Nagler Type 6, 82°, 115x, 0.67° true field

or

12mm Delos, 72°, 125x, 0.57° true field

 

9mm Nagler Type 6, 82°, 167x, 0.47° true field

or 

8mm Delos, 72°, 188x, 0.38° true field

 

I stayed with 1.25" eyepieces.

In all of them, I gave you a choice of shorter eye relief (no glasses) or longer eye relief (with glasses).

If you don't wear glasses, I'd stick with the 32mm, 19mm, 13mm, 9mm

The eyepieces are smaller and lighter and won't over-tax the star diagonal.

 

Is that all you'll ever need?  No, but it gives you a good start.

From my own experience these focal lengths work well. I recently had to move from the Ethos line to get better eye relief and have been very pleased with the 32mm, 17.3mm, 12mm and 8mm eyepieces mentioned above. 

 

Good luck with your selection, and enjoy the planning stage, I always have!

 

-Mark



#13 dalbert02

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Posted 05 June 2020 - 04:33 PM

From my own experience these focal lengths work well. I recently had to move from the Ethos line to get better eye relief and have been very pleased with the 32mm, 17.3mm, 12mm and 8mm eyepieces mentioned above. 

 

Good luck with your selection, and enjoy the planning stage, I always have!

 

-Mark

Hi Mark,

You have the same telescope I have (Celestron 6) and all the telescopes I hope to one day own the TV85, TV102 and TV127.  I'm not gonna lie, I'm kinda jealous!  May you tell me anything about your experiences with these 4 scopes?  How do they compare?  Likes?  Dislikes? Preferences? Please send by PM if it is frowned upon to change topics in a thread.  Thank you! 




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